diff --git a/readium/lcp/src/main/java/org/readium/r2/lcp/LcpContentProtection.kt b/readium/lcp/src/main/java/org/readium/r2/lcp/LcpContentProtection.kt
index 4038bb1d67..ed6646c877 100644
--- a/readium/lcp/src/main/java/org/readium/r2/lcp/LcpContentProtection.kt
+++ b/readium/lcp/src/main/java/org/readium/r2/lcp/LcpContentProtection.kt
@@ -28,9 +28,7 @@ import org.readium.r2.shared.util.data.decodeRwpm
 import org.readium.r2.shared.util.data.decodeXml
 import org.readium.r2.shared.util.data.readDecodeOrElse
 import org.readium.r2.shared.util.flatMap
-import org.readium.r2.shared.util.format.EpubSpecification
-import org.readium.r2.shared.util.format.LcpLicenseSpecification
-import org.readium.r2.shared.util.format.LcpSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.getOrElse
 import org.readium.r2.shared.util.resource.Resource
 import org.readium.r2.shared.util.resource.TransformingContainer
@@ -57,7 +55,7 @@ internal class LcpContentProtection(
         allowUserInteraction: Boolean
     ): Try<ContentProtection.OpenResult, ContentProtection.OpenError> {
         if (
-            !asset.format.conformsTo(LcpSpecification)
+            !asset.format.conformsTo(Specification.Lcp)
         ) {
             return Try.failure(ContentProtection.OpenError.AssetNotSupported())
         }
@@ -91,7 +89,7 @@ internal class LcpContentProtection(
 
         val encryptionData =
             when {
-                asset.format.conformsTo(EpubSpecification) -> parseEncryptionDataEpub(
+                asset.format.conformsTo(Specification.Epub) -> parseEncryptionDataEpub(
                     asset.container
                 )
                 else -> parseEncryptionDataRpf(asset.container)
@@ -151,7 +149,7 @@ internal class LcpContentProtection(
         credentials: String?,
         allowUserInteraction: Boolean
     ): Try<ContentProtection.OpenResult, ContentProtection.OpenError> {
-        if (!licenseAsset.format.conformsTo(LcpLicenseSpecification)) {
+        if (!licenseAsset.format.conformsTo(Specification.LcpLicense)) {
             return Try.failure(ContentProtection.OpenError.AssetNotSupported())
         }
 
diff --git a/readium/lcp/src/main/java/org/readium/r2/lcp/license/container/LicenseContainer.kt b/readium/lcp/src/main/java/org/readium/r2/lcp/license/container/LicenseContainer.kt
index b966d1b387..20f4b72b20 100644
--- a/readium/lcp/src/main/java/org/readium/r2/lcp/license/container/LicenseContainer.kt
+++ b/readium/lcp/src/main/java/org/readium/r2/lcp/license/container/LicenseContainer.kt
@@ -19,9 +19,8 @@ import org.readium.r2.shared.util.asset.Asset
 import org.readium.r2.shared.util.asset.ContainerAsset
 import org.readium.r2.shared.util.asset.ResourceAsset
 import org.readium.r2.shared.util.data.Container
-import org.readium.r2.shared.util.format.EpubSpecification
 import org.readium.r2.shared.util.format.FormatSpecification
-import org.readium.r2.shared.util.format.LcpLicenseSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.resource.Resource
 
 private val LICENSE_IN_EPUB = Url("META-INF/license.lcpl")!!
@@ -44,11 +43,11 @@ internal fun createLicenseContainer(
     formatSpecification: FormatSpecification
 ): WritableLicenseContainer =
     when {
-        formatSpecification.conformsTo(EpubSpecification) -> FileZipLicenseContainer(
+        formatSpecification.conformsTo(Specification.Epub) -> FileZipLicenseContainer(
             file.path,
             LICENSE_IN_EPUB
         )
-        formatSpecification.conformsTo(LcpLicenseSpecification) -> LcplLicenseContainer(file)
+        formatSpecification.conformsTo(Specification.LcpLicense) -> LcplLicenseContainer(file)
         // Assuming it's a Readium WebPub package (e.g. audiobook, LCPDF, etc.) as a fallback
         else -> FileZipLicenseContainer(file.path, LICENSE_IN_RPF)
     }
@@ -70,7 +69,7 @@ internal fun createLicenseContainer(
     resource: Resource,
     formatSpecification: FormatSpecification
 ): LicenseContainer {
-    if (!formatSpecification.conformsTo(LcpLicenseSpecification)) {
+    if (!formatSpecification.conformsTo(Specification.LcpLicense)) {
         throw LcpException(LcpError.Container.OpenFailed)
     }
 
@@ -88,7 +87,7 @@ internal fun createLicenseContainer(
     formatSpecification: FormatSpecification
 ): LicenseContainer {
     val licensePath = when {
-        formatSpecification.conformsTo(EpubSpecification) -> LICENSE_IN_EPUB
+        formatSpecification.conformsTo(Specification.Epub) -> LICENSE_IN_EPUB
         // Assuming it's a Readium WebPub package (e.g. audiobook, LCPDF, etc.) as a fallback
         else -> LICENSE_IN_RPF
     }
diff --git a/readium/lcp/src/main/java/org/readium/r2/lcp/service/LicensesService.kt b/readium/lcp/src/main/java/org/readium/r2/lcp/service/LicensesService.kt
index 8773a8cf82..7fbef1e163 100644
--- a/readium/lcp/src/main/java/org/readium/r2/lcp/service/LicensesService.kt
+++ b/readium/lcp/src/main/java/org/readium/r2/lcp/service/LicensesService.kt
@@ -42,12 +42,10 @@ import org.readium.r2.shared.util.FileExtension
 import org.readium.r2.shared.util.Try
 import org.readium.r2.shared.util.asset.Asset
 import org.readium.r2.shared.util.asset.AssetRetriever
-import org.readium.r2.shared.util.format.EpubSpecification
 import org.readium.r2.shared.util.format.Format
 import org.readium.r2.shared.util.format.FormatHints
 import org.readium.r2.shared.util.format.FormatSpecification
-import org.readium.r2.shared.util.format.LcpSpecification
-import org.readium.r2.shared.util.format.ZipSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.getOrElse
 import org.readium.r2.shared.util.mediatype.MediaType
 import timber.log.Timber
@@ -71,14 +69,23 @@ internal class LicensesService(
         licenseDocument: LicenseDocument,
         publicationFile: File
     ): Try<Unit, LcpError> {
+        val hashIsCorrect = licenseDocument.publicationLink.hash
+            ?.let { publicationFile.checkSha256(it) }
+
+        if (hashIsCorrect == false) {
+            return Try.failure(
+                LcpError.Network(Exception("Digest mismatch: download looks corrupted."))
+            )
+        }
+
         val mediaType = licenseDocument.publicationLink.mediaType
         val format = assetRetriever.sniffFormat(publicationFile, FormatHints(mediaType))
             .getOrElse {
                 Format(
                     specification = FormatSpecification(
-                        ZipSpecification,
-                        EpubSpecification,
-                        LcpSpecification
+                        Specification.Zip,
+                        Specification.Epub,
+                        Specification.Lcp
                     ),
                     mediaType = MediaType.EPUB,
                     fileExtension = FileExtension("epub")
@@ -152,13 +159,14 @@ internal class LicensesService(
             onProgress = onProgress
         )
 
-        license.publicationLink.hash
-            ?.takeIf { destination.checkSha256(it) == false }
-            ?.run {
-                throw LcpException(
-                    LcpError.Network(Exception("Digest mismatch: download looks corrupted."))
-                )
-            }
+        val hashIsCorrect = license.publicationLink.hash
+            ?.let { destination.checkSha256(it) }
+
+        if (hashIsCorrect == false) {
+            throw LcpException(
+                LcpError.Network(Exception("Digest mismatch: download looks corrupted."))
+            )
+        }
 
         val format =
             assetRetriever.sniffFormat(
@@ -179,9 +187,9 @@ internal class LicensesService(
                     is AssetRetriever.RetrieveError.FormatNotSupported -> {
                         Format(
                             specification = FormatSpecification(
-                                ZipSpecification,
-                                EpubSpecification,
-                                LcpSpecification
+                                Specification.Zip,
+                                Specification.Epub,
+                                Specification.Lcp
                             ),
                             mediaType = MediaType.EPUB,
                             fileExtension = FileExtension("epub")
diff --git a/readium/shared/src/main/java/org/readium/r2/shared/publication/protection/FallbackContentProtection.kt b/readium/shared/src/main/java/org/readium/r2/shared/publication/protection/FallbackContentProtection.kt
index 9e780c5fd4..926fd3391e 100644
--- a/readium/shared/src/main/java/org/readium/r2/shared/publication/protection/FallbackContentProtection.kt
+++ b/readium/shared/src/main/java/org/readium/r2/shared/publication/protection/FallbackContentProtection.kt
@@ -14,8 +14,7 @@ import org.readium.r2.shared.util.Error
 import org.readium.r2.shared.util.Try
 import org.readium.r2.shared.util.asset.Asset
 import org.readium.r2.shared.util.asset.ContainerAsset
-import org.readium.r2.shared.util.format.AdeptSpecification
-import org.readium.r2.shared.util.format.LcpSpecification
+import org.readium.r2.shared.util.format.Specification
 
 /**
  * [ContentProtection] implementation used as a fallback when detecting known DRMs
@@ -35,9 +34,9 @@ public class FallbackContentProtection : ContentProtection {
         }
 
         val protectionServiceFactory = when {
-            asset.format.conformsTo(LcpSpecification) ->
+            asset.format.conformsTo(Specification.Lcp) ->
                 Service.createFactory(Scheme.Lcp, "Readium LCP")
-            asset.format.conformsTo(AdeptSpecification) ->
+            asset.format.conformsTo(Specification.Adept) ->
                 Service.createFactory(Scheme.Adept, "Adobe ADEPT")
             else ->
                 return Try.failure(ContentProtection.OpenError.AssetNotSupported())
diff --git a/readium/shared/src/main/java/org/readium/r2/shared/publication/services/CoverService.kt b/readium/shared/src/main/java/org/readium/r2/shared/publication/services/CoverService.kt
index 0239c692e3..afa0d5e681 100644
--- a/readium/shared/src/main/java/org/readium/r2/shared/publication/services/CoverService.kt
+++ b/readium/shared/src/main/java/org/readium/r2/shared/publication/services/CoverService.kt
@@ -11,6 +11,8 @@ package org.readium.r2.shared.publication.services
 
 import android.graphics.Bitmap
 import android.util.Size
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
 import org.readium.r2.shared.extensions.scaleToFit
 import org.readium.r2.shared.publication.Link
 import org.readium.r2.shared.publication.Publication
@@ -76,15 +78,16 @@ internal class ResourceCoverService(
     private val container: Container<Resource>
 ) : CoverService {
 
-    override suspend fun cover(): Bitmap? {
-        val resource = container[coverUrl]
-            ?: return null
+    override suspend fun cover(): Bitmap? =
+        withContext(Dispatchers.IO) {
+            val resource = container[coverUrl]
+                ?: return@withContext null
 
-        return resource
-            .read()
-            .flatMap { it.decodeBitmap() }
-            .getOrNull()
-    }
+            return@withContext resource
+                .read()
+                .flatMap { it.decodeBitmap() }
+                .getOrNull()
+        }
 
     companion object {
 
diff --git a/readium/shared/src/main/java/org/readium/r2/shared/util/format/Format.kt b/readium/shared/src/main/java/org/readium/r2/shared/util/format/Format.kt
index 7343b63bb0..f1696647ec 100644
--- a/readium/shared/src/main/java/org/readium/r2/shared/util/format/Format.kt
+++ b/readium/shared/src/main/java/org/readium/r2/shared/util/format/Format.kt
@@ -61,91 +61,93 @@ public value class FormatSpecification(public val specifications: Set<Specificat
         specifications.containsAll(other.specifications)
 }
 
-public interface Specification
-
-/*
- * Archive specifications
- */
-public object ZipSpecification : Specification
-public object RarSpecification : Specification
-
-/*
- * Syntax specifications
- */
-public object JsonSpecification : Specification
-public object XmlSpecification : Specification
-
-/*
- * Publication manifest specifications
- */
-public object W3cPubManifestSpecification : Specification
-public object RwpmSpecification : Specification
-
-/*
- * Technical document specifications
- */
-public object ProblemDetailsSpecification : Specification
-public object LcpLicenseSpecification : Specification
-
-/*
- * Media format specifications
- */
-public object PdfSpecification : Specification
-public object HtmlSpecification : Specification
-
-/*
- * Drm specifications
- */
-public object LcpSpecification : Specification
-public object AdeptSpecification : Specification
-
-/*
- * Bitmap specifications
- */
-public object AvifSpecification : Specification
-public object BmpSpecification : Specification
-public object GifSpecification : Specification
-public object JpegSpecification : Specification
-public object JxlSpecification : Specification
-public object PngSpecification : Specification
-public object TiffSpecification : Specification
-public object WebpSpecification : Specification
-
-/*
- * Audio specifications
- */
-public object AacSpecification : Specification
-public object AiffSpecification : Specification
-public object FlacSpecification : Specification
-public object Mp4Specification : Specification
-public object Mp3Specification : Specification
-public object OggSpecification : Specification
-public object OpusSpecification : Specification
-public object WavSpecification : Specification
-public object WebmSpecification : Specification
-
-/*
- * Publication package specifications
- */
-public object EpubSpecification : Specification
-public object RpfSpecification : Specification
-public object LpfSpecification : Specification
-public object InformalAudiobookSpecification : Specification
-public object InformalComicSpecification : Specification
-
-/*
- * Opds specifications
- */
-public object Opds1CatalogSpecification : Specification
-public object Opds1EntrySpecification : Specification
-public object Opds2CatalogSpecification : Specification
-public object Opds2PublicationSpecification : Specification
-public object OpdsAuthenticationSpecification : Specification
-
-/*
- * Language specifications
- */
-
-public object JavaScriptSpecification : Specification
-
-public object CssSpecification : Specification
+public interface Specification {
+
+    public companion object {}
+
+    /*
+     * Archive specifications
+     */
+    public object Zip : Specification
+    public object Rar : Specification
+
+    /*
+     * Syntax specifications
+     */
+    public object Json : Specification
+    public object Xml : Specification
+
+    /*
+     * Publication manifest specifications
+     */
+    public object W3cPubManifest : Specification
+    public object Rwpm : Specification
+
+    /*
+     * Technical document specifications
+     */
+    public object ProblemDetails : Specification
+    public object LcpLicense : Specification
+
+    /*
+     * Media format specifications
+     */
+    public object Pdf : Specification
+    public object Html : Specification
+
+    /*
+     * Drm specifications
+     */
+    public object Lcp : Specification
+    public object Adept : Specification
+
+    /*
+     * Bitmap specifications
+     */
+    public object Avif : Specification
+    public object Bmp : Specification
+    public object Gif : Specification
+    public object Jpeg : Specification
+    public object Jxl : Specification
+    public object Png : Specification
+    public object Tiff : Specification
+    public object Webp : Specification
+
+    /*
+     * Audio specifications
+     */
+    public object Aac : Specification
+    public object Aiff : Specification
+    public object Flac : Specification
+    public object Mp4 : Specification
+    public object Mp3 : Specification
+    public object Ogg : Specification
+    public object Opus : Specification
+    public object Wav : Specification
+    public object Webm : Specification
+
+    /*
+     * Publication package specifications
+     */
+    public object Epub : Specification
+    public object Rpf : Specification
+    public object Lpf : Specification
+    public object InformalAudiobook : Specification
+    public object InformalComic : Specification
+
+    /*
+     * Opds specifications
+     */
+    public object Opds1Catalog : Specification
+    public object Opds1Entry : Specification
+    public object Opds2Catalog : Specification
+    public object Opds2Publication : Specification
+    public object OpdsAuthentication : Specification
+
+    /*
+     * Language specifications
+     */
+
+    public object JavaScript : Specification
+    public object Css : Specification
+}
diff --git a/readium/shared/src/main/java/org/readium/r2/shared/util/format/Sniffers.kt b/readium/shared/src/main/java/org/readium/r2/shared/util/format/Sniffers.kt
index 4ec63346f3..d063eaeffa 100644
--- a/readium/shared/src/main/java/org/readium/r2/shared/util/format/Sniffers.kt
+++ b/readium/shared/src/main/java/org/readium/r2/shared/util/format/Sniffers.kt
@@ -54,7 +54,7 @@ public object HtmlSniffer : FormatSniffer {
         format: Format,
         source: Readable
     ): Try<Format, ReadError> {
-        if (format.hasMoreThan(XmlSpecification) || !source.canReadWholeBlob()) {
+        if (format.hasMoreThan(Specification.Xml) || !source.canReadWholeBlob()) {
             return Try.success(format)
         }
 
@@ -87,13 +87,13 @@ public object HtmlSniffer : FormatSniffer {
     }
 
     private val htmlFormat = Format(
-        specification = FormatSpecification(HtmlSpecification),
+        specification = FormatSpecification(Specification.Html),
         fileExtension = FileExtension("html"),
         mediaType = MediaType.HTML
     )
 
     private val xhtmlFormat = Format(
-        specification = FormatSpecification(XmlSpecification, HtmlSpecification),
+        specification = FormatSpecification(Specification.Xml, Specification.Html),
         fileExtension = FileExtension("xhtml"),
         mediaType = MediaType.XHTML
     )
@@ -126,7 +126,7 @@ public object Opds1Sniffer : FormatSniffer {
         format: Format,
         source: Readable
     ): Try<Format, ReadError> {
-        if (format.hasMoreThan(XmlSpecification) || !source.canReadWholeBlob()) {
+        if (format.hasMoreThan(Specification.Xml) || !source.canReadWholeBlob()) {
             return Try.success(format)
         }
 
@@ -148,25 +148,25 @@ public object Opds1Sniffer : FormatSniffer {
     }
 
     private val opds1CatalogFormat = Format(
-        specification = FormatSpecification(XmlSpecification, Opds1CatalogSpecification),
+        specification = FormatSpecification(Specification.Xml, Specification.Opds1Catalog),
         mediaType = MediaType.OPDS1,
         fileExtension = FileExtension("xml")
     )
 
     private val opds1NavigationFeedFormat = Format(
-        specification = FormatSpecification(XmlSpecification, Opds1CatalogSpecification),
+        specification = FormatSpecification(Specification.Xml, Specification.Opds1Catalog),
         mediaType = MediaType.OPDS1_NAVIGATION_FEED,
         fileExtension = FileExtension("xml")
     )
 
     private val opds1AcquisitionFeedFormat = Format(
-        specification = FormatSpecification(XmlSpecification, Opds1CatalogSpecification),
+        specification = FormatSpecification(Specification.Xml, Specification.Opds1Catalog),
         mediaType = MediaType.OPDS1_ACQUISITION_FEED,
         fileExtension = FileExtension("xml")
     )
 
     private val opds1EntryFormat = Format(
-        specification = FormatSpecification(XmlSpecification, Opds1EntrySpecification),
+        specification = FormatSpecification(Specification.Xml, Specification.Opds1Entry),
         mediaType = MediaType.OPDS1_ENTRY,
         fileExtension = FileExtension("xml")
     )
@@ -201,7 +201,7 @@ public object Opds2Sniffer : FormatSniffer {
         format: Format,
         source: Readable
     ): Try<Format, ReadError> {
-        if (format.hasMoreThan(JsonSpecification) || !source.canReadWholeBlob()) {
+        if (format.hasMoreThan(Specification.Json) || !source.canReadWholeBlob()) {
             return Try.success(format)
         }
 
@@ -243,19 +243,19 @@ public object Opds2Sniffer : FormatSniffer {
     }
 
     private val opdsAuthenticationFormat = Format(
-        specification = FormatSpecification(JsonSpecification, OpdsAuthenticationSpecification),
+        specification = FormatSpecification(Specification.Json, Specification.OpdsAuthentication),
         mediaType = MediaType.OPDS_AUTHENTICATION,
         fileExtension = FileExtension("json")
     )
 
     private val opds2CatalogFormat = Format(
-        specification = FormatSpecification(JsonSpecification, Opds2CatalogSpecification),
+        specification = FormatSpecification(Specification.Json, Specification.Opds2Catalog),
         mediaType = MediaType.OPDS2,
         fileExtension = FileExtension("json")
     )
 
     private val opds2PublicationFormat = Format(
-        specification = FormatSpecification(JsonSpecification, Opds2PublicationSpecification),
+        specification = FormatSpecification(Specification.Json, Specification.Opds2Publication),
         mediaType = MediaType.OPDS2_PUBLICATION,
         fileExtension = FileExtension("json")
     )
@@ -281,7 +281,7 @@ public object LcpLicenseSniffer : FormatSniffer {
         source: Readable
     ): Try<Format, ReadError> {
         if (
-            format.hasMoreThan(JsonSpecification) ||
+            format.hasMoreThan(Specification.Json) ||
             !source.canReadWholeBlob()
         ) {
             return Try.success(format)
@@ -296,7 +296,7 @@ public object LcpLicenseSniffer : FormatSniffer {
     }
 
     private val lcplFormat = Format(
-        specification = FormatSpecification(JsonSpecification, LcpLicenseSpecification),
+        specification = FormatSpecification(Specification.Json, Specification.LcpLicense),
         mediaType = MediaType.LCP_LICENSE_DOCUMENT,
         fileExtension = FileExtension("lcpl")
     )
@@ -313,7 +313,7 @@ public object BitmapSniffer : FormatSniffer {
             hints.hasMediaType("image/avif")
         ) {
             return Format(
-                specification = FormatSpecification(AvifSpecification),
+                specification = FormatSpecification(Specification.Avif),
                 mediaType = MediaType.AVIF,
                 fileExtension = FileExtension("avif")
             )
@@ -323,7 +323,7 @@ public object BitmapSniffer : FormatSniffer {
             hints.hasMediaType("image/bmp", "image/x-bmp")
         ) {
             return Format(
-                specification = FormatSpecification(BmpSpecification),
+                specification = FormatSpecification(Specification.Bmp),
                 mediaType = MediaType.BMP,
                 fileExtension = FileExtension("bmp")
             )
@@ -333,7 +333,7 @@ public object BitmapSniffer : FormatSniffer {
             hints.hasMediaType("image/gif")
         ) {
             return Format(
-                specification = FormatSpecification(GifSpecification),
+                specification = FormatSpecification(Specification.Gif),
                 mediaType = MediaType.GIF,
                 fileExtension = FileExtension("gif")
             )
@@ -343,7 +343,7 @@ public object BitmapSniffer : FormatSniffer {
             hints.hasMediaType("image/jpeg")
         ) {
             return Format(
-                specification = FormatSpecification(JpegSpecification),
+                specification = FormatSpecification(Specification.Jpeg),
                 mediaType = MediaType.JPEG,
                 fileExtension = FileExtension("jpg")
             )
@@ -353,7 +353,7 @@ public object BitmapSniffer : FormatSniffer {
             hints.hasMediaType("image/jxl")
         ) {
             return Format(
-                specification = FormatSpecification(JxlSpecification),
+                specification = FormatSpecification(Specification.Jxl),
                 mediaType = MediaType.JXL,
                 fileExtension = FileExtension("jxl")
             )
@@ -363,7 +363,7 @@ public object BitmapSniffer : FormatSniffer {
             hints.hasMediaType("image/png")
         ) {
             return Format(
-                specification = FormatSpecification(PngSpecification),
+                specification = FormatSpecification(Specification.Png),
                 mediaType = MediaType.PNG,
                 fileExtension = FileExtension("png")
             )
@@ -373,7 +373,7 @@ public object BitmapSniffer : FormatSniffer {
             hints.hasMediaType("image/tiff", "image/tiff-fx")
         ) {
             return Format(
-                specification = FormatSpecification(TiffSpecification),
+                specification = FormatSpecification(Specification.Tiff),
                 mediaType = MediaType.TIFF,
                 fileExtension = FileExtension("tiff")
             )
@@ -383,7 +383,7 @@ public object BitmapSniffer : FormatSniffer {
             hints.hasMediaType("image/webp")
         ) {
             return Format(
-                specification = FormatSpecification(WebpSpecification),
+                specification = FormatSpecification(Specification.Webp),
                 mediaType = MediaType.WEBP,
                 fileExtension = FileExtension("webp")
             )
@@ -400,7 +400,7 @@ public object AudioSniffer : FormatSniffer {
             hints.hasFileExtension("aac")
         ) {
             return Format(
-                specification = FormatSpecification(AacSpecification),
+                specification = FormatSpecification(Specification.Aac),
                 mediaType = MediaType.AAC,
                 fileExtension = FileExtension("aac")
             )
@@ -410,7 +410,7 @@ public object AudioSniffer : FormatSniffer {
             hints.hasFileExtension("aiff")
         ) {
             return Format(
-                specification = FormatSpecification(AiffSpecification),
+                specification = FormatSpecification(Specification.Aiff),
                 mediaType = MediaType.AIFF,
                 fileExtension = FileExtension("aiff")
             )
@@ -420,7 +420,7 @@ public object AudioSniffer : FormatSniffer {
             hints.hasFileExtension("flac")
         ) {
             return Format(
-                specification = FormatSpecification(FlacSpecification),
+                specification = FormatSpecification(Specification.Flac),
                 mediaType = MediaType.FLAC,
                 fileExtension = FileExtension("flac")
             )
@@ -430,7 +430,7 @@ public object AudioSniffer : FormatSniffer {
             hints.hasFileExtension("m4a", "m4b", "alac")
         ) {
             return Format(
-                specification = FormatSpecification(Mp4Specification),
+                specification = FormatSpecification(Specification.Mp4),
                 mediaType = MediaType.MP4,
                 fileExtension = FileExtension("m4a")
             )
@@ -440,7 +440,7 @@ public object AudioSniffer : FormatSniffer {
             hints.hasFileExtension("mp3")
         ) {
             return Format(
-                specification = FormatSpecification(Mp3Specification),
+                specification = FormatSpecification(Specification.Mp3),
                 mediaType = MediaType.MP3,
                 fileExtension = FileExtension("mp3")
             )
@@ -450,7 +450,7 @@ public object AudioSniffer : FormatSniffer {
             hints.hasFileExtension("ogg", "oga")
         ) {
             return Format(
-                specification = FormatSpecification(OggSpecification),
+                specification = FormatSpecification(Specification.Ogg),
                 mediaType = MediaType.OGG,
                 fileExtension = FileExtension("oga")
             )
@@ -460,7 +460,7 @@ public object AudioSniffer : FormatSniffer {
             hints.hasFileExtension("opus")
         ) {
             return Format(
-                specification = FormatSpecification(OpusSpecification),
+                specification = FormatSpecification(Specification.Opus),
                 mediaType = MediaType.OPUS,
                 fileExtension = FileExtension("opus")
             )
@@ -470,7 +470,7 @@ public object AudioSniffer : FormatSniffer {
             hints.hasFileExtension("wav")
         ) {
             return Format(
-                specification = FormatSpecification(WavSpecification),
+                specification = FormatSpecification(Specification.Wav),
                 mediaType = MediaType.WAV,
                 fileExtension = FileExtension("wav")
             )
@@ -480,7 +480,7 @@ public object AudioSniffer : FormatSniffer {
             hints.hasFileExtension("webm")
         ) {
             return Format(
-                specification = FormatSpecification(WebmSpecification),
+                specification = FormatSpecification(Specification.Webm),
                 mediaType = MediaType.WEBM_AUDIO,
                 fileExtension = FileExtension("webm")
             )
@@ -515,7 +515,7 @@ public object RwpmSniffer : FormatSniffer {
         source: Readable
     ): Try<Format, ReadError> {
         if (
-            format.hasMoreThan(JsonSpecification) ||
+            format.hasMoreThan(Specification.Json) ||
             !source.canReadWholeBlob()
         ) {
             return Try.success(format)
@@ -543,19 +543,19 @@ public object RwpmSniffer : FormatSniffer {
     }
 
     private val rwpmFormat = Format(
-        specification = FormatSpecification(JsonSpecification, RwpmSpecification),
+        specification = FormatSpecification(Specification.Json, Specification.Rwpm),
         mediaType = MediaType.READIUM_WEBPUB_MANIFEST,
         fileExtension = FileExtension("json")
     )
 
     private val rwpmAudioFormat = Format(
-        specification = FormatSpecification(JsonSpecification, RwpmSpecification),
+        specification = FormatSpecification(Specification.Json, Specification.Rwpm),
         mediaType = MediaType.READIUM_AUDIOBOOK_MANIFEST,
         fileExtension = FileExtension("json")
     )
 
     private val rwpmDivinaFormat = Format(
-        specification = FormatSpecification(JsonSpecification, RwpmSpecification),
+        specification = FormatSpecification(Specification.Json, Specification.Rwpm),
         mediaType = MediaType.DIVINA_MANIFEST,
         fileExtension = FileExtension("json")
     )
@@ -609,7 +609,7 @@ public object RpfSniffer : FormatSniffer {
         container: Container<Readable>
     ): Try<Format, ReadError> {
         if (
-            format.hasMoreThan(ZipSpecification, RpfSpecification, LcpSpecification)
+            format.hasMoreThan(Specification.Zip, Specification.Rpf, Specification.Lcp)
         ) {
             return Try.success(format)
         }
@@ -635,7 +635,7 @@ public object RpfSniffer : FormatSniffer {
             }
             manifest.conformsTo(Publication.Profile.DIVINA) -> {
                 if (isLcpProtected) {
-                    rpfDivinaFormat.addSpecifications(LcpSpecification)
+                    rpfDivinaFormat.addSpecifications(Specification.Lcp)
                 } else {
                     rpfDivinaFormat
                 }
@@ -649,7 +649,7 @@ public object RpfSniffer : FormatSniffer {
             }
             else ->
                 if (isLcpProtected) {
-                    rpfFormat.addSpecifications(LcpSpecification)
+                    rpfFormat.addSpecifications(Specification.Lcp)
                 } else {
                     rpfFormat
                 }
@@ -663,31 +663,31 @@ public object RpfSniffer : FormatSniffer {
         .any { it.properties.encryption?.scheme == "http://readium.org/2014/01/lcp" }
 
     private val rpfFormat = Format(
-        specification = FormatSpecification(ZipSpecification, RpfSpecification),
+        specification = FormatSpecification(Specification.Zip, Specification.Rpf),
         mediaType = MediaType.READIUM_WEBPUB,
         fileExtension = FileExtension("webpub")
     )
 
     private val rpfAudioFormat = Format(
-        specification = FormatSpecification(ZipSpecification, RpfSpecification),
+        specification = FormatSpecification(Specification.Zip, Specification.Rpf),
         mediaType = MediaType.READIUM_AUDIOBOOK,
         fileExtension = FileExtension("audiobook")
     )
 
     private val rpfDivinaFormat = Format(
-        specification = FormatSpecification(ZipSpecification, RpfSpecification),
+        specification = FormatSpecification(Specification.Zip, Specification.Rpf),
         mediaType = MediaType.DIVINA,
         fileExtension = FileExtension("divina")
     )
 
     private val lcpaFormat = Format(
-        specification = FormatSpecification(ZipSpecification, RpfSpecification, LcpSpecification),
+        specification = FormatSpecification(Specification.Zip, Specification.Rpf, Specification.Lcp),
         mediaType = MediaType.LCP_PROTECTED_AUDIOBOOK,
         fileExtension = FileExtension("lcpa")
     )
 
     private val lcpdfFormat = Format(
-        specification = FormatSpecification(ZipSpecification, RpfSpecification, LcpSpecification),
+        specification = FormatSpecification(Specification.Zip, Specification.Rpf, Specification.Lcp),
         mediaType = MediaType.LCP_PROTECTED_PDF,
         fileExtension = FileExtension("lcpdf")
     )
@@ -700,7 +700,7 @@ public object W3cWpubSniffer : FormatSniffer {
         format: Format,
         source: Readable
     ): Try<Format, ReadError> {
-        if (format.hasMoreThan(JsonSpecification) || !source.canReadWholeBlob()) {
+        if (format.hasMoreThan(Specification.Json) || !source.canReadWholeBlob()) {
             return Try.success(format)
         }
 
@@ -717,8 +717,8 @@ public object W3cWpubSniffer : FormatSniffer {
             return Try.success(
                 Format(
                     specification = FormatSpecification(
-                        JsonSpecification,
-                        W3cPubManifestSpecification
+                        Specification.Json,
+                        Specification.W3cPubManifest
                     ),
                     mediaType = MediaType.W3C_WPUB_MANIFEST,
                     fileExtension = FileExtension("json")
@@ -753,7 +753,7 @@ public object EpubSniffer : FormatSniffer {
         format: Format,
         container: Container<Readable>
     ): Try<Format, ReadError> {
-        if (format.hasMoreThan(ZipSpecification)) {
+        if (format.hasMoreThan(Specification.Zip)) {
             return Try.success(format)
         }
 
@@ -772,7 +772,7 @@ public object EpubSniffer : FormatSniffer {
     }
 
     private val epubFormatSpecification = Format(
-        specification = FormatSpecification(ZipSpecification, EpubSpecification),
+        specification = FormatSpecification(Specification.Zip, Specification.Epub),
         mediaType = MediaType.EPUB,
         fileExtension = FileExtension("epub")
     )
@@ -803,7 +803,7 @@ public object LpfSniffer : FormatSniffer {
         format: Format,
         container: Container<Readable>
     ): Try<Format, ReadError> {
-        if (format.hasMoreThan(ZipSpecification)) {
+        if (format.hasMoreThan(Specification.Zip)) {
             return Try.success(format)
         }
 
@@ -829,7 +829,7 @@ public object LpfSniffer : FormatSniffer {
     }
 
     private val lpfFormat = Format(
-        specification = FormatSpecification(ZipSpecification, LpfSpecification),
+        specification = FormatSpecification(Specification.Zip, Specification.Lpf),
         mediaType = MediaType.LPF,
         fileExtension = FileExtension("lpf")
     )
@@ -852,7 +852,7 @@ public object RarSniffer : FormatSniffer {
             hints.hasMediaType("application/x-rar-compressed")
         ) {
             return Format(
-                specification = FormatSpecification(RarSpecification),
+                specification = FormatSpecification(Specification.Rar),
                 mediaType = MediaType.RAR,
                 fileExtension = FileExtension("rar")
             )
@@ -874,7 +874,7 @@ public object ZipSniffer : FormatSniffer {
             hints.hasFileExtension("zip")
         ) {
             return Format(
-                specification = FormatSpecification(ZipSpecification),
+                specification = FormatSpecification(Specification.Zip),
                 mediaType = MediaType.ZIP,
                 fileExtension = FileExtension("zip")
             )
@@ -945,7 +945,7 @@ public object ArchiveSniffer : FormatSniffer {
             )
         ) {
             return Format(
-                specification = FormatSpecification(ZipSpecification, InformalComicSpecification),
+                specification = FormatSpecification(Specification.Zip, Specification.InformalComic),
                 mediaType = MediaType.CBZ,
                 fileExtension = FileExtension("cbz")
             )
@@ -957,7 +957,7 @@ public object ArchiveSniffer : FormatSniffer {
             hints.hasMediaType("application/x-cbr")
         ) {
             return Format(
-                specification = FormatSpecification(RarSpecification, InformalComicSpecification),
+                specification = FormatSpecification(Specification.Rar, Specification.InformalComic),
                 mediaType = MediaType.CBR,
                 fileExtension = FileExtension("cbr")
             )
@@ -966,8 +966,8 @@ public object ArchiveSniffer : FormatSniffer {
         if (hints.hasFileExtension("zab")) {
             return Format(
                 specification = FormatSpecification(
-                    ZipSpecification,
-                    InformalAudiobookSpecification
+                    Specification.Zip,
+                    Specification.InformalAudiobook
                 ),
                 mediaType = MediaType.ZAB,
                 fileExtension = FileExtension("zab")
@@ -981,7 +981,7 @@ public object ArchiveSniffer : FormatSniffer {
         format: Format,
         container: Container<Readable>
     ): Try<Format, ReadError> {
-        if (format.hasMoreThan(ZipSpecification, RarSpecification)) {
+        if (format.hasMoreThan(Specification.Zip, Specification.Rar)) {
             return Try.success(format)
         }
 
@@ -1003,14 +1003,14 @@ public object ArchiveSniffer : FormatSniffer {
 
         if (archiveContainsOnlyExtensions(cbzExtensions)) {
             val mediaType =
-                if (format.conformsTo(RarSpecification)) {
+                if (format.conformsTo(Specification.Rar)) {
                     MediaType.CBR
                 } else {
                     MediaType.CBZ
                 }
 
             val extension =
-                if (format.conformsTo(RarSpecification)) {
+                if (format.conformsTo(Specification.Rar)) {
                     FileExtension("cbr")
                 } else {
                     FileExtension("cbz")
@@ -1018,7 +1018,7 @@ public object ArchiveSniffer : FormatSniffer {
 
             return Try.success(
                 Format(
-                    specification = format.specification + InformalComicSpecification,
+                    specification = format.specification + Specification.InformalComic,
                     mediaType = mediaType,
                     fileExtension = extension
                 )
@@ -1027,14 +1027,14 @@ public object ArchiveSniffer : FormatSniffer {
 
         if (archiveContainsOnlyExtensions(zabExtensions)) {
             val mediaType =
-                if (format.conformsTo(ZipSpecification)) {
+                if (format.conformsTo(Specification.Zip)) {
                     MediaType.ZAB
                 } else {
                     format.mediaType
                 }
 
             val extension =
-                if (format.conformsTo(ZipSpecification)) {
+                if (format.conformsTo(Specification.Zip)) {
                     FileExtension("zab")
                 } else {
                     format.fileExtension
@@ -1042,7 +1042,7 @@ public object ArchiveSniffer : FormatSniffer {
 
             return Try.success(
                 Format(
-                    specification = format.specification + InformalAudiobookSpecification,
+                    specification = format.specification + Specification.InformalAudiobook,
                     mediaType = mediaType,
                     fileExtension = extension
                 )
@@ -1090,7 +1090,7 @@ public object PdfSniffer : FormatSniffer {
     }
 
     private val pdfFormat = Format(
-        specification = FormatSpecification(PdfSpecification),
+        specification = FormatSpecification(Specification.Pdf),
         mediaType = MediaType.PDF,
         fileExtension = FileExtension("pdf")
     )
@@ -1105,7 +1105,7 @@ public object JsonSniffer : FormatSniffer {
             hints.hasMediaType("application/json")
         ) {
             return Format(
-                specification = FormatSpecification(JsonSpecification),
+                specification = FormatSpecification(Specification.Json),
                 mediaType = MediaType.JSON,
                 fileExtension = FileExtension("json")
             )
@@ -1113,7 +1113,10 @@ public object JsonSniffer : FormatSniffer {
 
         if (hints.hasMediaType("application/problem+json")) {
             return Format(
-                specification = FormatSpecification(JsonSpecification, ProblemDetailsSpecification),
+                specification = FormatSpecification(
+                    Specification.Json,
+                    Specification.ProblemDetails
+                ),
                 mediaType = MediaType.JSON_PROBLEM_DETAILS,
                 fileExtension = FileExtension("json")
             )
@@ -1137,7 +1140,7 @@ public object JsonSniffer : FormatSniffer {
         )?.let {
             return Try.success(
                 Format(
-                    specification = FormatSpecification(JsonSpecification),
+                    specification = FormatSpecification(Specification.Json),
                     mediaType = MediaType.JSON,
                     fileExtension = FileExtension("json")
                 )
@@ -1158,15 +1161,15 @@ public object EpubDrmSniffer : FormatSniffer {
         container: Container<Readable>
     ): Try<Format, ReadError> {
         if (
-            !format.conformsTo(EpubSpecification) ||
-            format.conformsTo(AdeptSpecification) ||
-            format.conformsTo(LcpSpecification)
+            !format.conformsTo(Specification.Epub) ||
+            format.conformsTo(Specification.Adept) ||
+            format.conformsTo(Specification.Lcp)
         ) {
             return Try.success(format)
         }
 
         if (RelativeUrl("META-INF/license.lcpl")!! in container) {
-            return Try.success(format.addSpecifications(LcpSpecification))
+            return Try.success(format.addSpecifications(Specification.Lcp))
         }
 
         val encryptionDocument = container[Url("META-INF/encryption.xml")!!]
@@ -1181,14 +1184,14 @@ public object EpubDrmSniffer : FormatSniffer {
             ?.flatMap { it.get("RetrievalMethod", EpubEncryption.SIG) }
             ?.any { it.getAttr("URI") == "license.lcpl#/encryption/content_key" }
             ?.takeIf { it }
-            ?.let { return Try.success(format.addSpecifications(LcpSpecification)) }
+            ?.let { return Try.success(format.addSpecifications(Specification.Lcp)) }
 
         encryptionDocument
             ?.get("EncryptedData", EpubEncryption.ENC)
             ?.flatMap { it.get("KeyInfo", EpubEncryption.SIG) }
             ?.flatMap { it.get("resource", "http://ns.adobe.com/adept") }
             ?.takeIf { it.isNotEmpty() }
-            ?.let { return Try.success(format.addSpecifications(AdeptSpecification)) }
+            ?.let { return Try.success(format.addSpecifications(Specification.Adept)) }
 
         container[Url("META-INF/rights.xml")!!]
             ?.readDecodeOrElse(
@@ -1196,7 +1199,7 @@ public object EpubDrmSniffer : FormatSniffer {
                 recover = { null }
             )
             ?.takeIf { it.namespace == "http://ns.adobe.com/adept" }
-            ?.let { return Try.success(format.addSpecifications(AdeptSpecification)) }
+            ?.let { return Try.success(format.addSpecifications(Specification.Adept)) }
 
         return Try.success(format)
     }
@@ -1212,7 +1215,7 @@ public object CssSniffer : FormatSniffer {
             hints.hasMediaType("text/css")
         ) {
             return Format(
-                specification = FormatSpecification(CssSpecification),
+                specification = FormatSpecification(Specification.Css),
                 mediaType = MediaType.CSS,
                 fileExtension = FileExtension("css")
             )
@@ -1233,7 +1236,7 @@ public object JavaScriptSniffer : FormatSniffer {
             hints.hasMediaType("application/javascript")
         ) {
             return Format(
-                specification = FormatSpecification(JavaScriptSpecification),
+                specification = FormatSpecification(Specification.JavaScript),
                 mediaType = MediaType.JAVASCRIPT,
                 fileExtension = FileExtension("js")
             )
diff --git a/readium/shared/src/main/java/org/readium/r2/shared/util/zip/FileZipArchiveProvider.kt b/readium/shared/src/main/java/org/readium/r2/shared/util/zip/FileZipArchiveProvider.kt
index 4989b5c5dc..f75d4605c9 100644
--- a/readium/shared/src/main/java/org/readium/r2/shared/util/zip/FileZipArchiveProvider.kt
+++ b/readium/shared/src/main/java/org/readium/r2/shared/util/zip/FileZipArchiveProvider.kt
@@ -19,7 +19,7 @@ import org.readium.r2.shared.util.data.Container
 import org.readium.r2.shared.util.data.ReadError
 import org.readium.r2.shared.util.file.FileSystemError
 import org.readium.r2.shared.util.format.Format
-import org.readium.r2.shared.util.format.ZipSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.resource.Resource
 
 /**
@@ -54,7 +54,7 @@ internal class FileZipArchiveProvider {
         format: Format,
         file: File
     ): Try<Container<Resource>, ArchiveOpener.OpenError> {
-        if (!format.conformsTo(ZipSpecification)) {
+        if (!format.conformsTo(Specification.Zip)) {
             return Try.failure(
                 ArchiveOpener.OpenError.FormatNotSupported(format)
             )
diff --git a/readium/shared/src/main/java/org/readium/r2/shared/util/zip/StreamingZipArchiveProvider.kt b/readium/shared/src/main/java/org/readium/r2/shared/util/zip/StreamingZipArchiveProvider.kt
index cdc63c5864..8bacbd26a5 100644
--- a/readium/shared/src/main/java/org/readium/r2/shared/util/zip/StreamingZipArchiveProvider.kt
+++ b/readium/shared/src/main/java/org/readium/r2/shared/util/zip/StreamingZipArchiveProvider.kt
@@ -19,7 +19,7 @@ import org.readium.r2.shared.util.data.ReadError
 import org.readium.r2.shared.util.data.ReadException
 import org.readium.r2.shared.util.data.Readable
 import org.readium.r2.shared.util.format.Format
-import org.readium.r2.shared.util.format.ZipSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.resource.Resource
 import org.readium.r2.shared.util.toUrl
 import org.readium.r2.shared.util.zip.compress.archivers.zip.ZipFile
@@ -46,7 +46,7 @@ internal class StreamingZipArchiveProvider {
         format: Format,
         source: Readable
     ): Try<Container<Resource>, ArchiveOpener.OpenError> {
-        if (!format.conformsTo(ZipSpecification)) {
+        if (!format.conformsTo(Specification.Zip)) {
             return Try.failure(
                 ArchiveOpener.OpenError.FormatNotSupported(format)
             )
diff --git a/readium/shared/src/main/java/org/readium/r2/shared/util/zip/ZipArchiveOpener.kt b/readium/shared/src/main/java/org/readium/r2/shared/util/zip/ZipArchiveOpener.kt
index 84f4f56c06..a5bc1d7558 100644
--- a/readium/shared/src/main/java/org/readium/r2/shared/util/zip/ZipArchiveOpener.kt
+++ b/readium/shared/src/main/java/org/readium/r2/shared/util/zip/ZipArchiveOpener.kt
@@ -13,7 +13,7 @@ import org.readium.r2.shared.util.asset.ContainerAsset
 import org.readium.r2.shared.util.data.Readable
 import org.readium.r2.shared.util.format.Format
 import org.readium.r2.shared.util.format.FormatSpecification
-import org.readium.r2.shared.util.format.ZipSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.mediatype.MediaType
 import org.readium.r2.shared.util.resource.Resource
 
@@ -44,7 +44,7 @@ public class ZipArchiveOpener : ArchiveOpener {
         return container.map {
             ContainerAsset(
                 format = Format(
-                    specification = FormatSpecification(ZipSpecification),
+                    specification = FormatSpecification(Specification.Zip),
                     mediaType = MediaType.ZIP,
                     fileExtension = FileExtension("zip")
                 ),
diff --git a/readium/shared/src/test/java/org/readium/r2/shared/util/asset/AssetSnifferTest.kt b/readium/shared/src/test/java/org/readium/r2/shared/util/asset/AssetSnifferTest.kt
index 19633a086a..ed773439f7 100644
--- a/readium/shared/src/test/java/org/readium/r2/shared/util/asset/AssetSnifferTest.kt
+++ b/readium/shared/src/test/java/org/readium/r2/shared/util/asset/AssetSnifferTest.kt
@@ -18,40 +18,10 @@ import org.readium.r2.shared.util.Try
 import org.readium.r2.shared.util.checkSuccess
 import org.readium.r2.shared.util.data.EmptyContainer
 import org.readium.r2.shared.util.file.FileResource
-import org.readium.r2.shared.util.format.AvifSpecification
-import org.readium.r2.shared.util.format.BmpSpecification
-import org.readium.r2.shared.util.format.CssSpecification
-import org.readium.r2.shared.util.format.EpubSpecification
 import org.readium.r2.shared.util.format.Format
 import org.readium.r2.shared.util.format.FormatHints
 import org.readium.r2.shared.util.format.FormatSpecification
-import org.readium.r2.shared.util.format.GifSpecification
-import org.readium.r2.shared.util.format.HtmlSpecification
-import org.readium.r2.shared.util.format.InformalAudiobookSpecification
-import org.readium.r2.shared.util.format.InformalComicSpecification
-import org.readium.r2.shared.util.format.JavaScriptSpecification
-import org.readium.r2.shared.util.format.JpegSpecification
-import org.readium.r2.shared.util.format.JsonSpecification
-import org.readium.r2.shared.util.format.JxlSpecification
-import org.readium.r2.shared.util.format.LcpLicenseSpecification
-import org.readium.r2.shared.util.format.LcpSpecification
-import org.readium.r2.shared.util.format.LpfSpecification
-import org.readium.r2.shared.util.format.Opds1CatalogSpecification
-import org.readium.r2.shared.util.format.Opds1EntrySpecification
-import org.readium.r2.shared.util.format.Opds2CatalogSpecification
-import org.readium.r2.shared.util.format.Opds2PublicationSpecification
-import org.readium.r2.shared.util.format.OpdsAuthenticationSpecification
-import org.readium.r2.shared.util.format.PdfSpecification
-import org.readium.r2.shared.util.format.PngSpecification
-import org.readium.r2.shared.util.format.ProblemDetailsSpecification
-import org.readium.r2.shared.util.format.RarSpecification
-import org.readium.r2.shared.util.format.RpfSpecification
-import org.readium.r2.shared.util.format.RwpmSpecification
-import org.readium.r2.shared.util.format.TiffSpecification
-import org.readium.r2.shared.util.format.W3cPubManifestSpecification
-import org.readium.r2.shared.util.format.WebpSpecification
-import org.readium.r2.shared.util.format.XmlSpecification
-import org.readium.r2.shared.util.format.ZipSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.mediatype.MediaType
 import org.readium.r2.shared.util.resource.Resource
 import org.readium.r2.shared.util.resource.StringResource
@@ -83,21 +53,21 @@ class AssetSnifferTest {
 
     private val epubFormat =
         Format(
-            specification = FormatSpecification(ZipSpecification, EpubSpecification),
+            specification = FormatSpecification(Specification.Zip, Specification.Epub),
             mediaType = MediaType.EPUB,
             fileExtension = FileExtension("epub")
         )
 
     private val audiobookFormat =
         Format(
-            specification = FormatSpecification(ZipSpecification, RpfSpecification),
+            specification = FormatSpecification(Specification.Zip, Specification.Rpf),
             mediaType = MediaType.READIUM_AUDIOBOOK,
             fileExtension = FileExtension("audiobook")
         )
 
     private val audiobookManifestFormat =
         Format(
-            specification = FormatSpecification(JsonSpecification, RwpmSpecification),
+            specification = FormatSpecification(Specification.Json, Specification.Rwpm),
             mediaType = MediaType.READIUM_AUDIOBOOK_MANIFEST,
             fileExtension = FileExtension("json")
         )
@@ -210,7 +180,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff BMP`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(BmpSpecification),
+            specification = FormatSpecification(Specification.Bmp),
             mediaType = MediaType.BMP,
             fileExtension = FileExtension("bmp")
         )
@@ -224,13 +194,13 @@ class AssetSnifferTest {
     @Test
     fun `sniff CBZ`() = runBlocking {
         val cbzFormat = Format(
-            specification = FormatSpecification(ZipSpecification, InformalComicSpecification),
+            specification = FormatSpecification(Specification.Zip, Specification.InformalComic),
             mediaType = MediaType.CBZ,
             fileExtension = FileExtension("cbz")
         )
 
         val cbrFormat = Format(
-            specification = FormatSpecification(RarSpecification, InformalComicSpecification),
+            specification = FormatSpecification(Specification.Rar, Specification.InformalComic),
             mediaType = MediaType.CBR,
             fileExtension = FileExtension("cbr")
         )
@@ -260,7 +230,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff DiViNa`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(ZipSpecification, RpfSpecification),
+            specification = FormatSpecification(Specification.Zip, Specification.Rpf),
             mediaType = MediaType.DIVINA,
             fileExtension = FileExtension("divina")
         )
@@ -282,7 +252,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff DiViNa manifest`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(JsonSpecification, RwpmSpecification),
+            specification = FormatSpecification(Specification.Json, Specification.Rwpm),
             mediaType = MediaType.DIVINA_MANIFEST,
             fileExtension = FileExtension("json")
         )
@@ -316,7 +286,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff AVIF`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(AvifSpecification),
+            specification = FormatSpecification(Specification.Avif),
             mediaType = MediaType.AVIF,
             fileExtension = FileExtension("avif")
         )
@@ -328,7 +298,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff GIF`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(GifSpecification),
+            specification = FormatSpecification(Specification.Gif),
             mediaType = MediaType.GIF,
             fileExtension = FileExtension("gif")
         )
@@ -340,7 +310,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff HTML`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(HtmlSpecification),
+            specification = FormatSpecification(Specification.Html),
             mediaType = MediaType.HTML,
             fileExtension = FileExtension("html")
         )
@@ -369,7 +339,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff XHTML`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(XmlSpecification, HtmlSpecification),
+            specification = FormatSpecification(Specification.Xml, Specification.Html),
             mediaType = MediaType.XHTML,
             fileExtension = FileExtension("xhtml")
         )
@@ -395,7 +365,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff JPEG`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(JpegSpecification),
+            specification = FormatSpecification(Specification.Jpeg),
             mediaType = MediaType.JPEG,
             fileExtension = FileExtension("jpg")
         )
@@ -412,7 +382,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff JXL`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(JxlSpecification),
+            specification = FormatSpecification(Specification.Jxl),
             mediaType = MediaType.JXL,
             fileExtension = FileExtension("jxl")
         )
@@ -424,7 +394,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff RAR`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(RarSpecification),
+            specification = FormatSpecification(Specification.Rar),
             mediaType = MediaType.RAR,
             fileExtension = FileExtension("rar")
         )
@@ -450,7 +420,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff OPDS 1 feed`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(XmlSpecification, Opds1CatalogSpecification),
+            specification = FormatSpecification(Specification.Xml, Specification.Opds1Catalog),
             mediaType = MediaType.OPDS1,
             fileExtension = FileExtension("xml")
         )
@@ -476,7 +446,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff OPDS 1 entry`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(XmlSpecification, Opds1EntrySpecification),
+            specification = FormatSpecification(Specification.Xml, Specification.Opds1Entry),
             mediaType = MediaType.OPDS1_ENTRY,
             fileExtension = FileExtension("xml")
         )
@@ -494,7 +464,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff OPDS 2 feed`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(JsonSpecification, Opds2CatalogSpecification),
+            specification = FormatSpecification(Specification.Json, Specification.Opds2Catalog),
             mediaType = MediaType.OPDS2,
             fileExtension = FileExtension("json")
         )
@@ -512,7 +482,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff OPDS 2 publication`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(JsonSpecification, Opds2PublicationSpecification),
+            specification = FormatSpecification(Specification.Json, Specification.Opds2Publication),
             mediaType = MediaType.OPDS2_PUBLICATION,
             fileExtension = FileExtension("json")
         )
@@ -530,7 +500,10 @@ class AssetSnifferTest {
     @Test
     fun `sniff OPDS authentication document`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(JsonSpecification, OpdsAuthenticationSpecification),
+            specification = FormatSpecification(
+                Specification.Json,
+                Specification.OpdsAuthentication
+            ),
             mediaType = MediaType.OPDS_AUTHENTICATION,
             fileExtension = FileExtension("json")
         )
@@ -553,9 +526,9 @@ class AssetSnifferTest {
     fun `sniff LCP protected audiobook`() = runBlocking {
         val format = Format(
             specification = FormatSpecification(
-                ZipSpecification,
-                RpfSpecification,
-                LcpSpecification
+                Specification.Zip,
+                Specification.Rpf,
+                Specification.Lcp
             ),
             mediaType = MediaType.LCP_PROTECTED_AUDIOBOOK,
             fileExtension = FileExtension("lcpa")
@@ -579,9 +552,9 @@ class AssetSnifferTest {
     fun `sniff LCP protected PDF`() = runBlocking {
         val format = Format(
             specification = FormatSpecification(
-                ZipSpecification,
-                RpfSpecification,
-                LcpSpecification
+                Specification.Zip,
+                Specification.Rpf,
+                Specification.Lcp
             ),
             mediaType = MediaType.LCP_PROTECTED_PDF,
             fileExtension = FileExtension("lcpdf")
@@ -604,7 +577,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff LCP license document`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(JsonSpecification, LcpLicenseSpecification),
+            specification = FormatSpecification(Specification.Json, Specification.LcpLicense),
             mediaType = MediaType.LCP_LICENSE_DOCUMENT,
             fileExtension = FileExtension("lcpl")
         )
@@ -626,7 +599,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff LPF`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(ZipSpecification, LpfSpecification),
+            specification = FormatSpecification(Specification.Zip, Specification.Lpf),
             mediaType = MediaType.LPF,
             fileExtension = FileExtension("lpf")
         )
@@ -652,7 +625,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff PDF`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(PdfSpecification),
+            specification = FormatSpecification(Specification.Pdf),
             mediaType = MediaType.PDF,
             fileExtension = FileExtension("pdf")
         )
@@ -674,7 +647,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff PNG`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(PngSpecification),
+            specification = FormatSpecification(Specification.Png),
             mediaType = MediaType.PNG,
             fileExtension = FileExtension("png")
         )
@@ -686,7 +659,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff TIFF`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(TiffSpecification),
+            specification = FormatSpecification(Specification.Tiff),
             mediaType = MediaType.TIFF,
             fileExtension = FileExtension("tiff")
         )
@@ -703,7 +676,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff WebP`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(WebpSpecification),
+            specification = FormatSpecification(Specification.Webp),
             mediaType = MediaType.WEBP,
             fileExtension = FileExtension("webp")
         )
@@ -715,7 +688,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff WebPub`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(ZipSpecification, RpfSpecification),
+            specification = FormatSpecification(Specification.Zip, Specification.Rpf),
             mediaType = MediaType.READIUM_WEBPUB,
             fileExtension = FileExtension("webpub")
         )
@@ -738,9 +711,9 @@ class AssetSnifferTest {
     fun `Sniff LCP protected Readium package`() = runBlocking {
         val format = Format(
             specification = FormatSpecification(
-                ZipSpecification,
-                RpfSpecification,
-                LcpSpecification
+                Specification.Zip,
+                Specification.Rpf,
+                Specification.Lcp
             ),
             mediaType = MediaType.READIUM_WEBPUB,
             fileExtension = FileExtension("webpub")
@@ -755,7 +728,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff WebPub manifest`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(JsonSpecification, RwpmSpecification),
+            specification = FormatSpecification(Specification.Json, Specification.Rwpm),
             mediaType = MediaType.READIUM_WEBPUB_MANIFEST,
             fileExtension = FileExtension("json")
         )
@@ -773,7 +746,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff W3C WPUB manifest`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(JsonSpecification, W3cPubManifestSpecification),
+            specification = FormatSpecification(Specification.Json, Specification.W3cPubManifest),
             mediaType = MediaType.W3C_WPUB_MANIFEST,
             fileExtension = FileExtension("json")
         )
@@ -787,7 +760,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff ZAB`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(ZipSpecification, InformalAudiobookSpecification),
+            specification = FormatSpecification(Specification.Zip, Specification.InformalAudiobook),
             mediaType = MediaType.ZAB,
             fileExtension = FileExtension("zab")
         )
@@ -805,7 +778,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff JSON`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(JsonSpecification),
+            specification = FormatSpecification(Specification.Json),
             mediaType = MediaType.JSON,
             fileExtension = FileExtension("json")
         )
@@ -819,7 +792,7 @@ class AssetSnifferTest {
     @Test
     fun `sniff JSON problem details`() = runBlocking {
         val format = Format(
-            specification = FormatSpecification(JsonSpecification, ProblemDetailsSpecification),
+            specification = FormatSpecification(Specification.Json, Specification.ProblemDetails),
             mediaType = MediaType.JSON_PROBLEM_DETAILS,
             fileExtension = FileExtension("json")
         )
@@ -844,7 +817,7 @@ class AssetSnifferTest {
     }
 
     private val cssFormat = Format(
-        specification = FormatSpecification(CssSpecification),
+        specification = FormatSpecification(Specification.Css),
         mediaType = MediaType.CSS,
         fileExtension = FileExtension("css")
     )
@@ -862,7 +835,7 @@ class AssetSnifferTest {
     }
 
     private val jsFormat = Format(
-        specification = FormatSpecification(JavaScriptSpecification),
+        specification = FormatSpecification(Specification.JavaScript),
         mediaType = MediaType.JAVASCRIPT,
         fileExtension = FileExtension("js")
     )
diff --git a/readium/shared/src/test/java/org/readium/r2/shared/util/format/DefaultSniffersTest.kt b/readium/shared/src/test/java/org/readium/r2/shared/util/format/DefaultSniffersTest.kt
index 311f969596..b771a174df 100644
--- a/readium/shared/src/test/java/org/readium/r2/shared/util/format/DefaultSniffersTest.kt
+++ b/readium/shared/src/test/java/org/readium/r2/shared/util/format/DefaultSniffersTest.kt
@@ -20,7 +20,7 @@ import org.robolectric.RobolectricTestRunner
 class DefaultSniffersTest {
 
     private val epubFormat = Format(
-        specification = FormatSpecification(ZipSpecification, EpubSpecification),
+        specification = FormatSpecification(Specification.Zip, Specification.Epub),
         mediaType = MediaType.EPUB,
         fileExtension = FileExtension("epub")
     )
@@ -41,7 +41,7 @@ class DefaultSniffersTest {
     @Test
     fun `Sniff Adobe ADEPT`() = runBlocking {
         assertEquals(
-            epubFormat.copy(specification = epubFormat.specification + AdeptSpecification),
+            epubFormat.copy(specification = epubFormat.specification + Specification.Adept),
             EpubDrmSniffer.sniffContainer(
                 format = epubFormat,
                 container = TestContainer(
@@ -64,7 +64,7 @@ class DefaultSniffersTest {
     @Test
     fun `Sniff Adobe ADEPT from rights xml`() = runBlocking {
         assertEquals(
-            epubFormat.copy(specification = epubFormat.specification + AdeptSpecification),
+            epubFormat.copy(specification = epubFormat.specification + Specification.Adept),
             EpubDrmSniffer.sniffContainer(
                 format = epubFormat,
                 container = TestContainer(
@@ -78,7 +78,7 @@ class DefaultSniffersTest {
     @Test
     fun `Sniff LCP protected EPUB`() = runBlocking {
         assertEquals(
-            epubFormat.copy(specification = epubFormat.specification + LcpSpecification),
+            epubFormat.copy(specification = epubFormat.specification + Specification.Lcp),
             EpubDrmSniffer.sniffContainer(
                 format = epubFormat,
                 container = TestContainer(Url("META-INF/license.lcpl")!! to "{}")
@@ -89,7 +89,7 @@ class DefaultSniffersTest {
     @Test
     fun `Sniff LCP protected EPUB missing the license`() = runBlocking {
         assertEquals(
-            epubFormat.copy(specification = epubFormat.specification + LcpSpecification),
+            epubFormat.copy(specification = epubFormat.specification + Specification.Lcp),
             EpubDrmSniffer.sniffContainer(
                 format = epubFormat,
                 container = TestContainer(
diff --git a/readium/shared/src/test/java/org/readium/r2/shared/util/resource/ZipContainerTest.kt b/readium/shared/src/test/java/org/readium/r2/shared/util/resource/ZipContainerTest.kt
index 6f92ea2b71..eacfee67c5 100644
--- a/readium/shared/src/test/java/org/readium/r2/shared/util/resource/ZipContainerTest.kt
+++ b/readium/shared/src/test/java/org/readium/r2/shared/util/resource/ZipContainerTest.kt
@@ -23,10 +23,9 @@ import org.readium.r2.shared.util.Url
 import org.readium.r2.shared.util.checkSuccess
 import org.readium.r2.shared.util.data.Container
 import org.readium.r2.shared.util.file.DirectoryContainer
-import org.readium.r2.shared.util.format.EpubSpecification
 import org.readium.r2.shared.util.format.Format
 import org.readium.r2.shared.util.format.FormatSpecification
-import org.readium.r2.shared.util.format.ZipSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.mediatype.MediaType
 import org.readium.r2.shared.util.use
 import org.readium.r2.shared.util.zip.FileZipArchiveProvider
@@ -44,7 +43,7 @@ class ZipContainerTest(val sut: suspend () -> Container<Resource>) {
             val epubZip = ZipContainerTest::class.java.getResource("epub.epub")
             assertNotNull(epubZip)
             val format = Format(
-                specification = FormatSpecification(ZipSpecification, EpubSpecification),
+                specification = FormatSpecification(Specification.Zip, Specification.Epub),
                 mediaType = MediaType.EPUB,
                 fileExtension = FileExtension("epub")
             )
diff --git a/readium/streamer/src/main/java/org/readium/r2/streamer/parser/audio/AudioParser.kt b/readium/streamer/src/main/java/org/readium/r2/streamer/parser/audio/AudioParser.kt
index d8563479b6..59d16e642a 100644
--- a/readium/streamer/src/main/java/org/readium/r2/streamer/parser/audio/AudioParser.kt
+++ b/readium/streamer/src/main/java/org/readium/r2/streamer/parser/audio/AudioParser.kt
@@ -20,18 +20,8 @@ import org.readium.r2.shared.util.asset.ContainerAsset
 import org.readium.r2.shared.util.asset.ResourceAsset
 import org.readium.r2.shared.util.data.Container
 import org.readium.r2.shared.util.data.ReadError
-import org.readium.r2.shared.util.format.AacSpecification
-import org.readium.r2.shared.util.format.AiffSpecification
-import org.readium.r2.shared.util.format.FlacSpecification
 import org.readium.r2.shared.util.format.Format
-import org.readium.r2.shared.util.format.InformalAudiobookSpecification
-import org.readium.r2.shared.util.format.Mp3Specification
-import org.readium.r2.shared.util.format.Mp4Specification
-import org.readium.r2.shared.util.format.OggSpecification
-import org.readium.r2.shared.util.format.OpusSpecification
 import org.readium.r2.shared.util.format.Specification
-import org.readium.r2.shared.util.format.WavSpecification
-import org.readium.r2.shared.util.format.WebmSpecification
 import org.readium.r2.shared.util.getOrElse
 import org.readium.r2.shared.util.logging.WarningLogger
 import org.readium.r2.shared.util.resource.Resource
@@ -79,7 +69,7 @@ public class AudioParser(
     private suspend fun parseContainerAsset(
         asset: ContainerAsset
     ): Try<Publication.Builder, PublicationParser.ParseError> {
-        if (!asset.format.conformsTo(InformalAudiobookSpecification)) {
+        if (!asset.format.conformsTo(Specification.InformalAudiobook)) {
             return Try.failure(PublicationParser.ParseError.FormatNotSupported())
         }
 
@@ -141,14 +131,14 @@ public class AudioParser(
 
     private val audioSpecifications: Set<Specification> =
         setOf(
-            AacSpecification,
-            AiffSpecification,
-            FlacSpecification,
-            Mp4Specification,
-            Mp3Specification,
-            OggSpecification,
-            OpusSpecification,
-            WavSpecification,
-            WebmSpecification
+            Specification.Aac,
+            Specification.Aiff,
+            Specification.Flac,
+            Specification.Mp4,
+            Specification.Mp3,
+            Specification.Ogg,
+            Specification.Opus,
+            Specification.Wav,
+            Specification.Webm
         )
 }
diff --git a/readium/streamer/src/main/java/org/readium/r2/streamer/parser/epub/EpubParser.kt b/readium/streamer/src/main/java/org/readium/r2/streamer/parser/epub/EpubParser.kt
index 3129dd9617..7dcd219a8c 100644
--- a/readium/streamer/src/main/java/org/readium/r2/streamer/parser/epub/EpubParser.kt
+++ b/readium/streamer/src/main/java/org/readium/r2/streamer/parser/epub/EpubParser.kt
@@ -26,7 +26,7 @@ import org.readium.r2.shared.util.data.Readable
 import org.readium.r2.shared.util.data.decodeXml
 import org.readium.r2.shared.util.data.readDecodeOrElse
 import org.readium.r2.shared.util.data.readDecodeOrNull
-import org.readium.r2.shared.util.format.EpubSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.fromEpubHref
 import org.readium.r2.shared.util.getOrElse
 import org.readium.r2.shared.util.logging.WarningLogger
@@ -52,7 +52,7 @@ public class EpubParser(
         asset: Asset,
         warnings: WarningLogger?
     ): Try<Publication.Builder, PublicationParser.ParseError> {
-        if (asset !is ContainerAsset || !asset.format.conformsTo(EpubSpecification)) {
+        if (asset !is ContainerAsset || !asset.format.conformsTo(Specification.Epub)) {
             return Try.failure(PublicationParser.ParseError.FormatNotSupported())
         }
 
diff --git a/readium/streamer/src/main/java/org/readium/r2/streamer/parser/image/ImageParser.kt b/readium/streamer/src/main/java/org/readium/r2/streamer/parser/image/ImageParser.kt
index 9a31fcc2b7..a65efef755 100644
--- a/readium/streamer/src/main/java/org/readium/r2/streamer/parser/image/ImageParser.kt
+++ b/readium/streamer/src/main/java/org/readium/r2/streamer/parser/image/ImageParser.kt
@@ -21,17 +21,8 @@ import org.readium.r2.shared.util.asset.ContainerAsset
 import org.readium.r2.shared.util.asset.ResourceAsset
 import org.readium.r2.shared.util.data.Container
 import org.readium.r2.shared.util.data.ReadError
-import org.readium.r2.shared.util.format.AvifSpecification
-import org.readium.r2.shared.util.format.BmpSpecification
 import org.readium.r2.shared.util.format.Format
-import org.readium.r2.shared.util.format.GifSpecification
-import org.readium.r2.shared.util.format.InformalComicSpecification
-import org.readium.r2.shared.util.format.JpegSpecification
-import org.readium.r2.shared.util.format.JxlSpecification
-import org.readium.r2.shared.util.format.PngSpecification
 import org.readium.r2.shared.util.format.Specification
-import org.readium.r2.shared.util.format.TiffSpecification
-import org.readium.r2.shared.util.format.WebpSpecification
 import org.readium.r2.shared.util.getOrElse
 import org.readium.r2.shared.util.logging.WarningLogger
 import org.readium.r2.shared.util.mediatype.MediaType
@@ -80,7 +71,7 @@ public class ImageParser(
     private suspend fun parseContainerAsset(
         asset: ContainerAsset
     ): Try<Publication.Builder, PublicationParser.ParseError> {
-        if (!asset.format.conformsTo(InformalComicSpecification)) {
+        if (!asset.format.conformsTo(Specification.InformalComic)) {
             return Try.failure(PublicationParser.ParseError.FormatNotSupported())
         }
 
@@ -147,13 +138,13 @@ public class ImageParser(
 
     private val bitmapSpecifications: Set<Specification> =
         setOf(
-            AvifSpecification,
-            BmpSpecification,
-            GifSpecification,
-            JpegSpecification,
-            JxlSpecification,
-            PngSpecification,
-            TiffSpecification,
-            WebpSpecification
+            Specification.Avif,
+            Specification.Bmp,
+            Specification.Gif,
+            Specification.Jpeg,
+            Specification.Jxl,
+            Specification.Png,
+            Specification.Tiff,
+            Specification.Webp
         )
 }
diff --git a/readium/streamer/src/main/java/org/readium/r2/streamer/parser/pdf/PdfParser.kt b/readium/streamer/src/main/java/org/readium/r2/streamer/parser/pdf/PdfParser.kt
index 1a4382dc2c..f9d8910964 100644
--- a/readium/streamer/src/main/java/org/readium/r2/streamer/parser/pdf/PdfParser.kt
+++ b/readium/streamer/src/main/java/org/readium/r2/streamer/parser/pdf/PdfParser.kt
@@ -14,7 +14,7 @@ import org.readium.r2.shared.publication.services.InMemoryCoverService
 import org.readium.r2.shared.util.Try
 import org.readium.r2.shared.util.asset.Asset
 import org.readium.r2.shared.util.asset.ResourceAsset
-import org.readium.r2.shared.util.format.PdfSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.getOrElse
 import org.readium.r2.shared.util.logging.WarningLogger
 import org.readium.r2.shared.util.mediatype.MediaType
@@ -38,7 +38,7 @@ public class PdfParser(
         asset: Asset,
         warnings: WarningLogger?
     ): Try<Publication.Builder, PublicationParser.ParseError> {
-        if (asset !is ResourceAsset || !asset.format.conformsTo(PdfSpecification)) {
+        if (asset !is ResourceAsset || !asset.format.conformsTo(Specification.Pdf)) {
             return Try.failure(PublicationParser.ParseError.FormatNotSupported())
         }
 
diff --git a/readium/streamer/src/main/java/org/readium/r2/streamer/parser/readium/ReadiumWebPubParser.kt b/readium/streamer/src/main/java/org/readium/r2/streamer/parser/readium/ReadiumWebPubParser.kt
index eb2c7d1541..809593f2a6 100644
--- a/readium/streamer/src/main/java/org/readium/r2/streamer/parser/readium/ReadiumWebPubParser.kt
+++ b/readium/streamer/src/main/java/org/readium/r2/streamer/parser/readium/ReadiumWebPubParser.kt
@@ -7,6 +7,7 @@
 package org.readium.r2.streamer.parser.readium
 
 import android.content.Context
+import org.readium.r2.shared.publication.Manifest
 import org.readium.r2.shared.publication.Publication
 import org.readium.r2.shared.publication.services.InMemoryCacheService
 import org.readium.r2.shared.publication.services.PerResourcePositionsService
@@ -27,9 +28,7 @@ import org.readium.r2.shared.util.data.ReadError
 import org.readium.r2.shared.util.data.decodeRwpm
 import org.readium.r2.shared.util.data.readDecodeOrElse
 import org.readium.r2.shared.util.format.FormatSpecification
-import org.readium.r2.shared.util.format.LcpSpecification
-import org.readium.r2.shared.util.format.RpfSpecification
-import org.readium.r2.shared.util.format.RwpmSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.http.HttpClient
 import org.readium.r2.shared.util.http.HttpContainer
 import org.readium.r2.shared.util.logging.WarningLogger
@@ -62,7 +61,7 @@ public class ReadiumWebPubParser(
         container: Container<Resource>,
         formatSpecification: FormatSpecification
     ): Try<Publication.Builder, PublicationParser.ParseError> {
-        if (!formatSpecification.conformsTo(RpfSpecification)) {
+        if (!formatSpecification.conformsTo(Specification.Rpf)) {
             return Try.failure(PublicationParser.ParseError.FormatNotSupported())
         }
 
@@ -81,27 +80,15 @@ public class ReadiumWebPubParser(
                 recover = { return Try.failure(PublicationParser.ParseError.Reading(it)) }
             )
 
-        // Checks the requirements from the LCPDF specification.
-        // https://readium.org/lcp-specs/notes/lcp-for-pdf.html
-        val readingOrder = manifest.readingOrder
-        if (manifest.conformsTo(Publication.Profile.PDF) && formatSpecification.conformsTo(
-                LcpSpecification
-            ) &&
-            (readingOrder.isEmpty() || !readingOrder.all { MediaType.PDF.matches(it.mediaType) })
-        ) {
-            return Try.failure(
-                PublicationParser.ParseError.Reading(
-                    ReadError.Decoding("Invalid LCP Protected PDF.")
-                )
-            )
-        }
+        checkProfileRequirements(manifest)
+            ?.let { return Try.failure(it) }
 
         val servicesBuilder = Publication.ServicesBuilder().apply {
             cacheServiceFactory = InMemoryCacheService.createFactory(context)
 
             positionsServiceFactory = when {
                 manifest.conformsTo(Publication.Profile.PDF) && formatSpecification.conformsTo(
-                    LcpSpecification
+                    Specification.Lcp
                 ) ->
                     pdfFactory?.let { LcpdfPositionsService.create(it) }
                 manifest.conformsTo(Publication.Profile.DIVINA) ->
@@ -122,11 +109,42 @@ public class ReadiumWebPubParser(
         return Try.success(publicationBuilder)
     }
 
+    private fun checkProfileRequirements(manifest: Manifest): PublicationParser.ParseError? =
+        when {
+            manifest.conformsTo(Publication.Profile.PDF) -> {
+                if (manifest.readingOrder.isEmpty() ||
+                    manifest.readingOrder.any { !MediaType.PDF.matches(it.mediaType) }
+                ) {
+                    PublicationParser.ParseError.Reading(
+                        ReadError.Decoding(
+                            "Publication does not conform to the PDF profile specification."
+                        )
+                    )
+                } else {
+                    null
+                }
+            }
+            manifest.conformsTo(Publication.Profile.AUDIOBOOK) -> {
+                if (manifest.readingOrder.isEmpty()) {
+                    PublicationParser.ParseError.Reading(
+                        ReadError.Decoding(
+                            "Publication does not conform to the Audiobook profile specification."
+                        )
+                    )
+                } else {
+                    null
+                }
+            }
+            else -> {
+                null
+            }
+        }
+
     private suspend fun parseResourceAsset(
         resource: Resource,
         formatSpecification: FormatSpecification
     ): Try<Publication.Builder, PublicationParser.ParseError> {
-        if (!formatSpecification.conformsTo(RwpmSpecification)) {
+        if (!formatSpecification.conformsTo(Specification.Rwpm)) {
             return Try.failure(PublicationParser.ParseError.FormatNotSupported())
         }
 
@@ -169,6 +187,6 @@ public class ReadiumWebPubParser(
                 HttpContainer(baseUrl, resources, httpClient)
             )
 
-        return parseContainerAsset(container, FormatSpecification(RpfSpecification))
+        return parseContainerAsset(container, FormatSpecification(Specification.Rpf))
     }
 }
diff --git a/readium/streamer/src/test/java/org/readium/r2/streamer/parser/image/ImageParserTest.kt b/readium/streamer/src/test/java/org/readium/r2/streamer/parser/image/ImageParserTest.kt
index 6fee0b8388..74419c5fd5 100644
--- a/readium/streamer/src/test/java/org/readium/r2/streamer/parser/image/ImageParserTest.kt
+++ b/readium/streamer/src/test/java/org/readium/r2/streamer/parser/image/ImageParserTest.kt
@@ -27,9 +27,7 @@ import org.readium.r2.shared.util.checkSuccess
 import org.readium.r2.shared.util.file.FileResource
 import org.readium.r2.shared.util.format.Format
 import org.readium.r2.shared.util.format.FormatSpecification
-import org.readium.r2.shared.util.format.InformalComicSpecification
-import org.readium.r2.shared.util.format.JpegSpecification
-import org.readium.r2.shared.util.format.ZipSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.http.DefaultHttpClient
 import org.readium.r2.shared.util.mediatype.MediaType
 import org.readium.r2.shared.util.zip.ZipArchiveOpener
@@ -52,7 +50,7 @@ class ImageParserTest {
         val file = fileForResource("futuristic_tales.cbz")
         val resource = FileResource(file)
         val format = Format(
-            specification = FormatSpecification(ZipSpecification, InformalComicSpecification),
+            specification = FormatSpecification(Specification.Zip, Specification.InformalComic),
             mediaType = MediaType.CBZ,
             fileExtension = FileExtension("cbz")
         )
@@ -64,7 +62,7 @@ class ImageParserTest {
         val file = fileForResource("futuristic_tales.jpg")
         val resource = FileResource(file)
         val format = Format(
-            specification = FormatSpecification(JpegSpecification),
+            specification = FormatSpecification(Specification.Jpeg),
             mediaType = MediaType.JPEG,
             fileExtension = FileExtension("jpg")
         )
diff --git a/test-app/src/main/java/org/readium/r2/testapp/domain/PublicationRetriever.kt b/test-app/src/main/java/org/readium/r2/testapp/domain/PublicationRetriever.kt
index a0b2124f5c..f92f973db4 100644
--- a/test-app/src/main/java/org/readium/r2/testapp/domain/PublicationRetriever.kt
+++ b/test-app/src/main/java/org/readium/r2/testapp/domain/PublicationRetriever.kt
@@ -22,7 +22,7 @@ import org.readium.r2.shared.util.data.ReadError
 import org.readium.r2.shared.util.file.FileSystemError
 import org.readium.r2.shared.util.format.Format
 import org.readium.r2.shared.util.format.FormatHints
-import org.readium.r2.shared.util.format.LcpLicenseSpecification
+import org.readium.r2.shared.util.format.Specification
 import org.readium.r2.shared.util.getOrElse
 import org.readium.r2.shared.util.http.HttpClient
 import org.readium.r2.shared.util.http.HttpRequest
@@ -196,7 +196,7 @@ private class LocalPublicationRetriever(
 
         if (
             sourceAsset is ResourceAsset &&
-            sourceAsset.format.conformsTo(LcpLicenseSpecification)
+            sourceAsset.format.conformsTo(Specification.LcpLicense)
         ) {
             return if (lcpService == null) {
                 sourceAsset.close()