diff --git a/app/src/main/java/org/oxycblt/auxio/music/RevisionedLibrary.kt b/app/src/main/java/org/oxycblt/auxio/music/RevisionedLibrary.kt
index 0c425959e..df69debad 100644
--- a/app/src/main/java/org/oxycblt/auxio/music/RevisionedLibrary.kt
+++ b/app/src/main/java/org/oxycblt/auxio/music/RevisionedLibrary.kt
@@ -23,12 +23,13 @@ import androidx.media3.common.util.Log
 import java.util.UUID
 import org.oxycblt.auxio.util.unlikelyToBeNull
 import org.oxycblt.musikr.cover.Cover
+import org.oxycblt.musikr.cover.CoverFormat
 import org.oxycblt.musikr.cover.MutableStoredCovers
 import org.oxycblt.musikr.cover.StoredCovers
 
 open class RevisionedStoredCovers(private val context: Context, private val revision: UUID?) :
     StoredCovers {
-    protected val inner = revision?.let { StoredCovers.at(context, "covers_$it") }
+    protected val inner = revision?.let { StoredCovers.from(context, "covers_$it", CoverFormat.jpeg()) }
 
     override suspend fun obtain(id: String): RevisionedCover? {
         val split = id.split('@', limit = 2)
@@ -43,7 +44,7 @@ open class RevisionedStoredCovers(private val context: Context, private val revi
             val storedCovers = unlikelyToBeNull(inner)
             return storedCovers.obtain(coverId)?.let { RevisionedCover(revision, it) }
         } else {
-            val storedCovers = StoredCovers.at(context, "covers_$coverRevision")
+            val storedCovers = StoredCovers.from(context, "covers_$coverRevision", CoverFormat.jpeg())
             return storedCovers.obtain(coverId)?.let { RevisionedCover(coverRevision, it) }
         }
     }
diff --git a/musikr/src/main/java/org/oxycblt/musikr/cache/Cache.kt b/musikr/src/main/java/org/oxycblt/musikr/cache/Cache.kt
index 81de567d9..5b43f8d8c 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/cache/Cache.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/cache/Cache.kt
@@ -22,10 +22,10 @@ import org.oxycblt.musikr.cover.StoredCovers
 import org.oxycblt.musikr.fs.DeviceFile
 import org.oxycblt.musikr.pipeline.RawSong
 
-interface Cache {
-    suspend fun read(file: DeviceFile, storedCovers: StoredCovers): CacheResult
+abstract class Cache {
+    internal abstract suspend fun read(file: DeviceFile, storedCovers: StoredCovers): CacheResult
 
-    suspend fun write(song: RawSong)
+    internal abstract suspend fun write(song: RawSong)
 
     companion object {
         fun full(db: CacheDatabase): Cache = FullCache(db.cachedSongsDao())
@@ -34,13 +34,13 @@ interface Cache {
     }
 }
 
-sealed interface CacheResult {
+internal sealed interface CacheResult {
     data class Hit(val song: RawSong) : CacheResult
 
     data class Miss(val file: DeviceFile) : CacheResult
 }
 
-private class FullCache(private val cacheInfoDao: CacheInfoDao) : Cache {
+private class FullCache(private val cacheInfoDao: CacheInfoDao) : Cache() {
     override suspend fun read(file: DeviceFile, storedCovers: StoredCovers) =
         cacheInfoDao.selectSong(file.uri.toString(), file.lastModified)?.let {
             CacheResult.Hit(it.intoRawSong(file, storedCovers))
@@ -50,7 +50,7 @@ private class FullCache(private val cacheInfoDao: CacheInfoDao) : Cache {
         cacheInfoDao.updateSong(CachedSong.fromRawSong(song))
 }
 
-private class WriteOnlyCache(private val cacheInfoDao: CacheInfoDao) : Cache {
+private class WriteOnlyCache(private val cacheInfoDao: CacheInfoDao) : Cache() {
     override suspend fun read(file: DeviceFile, storedCovers: StoredCovers) = CacheResult.Miss(file)
 
     override suspend fun write(song: RawSong) =
diff --git a/musikr/src/main/java/org/oxycblt/musikr/cover/CoverFiles.kt b/musikr/src/main/java/org/oxycblt/musikr/cover/CoverFiles.kt
index 73982e4ad..86aaf51ef 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/cover/CoverFiles.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/cover/CoverFiles.kt
@@ -27,18 +27,18 @@ import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
 import kotlinx.coroutines.withContext
 
-interface CoverFiles {
+internal interface CoverFiles {
     suspend fun find(id: String): CoverFile?
 
     suspend fun write(id: String, data: ByteArray): CoverFile?
 
     companion object {
-        fun at(context: Context, path: String): CoverFiles =
-            CoverFilesImpl(File(context.filesDir, path).also { it.mkdirs() }, CoverFormat.jpeg())
+        fun at(context: Context, path: String, format: CoverFormat): CoverFiles =
+            CoverFilesImpl(File(context.filesDir, path).also { it.mkdirs() }, format)
     }
 }
 
-interface CoverFile {
+internal interface CoverFile {
     suspend fun open(): InputStream?
 }
 
diff --git a/musikr/src/main/java/org/oxycblt/musikr/cover/CoverFormat.kt b/musikr/src/main/java/org/oxycblt/musikr/cover/CoverFormat.kt
index c7b23967b..d6f5aca08 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/cover/CoverFormat.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/cover/CoverFormat.kt
@@ -22,10 +22,10 @@ import android.graphics.Bitmap
 import android.graphics.BitmapFactory
 import java.io.OutputStream
 
-internal interface CoverFormat {
-    val extension: String
+abstract class CoverFormat {
+    internal abstract val extension: String
 
-    fun transcodeInto(data: ByteArray, output: OutputStream): Boolean
+    internal abstract fun transcodeInto(data: ByteArray, output: OutputStream): Boolean
 
     companion object {
         // Enable if perhaps you want to try other formats.
@@ -50,7 +50,7 @@ private class CoverFormatImpl(
     val size: Int,
     val quality: Int,
     val format: Bitmap.CompressFormat,
-) : CoverFormat {
+) : CoverFormat() {
     override fun transcodeInto(data: ByteArray, output: OutputStream) =
         BitmapFactory.Options().run {
             inJustDecodeBounds = true
diff --git a/musikr/src/main/java/org/oxycblt/musikr/cover/StoredCovers.kt b/musikr/src/main/java/org/oxycblt/musikr/cover/StoredCovers.kt
index fb5140e2f..c3d1a3395 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/cover/StoredCovers.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/cover/StoredCovers.kt
@@ -24,8 +24,8 @@ interface StoredCovers {
     suspend fun obtain(id: String): Cover.Single?
 
     companion object {
-        fun at(context: Context, path: String): MutableStoredCovers =
-            FileStoredCovers(CoverIdentifier.md5(), CoverFiles.at(context, path))
+        fun from(context: Context, path: String, format: CoverFormat): MutableStoredCovers =
+            FileStoredCovers(CoverIdentifier.md5(), CoverFiles.at(context, path, format))
     }
 }
 
diff --git a/musikr/src/main/java/org/oxycblt/musikr/fs/DeviceFile.kt b/musikr/src/main/java/org/oxycblt/musikr/fs/DeviceFile.kt
index 4d6b39ca5..98025a75a 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/fs/DeviceFile.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/fs/DeviceFile.kt
@@ -20,7 +20,7 @@ package org.oxycblt.musikr.fs
 
 import android.net.Uri
 
-data class DeviceFile(
+internal data class DeviceFile(
     val uri: Uri,
     val mimeType: String,
     val path: Path,
diff --git a/musikr/src/main/java/org/oxycblt/musikr/metadata/Metadata.kt b/musikr/src/main/java/org/oxycblt/musikr/metadata/Metadata.kt
index f73745c95..758e4483a 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/metadata/Metadata.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/metadata/Metadata.kt
@@ -53,7 +53,7 @@ internal data class Metadata(
     }
 }
 
-data class Properties(
+internal data class Properties(
     val mimeType: String,
     val durationMs: Long,
     val bitrateKbps: Int,
diff --git a/musikr/src/main/java/org/oxycblt/musikr/pipeline/ExtractStep.kt b/musikr/src/main/java/org/oxycblt/musikr/pipeline/ExtractStep.kt
index ca220546c..10d2c4468 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/pipeline/ExtractStep.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/pipeline/ExtractStep.kt
@@ -159,7 +159,7 @@ private class ExtractStepImpl(
     private data class FileWith<T>(val file: DeviceFile, val with: T)
 }
 
-data class RawSong(
+internal data class RawSong(
     val file: DeviceFile,
     val properties: Properties,
     val tags: ParsedTags,
diff --git a/musikr/src/main/java/org/oxycblt/musikr/playlist/PlaylistFile.kt b/musikr/src/main/java/org/oxycblt/musikr/playlist/PlaylistFile.kt
index 231705cb7..ad52037d6 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/playlist/PlaylistFile.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/playlist/PlaylistFile.kt
@@ -21,18 +21,18 @@ package org.oxycblt.musikr.playlist
 import org.oxycblt.musikr.Music
 import org.oxycblt.musikr.Song
 
-data class PlaylistFile(
+internal data class PlaylistFile(
     val name: String,
     val songPointers: List<SongPointer>,
     val handle: PlaylistHandle
 )
 
-sealed interface SongPointer {
+internal sealed interface SongPointer {
     data class UID(val uid: Music.UID) : SongPointer
     //    data class Path(val options: List<Path>) : SongPointer
 }
 
-interface PlaylistHandle {
+internal interface PlaylistHandle {
     val uid: Music.UID
 
     suspend fun rename(name: String)
diff --git a/musikr/src/main/java/org/oxycblt/musikr/playlist/db/StoredPlaylists.kt b/musikr/src/main/java/org/oxycblt/musikr/playlist/db/StoredPlaylists.kt
index e33e23dc8..9095bbe43 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/playlist/db/StoredPlaylists.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/playlist/db/StoredPlaylists.kt
@@ -24,10 +24,10 @@ import org.oxycblt.musikr.playlist.PlaylistFile
 import org.oxycblt.musikr.playlist.PlaylistHandle
 import org.oxycblt.musikr.playlist.SongPointer
 
-interface StoredPlaylists {
-    suspend fun new(name: String, songs: List<Song>): PlaylistHandle
+abstract class StoredPlaylists {
+    internal abstract suspend fun new(name: String, songs: List<Song>): PlaylistHandle
 
-    suspend fun read(): List<PlaylistFile>
+    internal abstract suspend fun read(): List<PlaylistFile>
 
     companion object {
         fun from(database: PlaylistDatabase): StoredPlaylists =
@@ -35,7 +35,7 @@ interface StoredPlaylists {
     }
 }
 
-private class StoredPlaylistsImpl(private val playlistDao: PlaylistDao) : StoredPlaylists {
+private class StoredPlaylistsImpl(private val playlistDao: PlaylistDao) : StoredPlaylists() {
     override suspend fun new(name: String, songs: List<Song>): PlaylistHandle {
         val info = PlaylistInfo(Music.UID.auxio(Music.UID.Item.PLAYLIST), name)
         playlistDao.insertPlaylist(RawPlaylist(info, songs.map { PlaylistSong(it.uid) }))
diff --git a/musikr/src/main/java/org/oxycblt/musikr/playlist/m3u/M3U.kt b/musikr/src/main/java/org/oxycblt/musikr/playlist/m3u/M3U.kt
index 448ea8b4f..be4bee901 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/playlist/m3u/M3U.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/playlist/m3u/M3U.kt
@@ -41,7 +41,7 @@ import org.oxycblt.musikr.util.unlikelyToBeNull
  *
  * @author Alexander Capehart (OxygenCobalt)
  */
-interface M3U {
+abstract class M3U {
     /**
      * Reads an M3U file from the given [stream] and returns a [ImportedPlaylist] containing the
      * paths to the files listed in the M3U file.
@@ -51,7 +51,7 @@ interface M3U {
      *   resolve relative paths.
      * @return An [ImportedPlaylist] containing the paths to the files listed in the M3U file,
      */
-    fun read(stream: InputStream, workingDirectory: Path): ImportedPlaylist?
+    internal abstract fun read(stream: InputStream, workingDirectory: Path): ImportedPlaylist?
 
     /**
      * Writes the given [playlist] to the given [outputStream] in the M3U format,.
@@ -62,7 +62,7 @@ interface M3U {
      *   create relative paths to where the M3U file is assumed to be stored.
      * @param config The configuration to use when exporting the playlist.
      */
-    fun write(
+    internal abstract fun write(
         playlist: Playlist,
         outputStream: OutputStream,
         workingDirectory: Path,
@@ -73,11 +73,11 @@ interface M3U {
         /** The mime type used for M3U files by the android system. */
         const val MIME_TYPE = "audio/x-mpegurl"
 
-        fun from(context: Context): M3U = M3UImpl(VolumeManager.from(context))
+        internal fun from(context: Context): M3U = M3UImpl(VolumeManager.from(context))
     }
 }
 
-private class M3UImpl(private val volumeManager: VolumeManager) : M3U {
+private class M3UImpl(private val volumeManager: VolumeManager) : M3U() {
     override fun read(stream: InputStream, workingDirectory: Path): ImportedPlaylist? {
         val volumes = volumeManager.getVolumes()
         val reader = BufferedReader(InputStreamReader(stream))
diff --git a/musikr/src/main/java/org/oxycblt/musikr/tag/parse/ParsedTags.kt b/musikr/src/main/java/org/oxycblt/musikr/tag/parse/ParsedTags.kt
index 2a143aee7..a7dc4d3c5 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/tag/parse/ParsedTags.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/tag/parse/ParsedTags.kt
@@ -20,7 +20,7 @@ package org.oxycblt.musikr.tag.parse
 
 import org.oxycblt.musikr.tag.Date
 
-data class ParsedTags(
+internal data class ParsedTags(
     val durationMs: Long,
     val replayGainTrackAdjustment: Float? = null,
     val replayGainAlbumAdjustment: Float? = null,