playback: ignore zeroed replaygain tags

Ignore ReplayGain adjustments that are just 0 dB.

CHANGELOG.md

@@ -11,6 +11,7 @@
 - Disc number is no longer mis-aligned when no subtitle is present
 - Fixed selection not updating when playlists are changed
 - Fixed duplicate albums appearing in certain cases
+- Fixed ReplayGain adjustment not applying at the start of a song in certain cases
 
 ## 3.1.1
 

app/src/main/java/org/oxycblt/auxio/music/metadata/TagWorker.kt

@@ -30,6 +30,7 @@ import org.oxycblt.auxio.music.fs.toAudioUri
 import org.oxycblt.auxio.music.info.Date
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.logW
+import org.oxycblt.auxio.util.nonZeroOrNull
 
 /**
  * An processing abstraction over the [MetadataRetriever] and [TextTags] workflow that operates on
@@ -300,7 +301,7 @@ private class TagWorkerImpl(
      * @return A parsed adjustment float, or null if the adjustment had invalid formatting.
      */
     private fun List<String>.parseReplayGainAdjustment() =
-        first().replace(REPLAYGAIN_ADJUSTMENT_FILTER_REGEX, "").toFloatOrNull()
+        first().replace(REPLAYGAIN_ADJUSTMENT_FILTER_REGEX, "").toFloatOrNull()?.nonZeroOrNull()
 
     private companion object {
         val COMPILATION_ALBUM_ARTISTS = listOf("Various Artists")