Added setting for persisting subtitles across multiple videos when the same language exists.

app/src/main/java/com/futo/platformplayer/Settings.kt

@@ -408,6 +408,10 @@ class Settings : FragmentedStorageFileJson() {
                 else -> null
             }
         }
+
+        @FormField(R.string.sticky_subtitles, FieldForm.TOGGLE, R.string.sticky_subtitles_description, -1)
+        var stickySubtitles: Boolean = true;
+
         @FormField(R.string.prefer_original_audio, FieldForm.TOGGLE, R.string.prefer_original_audio_description, -1)
         var preferOriginalAudio: Boolean = true;
 

app/src/main/java/com/futo/platformplayer/api/media/models/streams/sources/HLSVariantUrlSource.kt

@@ -41,6 +41,7 @@ class HLSVariantSubtitleUrlSource(
     override val format: String,
 ) : ISubtitleSource {
     override val hasFetch: Boolean = false
+    override val language: String? = null
 
     override fun getSubtitles(): String? {
         return null

app/src/main/java/com/futo/platformplayer/api/media/models/streams/sources/LocalSubtitleSource.kt

@@ -9,13 +9,15 @@ class LocalSubtitleSource : ISubtitleSource {
     override val name: String;
     override val url: String?;
     override val format: String?;
+    override val language: String?
     override val hasFetch: Boolean get() = false;
 
     val filePath: String;
 
-    constructor(name: String, format: String?, filePath: String) {
+    constructor(name: String, language: String?, format: String?, filePath: String) {
         this.name = name;
         this.format = format;
+        this.language = language
         this.filePath = filePath;
         this.url = Uri.fromFile(File(filePath)).toString();
     }
@@ -32,6 +34,7 @@ class LocalSubtitleSource : ISubtitleSource {
         fun fromSource(source: SubtitleRawSource, path: String): LocalSubtitleSource {
             return LocalSubtitleSource(
                 source.name,
+                source.language,
                 source.format,
                 path
             );

app/src/main/java/com/futo/platformplayer/api/media/models/streams/sources/SubtitleRawSource.kt

@@ -6,6 +6,7 @@ import com.futo.platformplayer.api.media.models.subtitles.ISubtitleSource
 @kotlinx.serialization.Serializable
 class SubtitleRawSource(
     override val name: String,
+    override val language: String?,
     override val format: String?,
     val _subtitles: String,
     override val url: String? = null,

app/src/main/java/com/futo/platformplayer/api/media/models/subtitles/ISubtitleSource.kt

@@ -7,6 +7,7 @@ interface ISubtitleSource {
     val url: String?;
     val format: String?;
     val hasFetch: Boolean;
+    val language: String?
 
     fun getSubtitles(): String?;
 

app/src/main/java/com/futo/platformplayer/api/media/platforms/js/models/JSSubtitleSource.kt

@@ -22,6 +22,7 @@ class JSSubtitleSource : ISubtitleSource {
     override val name: String;
     override val url: String?;
     override val format: String?;
+    override val language: String?
     override val hasFetch: Boolean;
 
     constructor(config: SourcePluginConfig, v8Value: V8ValueObject) {
@@ -29,6 +30,7 @@ class JSSubtitleSource : ISubtitleSource {
 
         val context = "JSSubtitles";
         name = v8Value.getOrThrow(config, "name", context, false);
+        language = v8Value.getOrThrow(config, "language", context, false);
         url = v8Value.getOrThrow(config, "url", context, true);
         format = v8Value.getOrThrow(config, "format", context, true);
         hasFetch = v8Value.has("getSubtitles");

app/src/main/java/com/futo/platformplayer/fragment/mainactivity/main/VideoDetailView.kt

@@ -357,6 +357,7 @@ class VideoDetailView : ConstraintLayout {
         Pair(-5 * 60, 30), //around 5 minutes, try every 30 seconds
         Pair(0, 10) //around live, try every 10 seconds
     );
+    private var _subtitleLanguage: String? = null
 
     @androidx.annotation.OptIn(UnstableApi::class)
     constructor(context: Context, attrs : AttributeSet? = null) : super(context, attrs) {
@@ -1975,7 +1976,7 @@ class VideoDetailView : ConstraintLayout {
         try {
             val videoSource = _lastVideoSource ?: _player.getPreferredVideoSource(video, Settings.instance.playback.getCurrentPreferredQualityPixelCount());
             val audioSource = _lastAudioSource ?: _player.getPreferredAudioSource(video, Settings.instance.playback.getPrimaryLanguage(context));
-            val subtitleSource = _lastSubtitleSource ?: (if(video is VideoLocal) video.subtitlesSources.firstOrNull() else null);
+            val subtitleSource = _lastSubtitleSource ?: (if (Settings.instance.playback.stickySubtitles) _player.getPreferredSubtitleSource(video, _subtitleLanguage) else null) ?: (if(video is VideoLocal) video.subtitlesSources.firstOrNull() else null);
             Logger.i(TAG, "loadCurrentVideo(videoSource=$videoSource, audioSource=$audioSource, subtitleSource=$subtitleSource, resumePositionMs=$resumePositionMs)")
 
             if(videoSource == null && audioSource == null) {
@@ -2659,6 +2660,7 @@ class VideoDetailView : ConstraintLayout {
             }
         }
         _lastSubtitleSource = toSet;
+        _subtitleLanguage = toSet?.language
     }
 
     private fun handleUnavailableVideo(msg: String? = null) {

app/src/main/java/com/futo/platformplayer/helpers/VideoHelper.kt

@@ -19,6 +19,8 @@ import com.futo.platformplayer.api.media.models.streams.sources.IHLSManifestSour
 import com.futo.platformplayer.api.media.models.streams.sources.IVideoSource
 import com.futo.platformplayer.api.media.models.streams.sources.IVideoUrlSource
 import com.futo.platformplayer.api.media.models.streams.sources.IWidevineSource
+import com.futo.platformplayer.api.media.models.subtitles.ISubtitleSource
+import com.futo.platformplayer.api.media.models.video.IPlatformVideo
 import com.futo.platformplayer.api.media.models.video.IPlatformVideoDetails
 import com.futo.platformplayer.api.media.platforms.js.models.sources.JSAudioUrlRangeSource
 import com.futo.platformplayer.api.media.platforms.js.models.sources.JSDashManifestRawAudioSource
@@ -134,6 +136,62 @@ class VideoHelper {
             return bestSource;
         }
 
+        fun selectBestSubtitleSource(sources: Iterable<ISubtitleSource>, preferredLanguage: String?): ISubtitleSource? {
+            if (preferredLanguage.isNullOrBlank()) return null
+
+            val prefTag = normalizeTag(preferredLanguage)
+            val prefPrimary = primarySubtag(prefTag) ?: return null
+
+            var best: ISubtitleSource? = null
+            var bestKey: Quad<Int, Int, String, String>? = null
+
+            for (src in sources) {
+                val raw = src.language ?: continue
+                val tag = normalizeTag(raw)
+                val primary = primarySubtag(tag) ?: continue
+
+                val score = when {
+                    tag.equals(prefTag, ignoreCase = true) -> 0
+                    primary.equals(prefPrimary, ignoreCase = true) && findRegion(tag) == null -> 1
+                    primary.equals(prefPrimary, ignoreCase = true) -> 2
+                    else -> 3
+                }
+                if (score >= 3) continue
+
+                val key = Quad(score, src.name.length, tag.lowercase(), src.name)
+                if (bestKey == null || key < bestKey!!) {
+                    bestKey = key
+                    best = src
+                }
+            }
+            return best
+        }
+
+        private fun normalizeTag(tag: String): String = tag.trim().replace('_', '-')
+        private fun primarySubtag(tag: String): String? = tag.split('-').firstOrNull { it.isNotBlank() }?.lowercase()
+
+        private fun findRegion(tag: String): String? {
+            val parts = tag.split('-').drop(1) // skip primary language
+            for (p in parts) {
+                val isAlpha2 = p.length == 2 && p[0].isLetter() && p[1].isLetter()
+                val isNumeric3 = p.length == 3 && p.all { it.isDigit() }
+                if (isAlpha2 || isNumeric3) return p.uppercase()
+            }
+            return null
+        }
+
+        private data class Quad<A : Comparable<A>, B : Comparable<B>, C : Comparable<C>, D : Comparable<D>>(
+            val a: A, val b: B, val c: C, val d: D
+        ) : Comparable<Quad<A, B, C, D>> {
+            override fun compareTo(other: Quad<A, B, C, D>): Int =
+                when {
+                    a != other.a -> a.compareTo(other.a)
+                    b != other.b -> b.compareTo(other.b)
+                    c != other.c -> c.compareTo(other.c)
+                    else -> d.compareTo(other.d)
+                }
+        }
+
         @OptIn(UnstableApi::class)
         fun convertItagSourceToChunkedDashSource(videoSource: JSVideoUrlRangeSource) : Pair<MediaSource, String> {
             val urlToUse = videoSource.getVideoUrl();

app/src/main/java/com/futo/platformplayer/states/StateDownloads.kt

@@ -439,7 +439,7 @@ class StateDownloads {
         } else {
             throw NotImplementedError("Unsuported scheme");
         }
-        return if (subtitles != null) SubtitleRawSource(subtitle.name, subtitle.format, subtitles!!) else null;
+        return if (subtitles != null) SubtitleRawSource(subtitle.name, subtitle.language, subtitle.format, subtitles!!) else null;
     }
 
     fun cleanupDownloads(): Pair<Int, Long> {

app/src/main/java/com/futo/platformplayer/views/video/FutoVideoPlayerBase.kt

@@ -914,6 +914,10 @@ abstract class FutoVideoPlayerBase : RelativeLayout {
         return VideoHelper.selectBestAudioSource(video.video, PREFERED_AUDIO_CONTAINERS, preferredLanguage);
     }
 
+    fun getPreferredSubtitleSource(video: IPlatformVideoDetails, preferredLanguage: String?): ISubtitleSource? {
+        return VideoHelper.selectBestSubtitleSource(video.subtitles, preferredLanguage);
+    }
+
     @OptIn(UnstableApi::class)
     private fun loadSelectedSources(play: Boolean, resume: Boolean): Boolean {
         val sourceVideo = if(!isAudioMode || _lastAudioMediaSource == null) _lastVideoMediaSource else null;

app/src/main/res/values/strings.xml

@@ -505,6 +505,8 @@
     <string name="preferred_preview_quality">Preferred Preview Quality</string>
     <string name="preferred_preview_quality_description">Default quality while previewing a video in a feed</string>
     <string name="primary_language">Primary Language</string>
+    <string name="sticky_subtitles">Persist Subtitles</string>
+    <string name="sticky_subtitles_description">Once a subtitle language is selected, search for a best match once a new video is played</string>
     <string name="prefer_original_audio">Prefer Original Audio</string>
     <string name="prefer_original_audio_description">Use original audio instead of preferred language when it is known</string>
     <string name="default_comment_section">Default Comment Section</string>