diff --git a/readium/navigators/media/common/src/main/java/org/readium/navigator/media/common/DefaultMediaMetadataFactory.kt b/readium/navigators/media/common/src/main/java/org/readium/navigator/media/common/DefaultMediaMetadataFactory.kt
index 6f73642bd6..2a09b9445a 100644
--- a/readium/navigators/media/common/src/main/java/org/readium/navigator/media/common/DefaultMediaMetadataFactory.kt
+++ b/readium/navigators/media/common/src/main/java/org/readium/navigator/media/common/DefaultMediaMetadataFactory.kt
@@ -45,7 +45,7 @@ internal class DefaultMediaMetadataFactory(
             // byte array will go cross processes and should be kept small
             publication.coverFitting(Size(400, 400))
                 ?.compress(Bitmap.CompressFormat.PNG, 80, byteStream)
-            byteStream.toByteArray()
+                ?.let { byteStream.toByteArray() }
         }
     }
 
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 43ea18cbe7..9e780c5fd4 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
@@ -18,7 +18,7 @@ import org.readium.r2.shared.util.format.AdeptSpecification
 import org.readium.r2.shared.util.format.LcpSpecification
 
 /**
- * [ContentProtection] implementation used as a fallback by when detecting known DRMs
+ * [ContentProtection] implementation used as a fallback when detecting known DRMs
  * not supported by the app.
  */
 public class FallbackContentProtection : ContentProtection {
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 1ccb4cadbc..d8563479b6 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
@@ -63,7 +63,7 @@ public class AudioParser(
     private fun parseResourceAsset(
         asset: ResourceAsset
     ): Try<Publication.Builder, PublicationParser.ParseError> {
-        if (asset.format.conformsToAny(audioSpecifications)) {
+        if (!asset.format.conformsToAny(audioSpecifications)) {
             return Try.failure(PublicationParser.ParseError.FormatNotSupported())
         }