Stabilize HLS playback timestamps

core/data/src/main/java/hu/bbara/purefin/core/data/client/AndroidDeviceProfile.kt

@@ -68,6 +68,8 @@ object AndroidDeviceProfile {
         videoCodecs: List<String>,
         maxAudioChannels: Int
     ): DeviceProfile {
+        val hlsOptions = HlsPlaybackStability.conservativeHlsOptions
+
         return DeviceProfile(
             name = "Android Media3",
             maxStaticBitrate = 100_000_000,
@@ -94,8 +96,10 @@ object AndroidDeviceProfile {
                     protocol = MediaStreamProtocol.HLS,
                     context = EncodingContext.STREAMING,
                     maxAudioChannels = maxAudioChannels.toString(),
-                    minSegments = 2,
+                    minSegments = hlsOptions.minSegments,
-                    breakOnNonKeyFrames = true,
+                    segmentLength = hlsOptions.segmentLengthSeconds,
+                    breakOnNonKeyFrames = hlsOptions.breakOnNonKeyFrames,
+                    copyTimestamps = hlsOptions.copyTimestamps,
                     conditions = emptyList()
                 )
             ),

core/data/src/main/java/hu/bbara/purefin/core/data/client/HlsPlaybackStability.kt

@@ -0,0 +1,17 @@
+package hu.bbara.purefin.core.data.client
+
+internal data class HlsStabilityOptions(
+    val segmentLengthSeconds: Int,
+    val minSegments: Int,
+    val breakOnNonKeyFrames: Boolean,
+    val copyTimestamps: Boolean
+)
+
+internal object HlsPlaybackStability {
+    val conservativeHlsOptions = HlsStabilityOptions(
+        segmentLengthSeconds = 6,
+        minSegments = 3,
+        breakOnNonKeyFrames = false,
+        copyTimestamps = true
+    )
+}

core/data/src/main/java/hu/bbara/purefin/core/data/client/JellyfinApiClient.kt

@@ -50,6 +50,14 @@ class JellyfinApiClient @Inject constructor(
     companion object {
         private const val TAG = "JellyfinApiClient"
         private const val MAX_STREAMING_BITRATE = 100_000_000
+
+        internal fun streamingHlsOptionsFor(
+            urlStrategy: PlaybackSourcePlanner.UrlStrategy
+        ): HlsStabilityOptions? = when (urlStrategy) {
+            PlaybackSourcePlanner.UrlStrategy.DIRECT_PLAY -> null
+            PlaybackSourcePlanner.UrlStrategy.DIRECT_STREAM,
+            PlaybackSourcePlanner.UrlStrategy.TRANSCODE -> HlsPlaybackStability.conservativeHlsOptions
+        }
     }
 
     private val jellyfin = createJellyfin {
@@ -405,6 +413,11 @@ class JellyfinApiClient @Inject constructor(
         }
 
         val capabilitySnapshot = AndroidDeviceProfile.getSnapshot(applicationContext)
+        Log.d(
+            TAG,
+            "Playback request for $mediaId (forceTranscode=$forceTranscode) maxAudioChannels=${capabilitySnapshot.maxAudioChannels}, " +
+                "hlsOptions=${HlsPlaybackStability.conservativeHlsOptions}"
+        )
         val response = api.mediaInfoApi.getPostedPlaybackInfo(
             mediaId,
             PlaybackInfoDto(
@@ -467,6 +480,14 @@ class JellyfinApiClient @Inject constructor(
         playSessionId: String?,
         maxAudioChannels: Int
     ): String {
+        val hlsOptions = streamingHlsOptionsFor(PlaybackSourcePlanner.UrlStrategy.DIRECT_STREAM)
+            ?: error("Direct stream requests must use HLS stability options.")
+
+        Log.d(
+            TAG,
+            "Stream URL request for $mediaId strategy=DIRECT_STREAM container=${mediaSource.transcodingContainer ?: mediaSource.container}, " +
+                "hlsOptions=$hlsOptions"
+        )
         return api.videosApi.getVideoStreamUrl(
             itemId = mediaId,
             static = false,
@@ -474,9 +495,13 @@ class JellyfinApiClient @Inject constructor(
             playSessionId = playSessionId,
             liveStreamId = mediaSource.liveStreamId,
             container = mediaSource.transcodingContainer ?: mediaSource.container,
+            segmentLength = hlsOptions.segmentLengthSeconds,
+            minSegments = hlsOptions.minSegments,
             enableAutoStreamCopy = true,
             allowVideoStreamCopy = true,
             allowAudioStreamCopy = true,
+            breakOnNonKeyFrames = hlsOptions.breakOnNonKeyFrames,
+            copyTimestamps = hlsOptions.copyTimestamps,
             maxAudioChannels = maxAudioChannels
         )
     }
@@ -487,7 +512,15 @@ class JellyfinApiClient @Inject constructor(
         playSessionId: String?,
         maxAudioChannels: Int
     ): String? {
+        val hlsOptions = streamingHlsOptionsFor(PlaybackSourcePlanner.UrlStrategy.TRANSCODE)
+            ?: error("Transcode requests must use HLS stability options.")
+
         mediaSource.transcodingUrl?.takeIf { it.isNotBlank() }?.let { transcodingUrl ->
+            Log.d(
+                TAG,
+                "Using server transcodingUrl for $mediaId strategy=TRANSCODE container=${mediaSource.transcodingContainer ?: mediaSource.container}, " +
+                    "hlsOptions=$hlsOptions"
+            )
             if (transcodingUrl.startsWith("http", ignoreCase = true)) {
                 return transcodingUrl
             }
@@ -495,6 +528,11 @@ class JellyfinApiClient @Inject constructor(
             return "$baseUrl$transcodingUrl"
         }
 
+        Log.d(
+            TAG,
+            "Stream URL request for $mediaId strategy=TRANSCODE container=${mediaSource.transcodingContainer ?: mediaSource.container ?: "mp4"}, " +
+                "hlsOptions=$hlsOptions"
+        )
         return api.videosApi.getVideoStreamUrl(
             itemId = mediaId,
             static = false,
@@ -502,9 +540,13 @@ class JellyfinApiClient @Inject constructor(
             playSessionId = playSessionId,
             liveStreamId = mediaSource.liveStreamId,
             container = mediaSource.transcodingContainer ?: mediaSource.container ?: "mp4",
+            segmentLength = hlsOptions.segmentLengthSeconds,
+            minSegments = hlsOptions.minSegments,
             enableAutoStreamCopy = false,
             allowVideoStreamCopy = false,
             allowAudioStreamCopy = false,
+            breakOnNonKeyFrames = hlsOptions.breakOnNonKeyFrames,
+            copyTimestamps = hlsOptions.copyTimestamps,
             maxAudioChannels = maxAudioChannels
         )
     }

core/data/src/test/java/hu/bbara/purefin/core/data/client/AndroidDeviceProfileTest.kt

@@ -4,6 +4,7 @@ import org.jellyfin.sdk.model.api.DlnaProfileType
 import org.jellyfin.sdk.model.api.EncodingContext
 import org.jellyfin.sdk.model.api.MediaStreamProtocol
 import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
 import org.junit.Assert.assertTrue
 import org.junit.Test
 
@@ -25,7 +26,9 @@ class AndroidDeviceProfileTest {
         assertEquals(MediaStreamProtocol.HLS, transcodingProfile.protocol)
         assertEquals(EncodingContext.STREAMING, transcodingProfile.context)
         assertEquals("6", transcodingProfile.maxAudioChannels)
-        assertEquals(2, transcodingProfile.minSegments)
+        assertEquals(3, transcodingProfile.minSegments)
-        assertTrue(transcodingProfile.breakOnNonKeyFrames)
+        assertEquals(6, transcodingProfile.segmentLength)
+        assertFalse(transcodingProfile.breakOnNonKeyFrames)
+        assertTrue(transcodingProfile.copyTimestamps)
     }
 }

core/data/src/test/java/hu/bbara/purefin/core/data/client/JellyfinApiClientTest.kt

@@ -0,0 +1,29 @@
+package hu.bbara.purefin.core.data.client
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNull
+import org.junit.Test
+
+class JellyfinApiClientTest {
+    @Test
+    fun `direct play requests do not apply HLS stability options`() {
+        val options = JellyfinApiClient.streamingHlsOptionsFor(PlaybackSourcePlanner.UrlStrategy.DIRECT_PLAY)
+
+        assertNull(options)
+    }
+
+    @Test
+    fun `direct stream requests use conservative HLS stability options`() {
+        val options = JellyfinApiClient.streamingHlsOptionsFor(PlaybackSourcePlanner.UrlStrategy.DIRECT_STREAM)
+
+        assertEquals(HlsPlaybackStability.conservativeHlsOptions, options)
+    }
+
+    @Test
+    fun `transcode requests use the same HLS stability options as direct stream`() {
+        val directStreamOptions = JellyfinApiClient.streamingHlsOptionsFor(PlaybackSourcePlanner.UrlStrategy.DIRECT_STREAM)
+        val transcodeOptions = JellyfinApiClient.streamingHlsOptionsFor(PlaybackSourcePlanner.UrlStrategy.TRANSCODE)
+
+        assertEquals(directStreamOptions, transcodeOptions)
+    }
+}