music: refactor metadata extractor

Refactor the internal tag management portion of MetadataExtractor into a
new "Tags" object that can now be re-used in the ReplayGain system.

This also does a minor rework to the ReplayGain object to make it
totally self-sufficient.

CHANGELOG.md

@@ -10,6 +10,9 @@
 - Value lists are now properly localized
 - Queue no longer primarily shows previous songs when opened
 
+#### What's Changed
+- R128 Gain tags are now only used when playing OPUS files
+
 #### What's Fixed
 - Fixed mangled multi-value ID3v2 tags when UTF-16 is used
 

app/src/main/java/org/oxycblt/auxio/detail/Detail.kt

@@ -20,7 +20,7 @@ package org.oxycblt.auxio.detail
 import androidx.annotation.StringRes
 import org.oxycblt.auxio.list.Item
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.music.storage.MimeType
+import org.oxycblt.auxio.music.filesystem.MimeType
 
 /**
  * A header variation that displays a button to open a sort menu.

app/src/main/java/org/oxycblt/auxio/detail/DetailAppBarLayout.kt

@@ -36,8 +36,8 @@ import org.oxycblt.auxio.util.getInteger
 import org.oxycblt.auxio.util.lazyReflectedField
 
 /**
- * An [CoordinatorAppBarLayout] that displays the title of a hidden [Toolbar] when the scrolling view goes
+ * An [CoordinatorAppBarLayout] that displays the title of a hidden [Toolbar] when the scrolling
- * beyond it's first item.
+ * view goes beyond it's first item.
  *
  * This is intended for the detail views, in which the first item is the album/artist/genre header,
  * and thus scrolling past them should make the toolbar show the name in order to give context on

app/src/main/java/org/oxycblt/auxio/detail/DetailViewModel.kt

@@ -39,7 +39,7 @@ import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.music.Sort
-import org.oxycblt.auxio.music.storage.MimeType
+import org.oxycblt.auxio.music.filesystem.MimeType
 import org.oxycblt.auxio.settings.Settings
 import org.oxycblt.auxio.util.*
 

app/src/main/java/org/oxycblt/auxio/music/Music.kt

@@ -30,9 +30,9 @@ import kotlinx.parcelize.IgnoredOnParcel
 import kotlinx.parcelize.Parcelize
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.list.Item
+import org.oxycblt.auxio.music.filesystem.*
 import org.oxycblt.auxio.music.parsing.parseId3GenreNames
 import org.oxycblt.auxio.music.parsing.parseMultiValue
-import org.oxycblt.auxio.music.storage.*
 import org.oxycblt.auxio.settings.Settings
 import org.oxycblt.auxio.util.nonZeroOrNull
 import org.oxycblt.auxio.util.unlikelyToBeNull

app/src/main/java/org/oxycblt/auxio/music/MusicStore.kt

@@ -20,8 +20,8 @@ package org.oxycblt.auxio.music
 import android.content.Context
 import android.net.Uri
 import android.provider.OpenableColumns
-import org.oxycblt.auxio.music.storage.contentResolverSafe
+import org.oxycblt.auxio.music.filesystem.contentResolverSafe
-import org.oxycblt.auxio.music.storage.useQuery
+import org.oxycblt.auxio.music.filesystem.useQuery
 
 /**
  * A repository granting access to the music library..

app/src/main/java/org/oxycblt/auxio/music/extractor/ExtractionResult.kt

@@ -24,10 +24,8 @@ package org.oxycblt.auxio.music.extractor
 enum class ExtractionResult {
     /** A raw song was successfully extracted from the cache. */
     CACHED,
-
     /** A raw song was successfully extracted from parsing it's file. */
     PARSED,
-
     /** A raw song could not be parsed. */
     NONE
 }

app/src/main/java/org/oxycblt/auxio/music/extractor/MediaStoreExtractor.kt

@@ -26,17 +26,17 @@ import android.provider.MediaStore
 import androidx.annotation.RequiresApi
 import androidx.core.database.getIntOrNull
 import androidx.core.database.getStringOrNull
-import org.oxycblt.auxio.music.Date
 import java.io.File
+import org.oxycblt.auxio.music.Date
 import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.music.filesystem.Directory
+import org.oxycblt.auxio.music.filesystem.contentResolverSafe
+import org.oxycblt.auxio.music.filesystem.directoryCompat
+import org.oxycblt.auxio.music.filesystem.mediaStoreVolumeNameCompat
+import org.oxycblt.auxio.music.filesystem.safeQuery
+import org.oxycblt.auxio.music.filesystem.storageVolumesCompat
+import org.oxycblt.auxio.music.filesystem.useQuery
 import org.oxycblt.auxio.music.parsing.parseId3v2Position
-import org.oxycblt.auxio.music.storage.Directory
-import org.oxycblt.auxio.music.storage.contentResolverSafe
-import org.oxycblt.auxio.music.storage.directoryCompat
-import org.oxycblt.auxio.music.storage.mediaStoreVolumeNameCompat
-import org.oxycblt.auxio.music.storage.safeQuery
-import org.oxycblt.auxio.music.storage.storageVolumesCompat
-import org.oxycblt.auxio.music.storage.useQuery
 import org.oxycblt.auxio.settings.Settings
 import org.oxycblt.auxio.util.getSystemServiceCompat
 import org.oxycblt.auxio.util.logD

app/src/main/java/org/oxycblt/auxio/music/extractor/MetadataExtractor.kt

@@ -21,14 +21,10 @@ import android.content.Context
 import androidx.core.text.isDigitsOnly
 import com.google.android.exoplayer2.MediaItem
 import com.google.android.exoplayer2.MetadataRetriever
-import com.google.android.exoplayer2.metadata.Metadata
-import com.google.android.exoplayer2.metadata.id3.TextInformationFrame
-import com.google.android.exoplayer2.metadata.vorbis.VorbisComment
 import org.oxycblt.auxio.music.Date
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.music.parsing.correctWhitespace
+import org.oxycblt.auxio.music.filesystem.toAudioUri
 import org.oxycblt.auxio.music.parsing.parseId3v2Position
-import org.oxycblt.auxio.music.storage.toAudioUri
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.logW
 
@@ -164,7 +160,9 @@ class Task(context: Context, private val raw: Song.Raw) {
 
         val metadata = format.metadata
         if (metadata != null) {
-            populateWithMetadata(metadata)
+            val tags = Tags(metadata)
+            populateWithId3v2(tags.id3v2)
+            populateWithVorbis(tags.vorbis)
         } else {
             logD("No metadata could be extracted for ${raw.name}")
         }
@@ -172,51 +170,6 @@ class Task(context: Context, private val raw: Song.Raw) {
         return raw
     }
 
-    /**
-     * Complete this instance's [Song.Raw] with the newly extracted [Metadata].
-     * @param metadata The [Metadata] to complete the [Song.Raw] with.
-     */
-    private fun populateWithMetadata(metadata: Metadata) {
-        val id3v2Tags = mutableMapOf<String, List<String>>()
-        val vorbisTags = mutableMapOf<String, MutableList<String>>()
-
-        // ExoPlayer only exposes ID3v2 and Vorbis metadata, which constitutes the vast majority
-        // of audio formats. Load both of these types of tags into separate maps, letting the
-        // "source of truth" be the last of a particular tag in a file.
-        for (i in 0 until metadata.length()) {
-            when (val tag = metadata[i]) {
-                is TextInformationFrame -> {
-                    // Map TXXX frames differently so we can specifically index by their
-                    // descriptions.
-                    val id = tag.description?.let { "TXXX:${it.sanitize()}" } ?: tag.id.sanitize()
-                    val values = tag.values.map { it.sanitize() }.correctWhitespace()
-                    if (values.isNotEmpty()) {
-                        id3v2Tags[id] = values
-                    }
-                }
-                is VorbisComment -> {
-                    // Vorbis comment keys can be in any case, make them uppercase for simplicity.
-                    val id = tag.key.sanitize().uppercase()
-                    val value = tag.value.sanitize().correctWhitespace()
-                    if (value != null) {
-                        vorbisTags.getOrPut(id) { mutableListOf() }.add(value)
-                    }
-                }
-            }
-        }
-
-        when {
-            vorbisTags.isEmpty() -> populateWithId3v2(id3v2Tags)
-            id3v2Tags.isEmpty() -> populateWithVorbis(vorbisTags)
-            else -> {
-                // Some formats (like FLAC) can contain both ID3v2 and Vorbis, so we apply
-                // them both with priority given to vorbis.
-                populateWithId3v2(id3v2Tags)
-                populateWithVorbis(vorbisTags)
-            }
-        }
-    }
-
     /**
      * Complete this instance's [Song.Raw] with ID3v2 Text Identification Frames.
      * @param textFrames A mapping between ID3v2 Text Identification Frame IDs and one or more
@@ -224,15 +177,15 @@ class Task(context: Context, private val raw: Song.Raw) {
      */
     private fun populateWithId3v2(textFrames: Map<String, List<String>>) {
         // Song
-        textFrames["TXXX:MusicBrainz Release Track Id"]?.let { raw.musicBrainzId = it[0] }
+        textFrames["TXXX:musicbrainz release track id"]?.let { raw.musicBrainzId = it[0] }
         textFrames["TIT2"]?.let { raw.name = it[0] }
         textFrames["TSOT"]?.let { raw.sortName = it[0] }
 
         // Track. Only parse out the track number and ignore the total tracks value.
-        textFrames["TRCK"]?.run { get(0).parseId3v2Position() }?.let { raw.track = it }
+        textFrames["TRCK"]?.run { first().parseId3v2Position() }?.let { raw.track = it }
 
         // Disc. Only parse out the disc number and ignore the total discs value.
-        textFrames["TPOS"]?.run { get(0).parseId3v2Position() }?.let { raw.disc = it }
+        textFrames["TPOS"]?.run { first().parseId3v2Position() }?.let { raw.disc = it }
 
         // Dates are somewhat complicated, as not only did their semantics change from a flat year
         // value in ID3v2.3 to a full ISO-8601 date in ID3v2.4, but there are also a variety of
@@ -243,27 +196,27 @@ class Task(context: Context, private val raw: Song.Raw) {
         // 3. ID3v2.4 Release Date, as it is the second most common date type
         // 4. ID3v2.3 Original Date, as it is like #1
         // 5. ID3v2.3 Release Year, as it is the most common date type
-        (textFrames["TDOR"]?.run { Date.from(get(0)) }
+        (textFrames["TDOR"]?.run { Date.from(first()) }
-                ?: textFrames["TDRC"]?.run { Date.from(get(0)) }
+                ?: textFrames["TDRC"]?.run { Date.from(first()) }
-                    ?: textFrames["TDRL"]?.run { Date.from(get(0)) }
+                    ?: textFrames["TDRL"]?.run { Date.from(first()) }
                     ?: parseId3v23Date(textFrames))
             ?.let { raw.date = it }
 
         // Album
-        textFrames["TXXX:MusicBrainz Album Id"]?.let { raw.albumMusicBrainzId = it[0] }
+        textFrames["TXXX:musicbrainz album id"]?.let { raw.albumMusicBrainzId = it[0] }
         textFrames["TALB"]?.let { raw.albumName = it[0] }
         textFrames["TSOA"]?.let { raw.albumSortName = it[0] }
-        (textFrames["TXXX:MusicBrainz Album Type"] ?: textFrames["GRP1"])?.let {
+        (textFrames["TXXX:musicbrainz album type"] ?: textFrames["GRP1"])?.let {
             raw.albumTypes = it
         }
 
         // Artist
-        textFrames["TXXX:MusicBrainz Artist Id"]?.let { raw.artistMusicBrainzIds = it }
+        textFrames["TXXX:musicbrainz artist id"]?.let { raw.artistMusicBrainzIds = it }
         textFrames["TPE1"]?.let { raw.artistNames = it }
         textFrames["TSOP"]?.let { raw.artistSortNames = it }
 
         // Album artist
-        textFrames["TXXX:MusicBrainz Album Artist Id"]?.let { raw.albumArtistMusicBrainzIds = it }
+        textFrames["TXXX:musicbrainz album artist id"]?.let { raw.albumArtistMusicBrainzIds = it }
         textFrames["TPE2"]?.let { raw.albumArtistNames = it }
         textFrames["TSO2"]?.let { raw.albumArtistSortNames = it }
 
@@ -284,8 +237,8 @@ class Task(context: Context, private val raw: Song.Raw) {
         // Assume that TDAT/TIME can refer to TYER or TORY depending on if TORY
         // is present.
         val year =
-            textFrames["TORY"]?.run { get(0).toIntOrNull() }
+            textFrames["TORY"]?.run { first().toIntOrNull() }
-                ?: textFrames["TYER"]?.run { get(0).toIntOrNull() } ?: return null
+                ?: textFrames["TYER"]?.run { first().toIntOrNull() } ?: return null
 
         val tdat = textFrames["TDAT"]
         return if (tdat != null && tdat[0].length == 4 && tdat[0].isDigitsOnly()) {
@@ -319,17 +272,17 @@ class Task(context: Context, private val raw: Song.Raw) {
      */
     private fun populateWithVorbis(comments: Map<String, List<String>>) {
         // Song
-        comments["MUSICBRAINZ_RELEASETRACKID"]?.let { raw.musicBrainzId = it[0] }
+        comments["musicbrainz_releasetrackid"]?.let { raw.musicBrainzId = it[0] }
-        comments["TITLE"]?.let { raw.name = it[0] }
+        comments["title"]?.let { raw.name = it[0] }
-        comments["TITLESORT"]?.let { raw.sortName = it[0] }
+        comments["titlesort"]?.let { raw.sortName = it[0] }
 
         // Track. The total tracks value is in a different comment, so we can just
         // convert the entirety of this comment into a number.
-        comments["TRACKNUMBER"]?.run { get(0).toIntOrNull() }?.let { raw.track = it }
+        comments["tracknumber"]?.run { first().toIntOrNull() }?.let { raw.track = it }
 
         // Disc. The total discs value is in a different comment, so we can just
         // convert the entirety of this comment into a number.
-        comments["DISCNUMBER"]?.run { get(0).toIntOrNull() }?.let { raw.disc = it }
+        comments["discnumber"]?.run { first().toIntOrNull() }?.let { raw.disc = it }
 
         // Vorbis dates are less complicated, but there are still several types
         // Our hierarchy for dates is as such:
@@ -337,35 +290,28 @@ class Task(context: Context, private val raw: Song.Raw) {
         // 2. Date, as it is the most common date type
         // 3. Year, as old vorbis tags tended to use this (I know this because it's the only
         // date tag that android supports, so it must be 15 years old or more!)
-        (comments["ORIGINALDATE"]?.run { Date.from(get(0)) }
+        (comments["originaldate"]?.run { Date.from(first()) }
-                ?: comments["DATE"]?.run { Date.from(get(0)) }
+                ?: comments["date"]?.run { Date.from(first()) }
-                    ?: comments["YEAR"]?.run { get(0).toIntOrNull()?.let(Date::from) })
+                    ?: comments["year"]?.run { first().toIntOrNull()?.let(Date::from) })
             ?.let { raw.date = it }
 
         // Album
-        comments["MUSICBRAINZ_ALBUMID"]?.let { raw.albumMusicBrainzId = it[0] }
+        comments["musicbrainz_albumid"]?.let { raw.albumMusicBrainzId = it[0] }
-        comments["ALBUM"]?.let { raw.albumName = it[0] }
+        comments["album"]?.let { raw.albumName = it[0] }
-        comments["ALBUMSORT"]?.let { raw.albumSortName = it[0] }
+        comments["albumsort"]?.let { raw.albumSortName = it[0] }
-        comments["RELEASETYPE"]?.let { raw.albumTypes = it }
+        comments["releasetype"]?.let { raw.albumTypes = it }
 
         // Artist
-        comments["MUSICBRAINZ_ARTISTID"]?.let { raw.artistMusicBrainzIds = it }
+        comments["musicbrainz_artistid"]?.let { raw.artistMusicBrainzIds = it }
-        comments["ARTIST"]?.let { raw.artistNames = it }
+        comments["artist"]?.let { raw.artistNames = it }
-        comments["ARTISTSORT"]?.let { raw.artistSortNames = it }
+        comments["artistsort"]?.let { raw.artistSortNames = it }
 
         // Album artist
-        comments["MUSICBRAINZ_ALBUMARTISTID"]?.let { raw.albumArtistMusicBrainzIds = it }
+        comments["musicbrainz_albumartistid"]?.let { raw.albumArtistMusicBrainzIds = it }
-        comments["ALBUMARTIST"]?.let { raw.albumArtistNames = it }
+        comments["albumartist"]?.let { raw.albumArtistNames = it }
-        comments["ALBUMARTISTSORT"]?.let { raw.albumArtistSortNames = it }
+        comments["albumartistsort"]?.let { raw.albumArtistSortNames = it }
 
         // Genre
         comments["GENRE"]?.let { raw.genreNames = it }
     }
-
-    /**
-     * Copies and sanitizes a possibly native/non-UTF-8 string.
-     * @return A new string allocated in a memory-safe manner with any UTF-8 errors replaced with
-     * the Unicode replacement byte sequence.
-     */
-    private fun String.sanitize() = String(encodeToByteArray())
 }

app/src/main/java/org/oxycblt/auxio/music/extractor/Tags.kt

@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2023 Auxio Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+ 
+package org.oxycblt.auxio.music.extractor
+
+import com.google.android.exoplayer2.metadata.Metadata
+import com.google.android.exoplayer2.metadata.id3.InternalFrame
+import com.google.android.exoplayer2.metadata.id3.TextInformationFrame
+import com.google.android.exoplayer2.metadata.vorbis.VorbisComment
+import org.oxycblt.auxio.music.parsing.correctWhitespace
+
+/**
+ * Processing wrapper for [Metadata] that allows access to more organized metadata.
+ * @param metadata The [Metadata] to wrap.
+ * @author Alexander Capehart (OxygenCobalt)
+ */
+class Tags(metadata: Metadata) {
+    private val _id3v2 = mutableMapOf<String, List<String>>()
+    /** The ID3v2 text identification frames found in the file. Can have more than one value. */
+    val id3v2: Map<String, List<String>>
+        get() = _id3v2
+
+    private val _vorbis = mutableMapOf<String, MutableList<String>>()
+    /** The vorbis comments found in the file. Can have more than one value. */
+    val vorbis: Map<String, List<String>>
+        get() = _vorbis
+
+    init {
+        // ExoPlayer only exposes ID3v2 and Vorbis metadata, which constitutes the vast majority
+        // of audio formats. Load both of these types of tags into separate maps, letting the
+        // "source of truth" be the last of a particular tag in a file.
+        for (i in 0 until metadata.length()) {
+            when (val tag = metadata[i]) {
+                is TextInformationFrame -> {
+                    // Map TXXX frames differently so we can specifically index by their
+                    // descriptions.
+                    val id =
+                        tag.description?.let { "TXXX:${it.sanitize().lowercase()}" }
+                            ?: tag.id.sanitize()
+                    val values = tag.values.map { it.sanitize() }.correctWhitespace()
+                    if (values.isNotEmpty()) {
+                        _id3v2[id] = values
+                    }
+                }
+                is InternalFrame -> {
+                    // Most MP4 metadata atoms map to ID3v2 text frames, except for the ---- atom,
+                    // which has it's own frame. Map this to TXXX, it's rough ID3v2 equivalent.
+                    val id = "TXXX:${tag.description.sanitize().lowercase()}"
+                    val value = tag.text
+                    if (value.isNotEmpty()) {
+                        _id3v2[id] = listOf(value)
+                    }
+                }
+                is VorbisComment -> {
+                    // Vorbis comment keys can be in any case, make them uppercase for simplicity.
+                    val id = tag.key.sanitize().lowercase()
+                    val value = tag.value.sanitize().correctWhitespace()
+                    if (value != null) {
+                        _vorbis.getOrPut(id) { mutableListOf() }.add(value)
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Copies and sanitizes a possibly invalid string outputted from ExoPlayer.
+     * @return A new string allocated in a memory-safe manner with any UTF-8 errors replaced with
+     * the Unicode replacement byte sequence.
+     */
+    private fun String.sanitize() = String(encodeToByteArray())
+}

app/src/main/java/org/oxycblt/auxio/music/filesystem/DirectoryAdapter.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.music.storage
+package org.oxycblt.auxio.music.filesystem
 
 import android.view.View
 import android.view.ViewGroup

app/src/main/java/org/oxycblt/auxio/music/filesystem/Filesystem.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.music.storage
+package org.oxycblt.auxio.music.filesystem
 
 import android.content.Context
 import android.media.MediaFormat

app/src/main/java/org/oxycblt/auxio/music/filesystem/FilesystemUtil.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.music.storage
+package org.oxycblt.auxio.music.filesystem
 
 import android.annotation.SuppressLint
 import android.content.ContentResolver

app/src/main/java/org/oxycblt/auxio/music/filesystem/MusicDirsDialog.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.music.storage
+package org.oxycblt.auxio.music.filesystem
 
 import android.net.Uri
 import android.os.Bundle
@@ -31,7 +31,6 @@ import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.DialogMusicDirsBinding
 import org.oxycblt.auxio.settings.Settings
 import org.oxycblt.auxio.ui.ViewBindingDialogFragment
-import org.oxycblt.auxio.util.context
 import org.oxycblt.auxio.util.getSystemServiceCompat
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.showToast

app/src/main/java/org/oxycblt/auxio/music/parsing/ParsingUtil.kt

@@ -31,7 +31,7 @@ import org.oxycblt.auxio.util.nonZeroOrNull
  */
 fun List<String>.parseMultiValue(settings: Settings) =
     if (size == 1) {
-        get(0).maybeParseBySeparators(settings)
+        first().maybeParseBySeparators(settings)
     } else {
         // Nothing to do.
         this
@@ -124,7 +124,7 @@ fun String.parseId3v2Position() = split('/', limit = 2)[0].toIntOrNull()?.nonZer
  */
 fun List<String>.parseId3GenreNames(settings: Settings) =
     if (size == 1) {
-        get(0).parseId3MultiValueGenre(settings)
+        first().parseId3MultiValueGenre(settings)
     } else {
         // Nothing to split, just map any ID3v1 genres to their name counterparts.
         map { it.parseId3v1Genre() ?: it }

app/src/main/java/org/oxycblt/auxio/music/parsing/Separators.kt

@@ -1,3 +1,20 @@
+/*
+ * Copyright (c) 2023 Auxio Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+ 
 package org.oxycblt.auxio.music.parsing
 
 /**

app/src/main/java/org/oxycblt/auxio/music/system/IndexerService.kt

@@ -34,7 +34,7 @@ import kotlinx.coroutines.launch
 import org.oxycblt.auxio.BuildConfig
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.music.MusicStore
-import org.oxycblt.auxio.music.storage.contentResolverSafe
+import org.oxycblt.auxio.music.filesystem.contentResolverSafe
 import org.oxycblt.auxio.playback.state.PlaybackStateManager
 import org.oxycblt.auxio.service.ForegroundManager
 import org.oxycblt.auxio.settings.Settings

app/src/main/java/org/oxycblt/auxio/playback/replaygain/ReplayGainAudioProcessor.kt

@@ -18,33 +18,38 @@
 package org.oxycblt.auxio.playback.replaygain
 
 import android.content.Context
+import android.content.SharedPreferences
 import com.google.android.exoplayer2.C
+import com.google.android.exoplayer2.Format
+import com.google.android.exoplayer2.Player
+import com.google.android.exoplayer2.Tracks
 import com.google.android.exoplayer2.audio.AudioProcessor
 import com.google.android.exoplayer2.audio.BaseAudioProcessor
-import com.google.android.exoplayer2.metadata.Metadata
+import com.google.android.exoplayer2.util.MimeTypes
-import com.google.android.exoplayer2.metadata.id3.InternalFrame
-import com.google.android.exoplayer2.metadata.id3.TextInformationFrame
-import com.google.android.exoplayer2.metadata.vorbis.VorbisComment
 import java.nio.ByteBuffer
 import kotlin.math.pow
+import org.oxycblt.auxio.R
 import org.oxycblt.auxio.music.Album
+import org.oxycblt.auxio.music.extractor.Tags
 import org.oxycblt.auxio.playback.state.PlaybackStateManager
 import org.oxycblt.auxio.settings.Settings
 import org.oxycblt.auxio.util.logD
-import org.oxycblt.auxio.util.unlikelyToBeNull
 
 /**
  * An [AudioProcessor] that handles ReplayGain values and their amplification of the audio stream.
  * Instead of leveraging the volume attribute like other implementations, this system manipulates
  * the bitstream itself to modify the volume, which allows the use of positive ReplayGain values.
  *
- * Note: This instance must be updated with a new [Metadata] every time the active track chamges.
+ * Note: This audio processor must be attached to a respective [Player] instance as a
+ * [Player.Listener] to function properly.
  *
  * @author Alexander Capehart (OxygenCobalt)
  */
-class ReplayGainAudioProcessor(context: Context) : BaseAudioProcessor() {
+class ReplayGainAudioProcessor(private val context: Context) :
+    BaseAudioProcessor(), Player.Listener, SharedPreferences.OnSharedPreferenceChangeListener {
     private val playbackManager = PlaybackStateManager.getInstance()
     private val settings = Settings(context)
+    private var lastFormat: Format? = null
 
     private var volume = 1f
         set(value) {
@@ -53,20 +58,69 @@ class ReplayGainAudioProcessor(context: Context) : BaseAudioProcessor() {
             flush()
         }
 
+    /**
+     * Add this instance to the components required for it to function correctly.
+     * @param player The [Player] to attach to. Should already have this instance as an audio
+     * processor.
+     */
+    fun addToListeners(player: Player) {
+        player.addListener(this)
+        settings.addListener(this)
+    }
+
+    /**
+     * Remove this instance from the components required for it to function correctly.
+     * @param player The [Player] to detach from. Should already have this instance as an audio
+     * processor.
+     */
+    fun releaseFromListeners(player: Player) {
+        player.removeListener(this)
+        settings.removeListener(this)
+    }
+
+    // --- OVERRIDES ---
+
+    override fun onTracksChanged(tracks: Tracks) {
+        super.onTracksChanged(tracks)
+        // Try to find the currently playing track so we can update the ReplayGain adjustment
+        // based on it.
+        for (group in tracks.groups) {
+            if (group.isSelected) {
+                for (i in 0 until group.length) {
+                    if (group.isTrackSelected(i)) {
+                        applyReplayGain(group.getTrackFormat(i))
+                        return
+                    }
+                }
+            }
+        }
+        // Nothing selected, apply nothing
+        applyReplayGain(null)
+    }
+
+    override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences?, key: String?) {
+        if (key == context.getString(R.string.set_key_replay_gain) ||
+            key == context.getString(R.string.set_key_pre_amp_with) ||
+            key == context.getString(R.string.set_key_pre_amp_without)) {
+            // ReplayGain changed, we need to set it up again.
+            applyReplayGain(lastFormat)
+        }
+    }
+
     // --- REPLAYGAIN PARSING ---
 
     /**
-     * Updates the volume adjustment based on the given [Metadata].
+     * Updates the volume adjustment based on the given [Format].
-     * @param metadata The [Metadata] of the currently playing track, or null if the track has no
+     * @param format The [Format] of the currently playing track, or null if nothing is playing.
-     * [Metadata].
      */
-    fun applyReplayGain(metadata: Metadata?) {
+    private fun applyReplayGain(format: Format?) {
-        // TODO: Allow this to automatically obtain it's own [Metadata].
+        lastFormat = format
-        val gain = metadata?.let(::parseReplayGain)
+        val gain = parseReplayGain(format ?: return)
         val preAmp = settings.replayGainPreAmp
 
         val adjust =
             if (gain != null) {
+                logD("Found ReplayGain adjustment $gain")
                 // ReplayGain is configurable, so determine what to do based off of the mode.
                 val useAlbumGain =
                     when (settings.replayGainMode) {
@@ -109,104 +163,58 @@ class ReplayGainAudioProcessor(context: Context) : BaseAudioProcessor() {
     }
 
     /**
-     * Parse ReplayGain information from the given [Metadata].
+     * Parse ReplayGain information from the given [Format].
-     * @param metadata The [Metadata] to parse.
+     * @param format The [Format] to parse.
-     * @return A [Gain] adjustment, or null if there was no adjustments to parse.
+     * @return A [Adjustment] adjustment, or null if there were no valid adjustments.
      */
-    private fun parseReplayGain(metadata: Metadata): Gain? {
+    private fun parseReplayGain(format: Format): Adjustment? {
-        // TODO: Unify this parser with the music parser? They both grok Metadata.
+        val tags = Tags(format.metadata ?: return null)
-
         var trackGain = 0f
         var albumGain = 0f
-        var found = false
 
-        val tags = mutableListOf<GainTag>()
+        // Most ReplayGain tags are formatted as a simple decibel adjustment in a custom
-
+        // replaygain_*_gain tag.
-        for (i in 0 until metadata.length()) {
+        if (format.sampleMimeType != MimeTypes.AUDIO_OPUS) {
-            val entry = metadata.get(i)
+            tags.id3v2["TXXX:$TAG_RG_TRACK_GAIN"]
-
+                ?.run { first().parseReplayGainAdjustment() }
-            val key: String?
+                ?.let { trackGain = it }
-            val value: String
+            tags.id3v2["TXXX:$TAG_RG_ALBUM_GAIN"]
-
+                ?.run { first().parseReplayGainAdjustment() }
-            when (entry) {
+                ?.let { albumGain = it }
-                // ID3v2 text information frame, usually these are formatted in lowercase
+            tags.vorbis[TAG_RG_ALBUM_GAIN]
-                // (like "replaygain_track_gain"), but can also be uppercase. Make sure that
+                ?.run { first().parseReplayGainAdjustment() }
-                // capitalization is consistent before continuing.
+                ?.let { trackGain = it }
-                is TextInformationFrame -> {
+            tags.vorbis[TAG_RG_TRACK_GAIN]
-                    key = entry.description
+                ?.run { first().parseReplayGainAdjustment() }
-                    value = entry.values[0]
+                ?.let { albumGain = it }
-                }
+        } else {
-                // Internal Frame. This is actually MP4's "----" atom, but mapped to an ID3v2
+            // Opus has it's own "r128_*_gain" ReplayGain specification, which requires dividing the
-                // frame by ExoPlayer (presumably to reduce duplication).
+            // adjustment by 256 to get the gain. This is used alongside the base adjustment
-                is InternalFrame -> {
+            // intrinsic to the format to create the normalized adjustment. That base adjustment
-                    key = entry.description
+            // is already handled by the media  framework, so we just need to apply the more
-                    value = entry.text
+            // specific adjustments.
-                }
+            tags.vorbis[TAG_R128_TRACK_GAIN]
-                // Vorbis comment. These are nearly always uppercase, so a check for such is
+                ?.run { first().parseReplayGainAdjustment() }
-                // skipped.
+                ?.let { trackGain = it / 256f }
-                is VorbisComment -> {
+            tags.vorbis[TAG_R128_ALBUM_GAIN]
-                    key = entry.key
+                ?.run { first().parseReplayGainAdjustment() }
-                    value = entry.value
+                ?.let { albumGain = it / 256f }
-                }
-                else -> continue
         }
 
-            if (key in REPLAY_GAIN_TAGS) {
+        return if (trackGain != 0f || albumGain != 0f) {
-                // Grok a float from a ReplayGain tag by removing everything that is not 0-9, ,
+            Adjustment(trackGain, albumGain)
-                // or -.
-                // Derived from vanilla music: https://github.com/vanilla-music/vanilla
-                val gainValue =
-                    try {
-                        value.replace(Regex("[^\\d.-]"), "").toFloat()
-                    } catch (e: Exception) {
-                        0f
-                    }
-
-                tags.add(GainTag(unlikelyToBeNull(key), gainValue))
-            }
-        }
-
-        // Case 1: Normal ReplayGain, most commonly found on MPEG files.
-        tags
-            .findLast { tag -> tag.key.equals(TAG_RG_TRACK, ignoreCase = true) }
-            ?.let { tag ->
-                trackGain = tag.value
-                found = true
-            }
-
-        tags
-            .findLast { tag -> tag.key.equals(TAG_RG_ALBUM, ignoreCase = true) }
-            ?.let { tag ->
-                albumGain = tag.value
-                found = true
-            }
-
-        // Case 2: R128 ReplayGain, most commonly found on FLAC files and other lossless
-        // encodings to increase precision in volume adjustments.
-        // While technically there is the R128 base gain in Opus files, that is automatically
-        // applied by the media framework [which ExoPlayer relies on]. The only reason we would
-        // want to read it is to zero previous ReplayGain values for being invalid, however there
-        // is no demand to fix that edge case right now.
-        tags
-            .findLast { tag -> tag.key.equals(R128_TRACK, ignoreCase = true) }
-            ?.let { tag ->
-                trackGain += tag.value / 256f
-                found = true
-            }
-
-        tags
-            .findLast { tag -> tag.key.equals(R128_ALBUM, ignoreCase = true) }
-            ?.let { tag ->
-                albumGain += tag.value / 256f
-                found = true
-            }
-
-        return if (found) {
-            Gain(trackGain, albumGain)
         } else {
             null
         }
     }
+
+    /**
+     * Parse a ReplayGain adjustment into a float value.
+     * @return A parsed adjustment float, or null if the adjustment had invalid formatting.
+     */
+    private fun String.parseReplayGainAdjustment() =
+        replace(REPLAYGAIN_ADJUSTMENT_FILTER_REGEX, "").toFloatOrNull()
+
     // --- AUDIO PROCESSOR IMPLEMENTATION ---
 
     override fun onConfigure(
@@ -271,21 +279,18 @@ class ReplayGainAudioProcessor(context: Context) : BaseAudioProcessor() {
      * @param track The track adjustment (in dB), or 0 if it is not present.
      * @param album The album adjustment (in dB), or 0 if it is not present.
      */
-    private data class Gain(val track: Float, val album: Float)
+    private data class Adjustment(val track: Float, val album: Float)
-
-    /**
-     * A raw ReplayGain adjustment.
-     * @param key The tag's key.
-     * @param value The tag's adjustment, in dB.
-     */
-    private data class GainTag(val key: String, val value: Float)
-    // TODO: Try to phase this out
 
     private companion object {
-        const val TAG_RG_TRACK = "replaygain_track_gain"
+        const val TAG_RG_TRACK_GAIN = "replaygain_track_gain"
-        const val TAG_RG_ALBUM = "replaygain_album_gain"
+        const val TAG_RG_ALBUM_GAIN = "replaygain_album_gain"
-        const val R128_TRACK = "r128_track_gain"
+        const val TAG_R128_TRACK_GAIN = "r128_track_gain"
-        const val R128_ALBUM = "r128_album_gain"
+        const val TAG_R128_ALBUM_GAIN = "r128_album_gain"
-        val REPLAY_GAIN_TAGS = arrayOf(TAG_RG_TRACK, TAG_RG_ALBUM, R128_ALBUM, R128_TRACK)
+
+        /**
+         * Matches non-float information from ReplayGain adjustments. Derived from vanilla music:
+         * https://github.com/vanilla-music/vanilla
+         */
+        val REPLAYGAIN_ADJUSTMENT_FILTER_REGEX = Regex("[^\\d.-]")
     }
 }

app/src/main/java/org/oxycblt/auxio/playback/system/PlaybackService.kt

@@ -22,7 +22,6 @@ import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
 import android.content.IntentFilter
-import android.content.SharedPreferences
 import android.media.AudioManager
 import android.media.audiofx.AudioEffect
 import android.os.IBinder
@@ -32,7 +31,6 @@ import com.google.android.exoplayer2.MediaItem
 import com.google.android.exoplayer2.PlaybackException
 import com.google.android.exoplayer2.Player
 import com.google.android.exoplayer2.RenderersFactory
-import com.google.android.exoplayer2.Tracks
 import com.google.android.exoplayer2.audio.AudioAttributes
 import com.google.android.exoplayer2.audio.AudioCapabilities
 import com.google.android.exoplayer2.audio.MediaCodecAudioRenderer
@@ -45,7 +43,6 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.launch
 import org.oxycblt.auxio.BuildConfig
-import org.oxycblt.auxio.R
 import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.replaygain.ReplayGainAudioProcessor
@@ -81,8 +78,7 @@ class PlaybackService :
     Player.Listener,
     InternalPlayer,
     MediaSessionComponent.Listener,
-    MusicStore.Listener,
+    MusicStore.Listener {
-    SharedPreferences.OnSharedPreferenceChangeListener {
     // Player components
     private lateinit var player: ExoPlayer
     private lateinit var replayGainProcessor: ReplayGainAudioProcessor
@@ -144,9 +140,9 @@ class PlaybackService :
                     true)
                 .build()
                 .also { it.addListener(this) }
+        replayGainProcessor.addToListeners(player)
         // Initialize the core service components
         settings = Settings(this)
-        settings.addListener(this)
         foregroundManager = ForegroundManager(this)
         // Initialize any listener-dependent components last as we wouldn't want a listener race
         // condition to cause us to load music before we were fully initialize.
@@ -187,7 +183,6 @@ class PlaybackService :
         super.onDestroy()
 
         foregroundManager.release()
-        settings.removeListener(this)
 
         // Pause just in case this destruction was unexpected.
         playbackManager.setPlaying(false)
@@ -200,6 +195,7 @@ class PlaybackService :
         widgetComponent.release()
         mediaSessionComponent.release()
 
+        replayGainProcessor.releaseFromListeners(player)
         player.release()
         if (openAudioEffectSession) {
             // Make sure to close the audio session when we release the player.
@@ -304,24 +300,6 @@ class PlaybackService :
         playbackManager.next()
     }
 
-    override fun onTracksChanged(tracks: Tracks) {
-        super.onTracksChanged(tracks)
-        // Try to find the currently playing track so we can update ReplayGainAudioProcessor
-        // with it.
-        for (group in tracks.groups) {
-            if (group.isSelected) {
-                for (i in 0 until group.length) {
-                    if (group.isTrackSelected(i)) {
-                        replayGainProcessor.applyReplayGain(group.getTrackFormat(i).metadata)
-                        break
-                    }
-                }
-
-                break
-            }
-        }
-    }
-
     // --- MUSICSTORE OVERRIDES ---
 
     override fun onLibraryChanged(library: MusicStore.Library?) {
@@ -331,17 +309,6 @@ class PlaybackService :
         }
     }
 
-    // --- SETTINGS OVERRIDES ---
-
-    override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences, key: String) {
-        if (key == getString(R.string.set_key_replay_gain) ||
-            key == getString(R.string.set_key_pre_amp_with) ||
-            key == getString(R.string.set_key_pre_amp_without)) {
-            // ReplayGain changed, we need to set it up again.
-            onTracksChanged(player.currentTracks)
-        }
-    }
-
     // --- OTHER FUNCTIONS ---
 
     private fun broadcastAudioEffectAction(event: String) {

app/src/main/java/org/oxycblt/auxio/settings/Settings.kt

@@ -31,8 +31,8 @@ import org.oxycblt.auxio.home.tabs.Tab
 import org.oxycblt.auxio.image.CoverMode
 import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.Sort
-import org.oxycblt.auxio.music.storage.Directory
+import org.oxycblt.auxio.music.filesystem.Directory
-import org.oxycblt.auxio.music.storage.MusicDirectories
+import org.oxycblt.auxio.music.filesystem.MusicDirectories
 import org.oxycblt.auxio.playback.ActionMode
 import org.oxycblt.auxio.playback.replaygain.ReplayGainMode
 import org.oxycblt.auxio.playback.replaygain.ReplayGainPreAmp

app/src/main/res/navigation/nav_main.xml

@@ -106,7 +106,7 @@
         tools:layout="@layout/dialog_pre_amp" />
     <dialog
         android:id="@+id/music_dirs_dialog"
-        android:name="org.oxycblt.auxio.music.storage.MusicDirsDialog"
+        android:name="org.oxycblt.auxio.music.filesystem.MusicDirsDialog"
         android:label="music_dirs_dialog"
         tools:layout="@layout/dialog_music_dirs" />
     <dialog