Block HLS playlist requests at part level

Issue: #5011
PiperOrigin-RevId: 340625816

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/DefaultHlsPlaylistTracker.java

@@ -30,6 +30,7 @@ import com.google.android.exoplayer2.source.MediaLoadData;
 import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
 import com.google.android.exoplayer2.source.hls.HlsDataSourceFactory;
 import com.google.android.exoplayer2.source.hls.playlist.HlsMasterPlaylist.Variant;
+import com.google.android.exoplayer2.source.hls.playlist.HlsMediaPlaylist.Part;
 import com.google.android.exoplayer2.source.hls.playlist.HlsMediaPlaylist.Segment;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.HttpDataSource;
@@ -40,6 +41,7 @@ import com.google.android.exoplayer2.upstream.Loader.LoadErrorAction;
 import com.google.android.exoplayer2.upstream.ParsingLoadable;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Util;
+import com.google.common.collect.Iterables;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -465,6 +467,7 @@ public final class DefaultHlsPlaylistTracker
   private final class MediaPlaylistBundle implements Loader.Callback<ParsingLoadable<HlsPlaylist>> {
 
     private static final String BLOCK_MSN_PARAM = "_HLS_msn";
+    private static final String BLOCK_PART_PARAM = "_HLS_part";
     private static final String SKIP_PARAM = "_HLS_skip";
 
     private final Uri playlistUrl;
@@ -729,16 +732,25 @@ public final class DefaultHlsPlaylistTracker
         return playlistUrl;
       }
       Uri.Builder uriBuilder = playlistUrl.buildUpon();
-      if (playlistSnapshot.serverControl.skipUntilUs != C.TIME_UNSET) {
-        uriBuilder.appendQueryParameter(
-            SKIP_PARAM, playlistSnapshot.serverControl.canSkipDateRanges ? "v2" : "YES");
-      }
       if (playlistSnapshot.serverControl.canBlockReload) {
-        long reloadMediaSequence =
+        long targetMediaSequence =
             playlistSnapshot.mediaSequence
                 + playlistSnapshot.segments.size()
                 + playlistSnapshot.skippedSegmentCount;
-        uriBuilder.appendQueryParameter(BLOCK_MSN_PARAM, String.valueOf(reloadMediaSequence));
+        uriBuilder.appendQueryParameter(BLOCK_MSN_PARAM, String.valueOf(targetMediaSequence));
+        if (playlistSnapshot.partTargetDurationUs != C.TIME_UNSET) {
+          List<Part> trailingParts = playlistSnapshot.trailingParts;
+          int targetPartIndex = trailingParts.size();
+          if (!trailingParts.isEmpty() && Iterables.getLast(trailingParts).isPreload) {
+            // Ignore the preload part.
+            targetPartIndex--;
+          }
+          uriBuilder.appendQueryParameter(BLOCK_PART_PARAM, String.valueOf(targetPartIndex));
+        }
+      }
+      if (playlistSnapshot.serverControl.skipUntilUs != C.TIME_UNSET) {
+        uriBuilder.appendQueryParameter(
+            SKIP_PARAM, playlistSnapshot.serverControl.canSkipDateRanges ? "v2" : "YES");
       }
       return uriBuilder.build();
     }

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylist.java

@@ -176,6 +176,8 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
 
     /** Whether the part is independent. */
     public final boolean isIndependent;
+    /** Whether the part is a preloading part. */
+    public final boolean isPreload;
 
     /**
      * Creates an instance.
@@ -192,6 +194,7 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
      * @param byteRangeLength See {@link #byteRangeLength}.
      * @param hasGapTag See {@link #hasGapTag}.
      * @param isIndependent See {@link #isIndependent}.
+     * @param isPreload See {@link #isPreload}.
      */
     public Part(
         String url,
@@ -205,7 +208,8 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
         long byteRangeOffset,
         long byteRangeLength,
         boolean hasGapTag,
-        boolean isIndependent) {
+        boolean isIndependent,
+        boolean isPreload) {
       super(
           url,
           initializationSegment,
@@ -219,6 +223,7 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
           byteRangeLength,
           hasGapTag);
       this.isIndependent = isIndependent;
+      this.isPreload = isPreload;
     }
   }
 
@@ -502,8 +507,13 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
     // The media sequences are equal.
     int segmentCount = segments.size() + skippedSegmentCount;
     int otherSegmentCount = other.segments.size() + other.skippedSegmentCount;
-    return segmentCount > otherSegmentCount
-        || (segmentCount == otherSegmentCount && hasEndTag && !other.hasEndTag);
+    if (segmentCount != otherSegmentCount) {
+      return segmentCount > otherSegmentCount;
+    }
+    int partCount = trailingParts.size();
+    int otherPartCount = other.trailingParts.size();
+    return partCount > otherPartCount
+        || (partCount == otherPartCount && hasEndTag && !other.hasEndTag);
   }
 
   /**

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistParser.java

@@ -824,7 +824,8 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
                 byteRangeStart,
                 byteRangeLength,
                 /* hasGapTag= */ false,
-                /* isIndependent= */ false);
+                /* isIndependent= */ false,
+                /* isPreload= */ true);
       } else if (line.startsWith(TAG_PART)) {
         @Nullable
         String segmentEncryptionIV =
@@ -869,7 +870,8 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
                 partByteRangeOffset,
                 partByteRangeLength,
                 isGap,
-                isIndependent));
+                isIndependent,
+                /* isPreload= */ false));
         partStartTimeUs += partDurationUs;
         if (partByteRangeLength != C.LENGTH_UNSET) {
           partByteRangeOffset += partByteRangeLength;

library/hls/src/test/java/com/google/android/exoplayer2/source/hls/playlist/DefaultHlsPlaylistTrackerTest.java

@@ -64,6 +64,21 @@ public class DefaultHlsPlaylistTrackerTest {
       "media/m3u8/live_low_latency_media_can_block_reload";
   private static final String SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_NEXT =
       "media/m3u8/live_low_latency_media_can_block_reload_next";
+  private static final String SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY =
+      "media/m3u8/live_low_latency_media_can_block_reload_low_latency";
+  private static final String SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_NEXT =
+      "media/m3u8/live_low_latency_media_can_block_reload_low_latency_next";
+  private static final String SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT =
+      "media/m3u8/live_low_latency_media_can_block_reload_low_latency_full_segment";
+  private static final String
+      SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT_NEXT =
+          "media/m3u8/live_low_latency_media_can_block_reload_low_latency_full_segment_next";
+  private static final String
+      SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT_PRELOAD =
+          "media/m3u8/live_low_latency_media_can_block_reload_low_latency_full_segment_preload";
+  private static final String
+      SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT_PRELOAD_NEXT =
+          "media/m3u8/live_low_latency_media_can_block_reload_low_latency_full_segment_preload_next";
   private static final String SAMPLE_M3U8_LIVE_MEDIA_CAN_SKIP_UNTIL_AND_BLOCK_RELOAD =
       "media/m3u8/live_low_latency_media_can_skip_until_and_block_reload";
   private static final String SAMPLE_M3U8_LIVE_MEDIA_CAN_SKIP_UNTIL_AND_BLOCK_RELOAD_NEXT =
@@ -256,6 +271,96 @@ public class DefaultHlsPlaylistTrackerTest {
   }
 
   @Test
+  public void
+      start_playlistCanBlockReloadLowLatency_requestBlockingReloadWithCorrectMediaSequenceAndPart()
+          throws IOException, TimeoutException, InterruptedException {
+    List<HttpUrl> httpUrls =
+        enqueueWebServerResponses(
+            new String[] {
+              "/master.m3u8",
+              "/media0/playlist.m3u8",
+              "/media0/playlist.m3u8?_HLS_msn=14&_HLS_part=1"
+            },
+            getMockResponse(SAMPLE_M3U8_LIVE_MASTER),
+            getMockResponse(SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY),
+            getMockResponse(SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_NEXT));
+
+    List<HlsMediaPlaylist> mediaPlaylists =
+        runPlaylistTrackerAndCollectMediaPlaylists(
+            new DefaultHttpDataSourceFactory(),
+            Uri.parse(mockWebServer.url("/master.m3u8").toString()),
+            /* awaitedMediaPlaylistCount= */ 2);
+
+    assertRequestUrlsCalled(httpUrls);
+    assertThat(mediaPlaylists.get(0).mediaSequence).isEqualTo(10);
+    assertThat(mediaPlaylists.get(0).segments).hasSize(4);
+    assertThat(mediaPlaylists.get(0).trailingParts).hasSize(2);
+    assertThat(mediaPlaylists.get(1).mediaSequence).isEqualTo(10);
+    assertThat(mediaPlaylists.get(1).segments).hasSize(4);
+    assertThat(mediaPlaylists.get(1).trailingParts).hasSize(3);
+  }
+
+  @Test
+  public void start_playlistCanBlockReloadLowLatencyFullSegment_correctMsnAndPartParams()
+      throws IOException, TimeoutException, InterruptedException {
+    List<HttpUrl> httpUrls =
+        enqueueWebServerResponses(
+            new String[] {
+              "/master.m3u8",
+              "/media0/playlist.m3u8",
+              "/media0/playlist.m3u8?_HLS_msn=14&_HLS_part=0"
+            },
+            getMockResponse(SAMPLE_M3U8_LIVE_MASTER),
+            getMockResponse(SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT),
+            getMockResponse(SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT_NEXT));
+
+    List<HlsMediaPlaylist> mediaPlaylists =
+        runPlaylistTrackerAndCollectMediaPlaylists(
+            new DefaultHttpDataSourceFactory(),
+            Uri.parse(mockWebServer.url("/master.m3u8").toString()),
+            /* awaitedMediaPlaylistCount= */ 2);
+
+    assertRequestUrlsCalled(httpUrls);
+    assertThat(mediaPlaylists.get(0).mediaSequence).isEqualTo(10);
+    assertThat(mediaPlaylists.get(0).segments).hasSize(4);
+    assertThat(mediaPlaylists.get(0).trailingParts).isEmpty();
+    assertThat(mediaPlaylists.get(1).mediaSequence).isEqualTo(10);
+    assertThat(mediaPlaylists.get(1).segments).hasSize(4);
+    assertThat(mediaPlaylists.get(1).trailingParts).hasSize(1);
+  }
+
+  @Test
+  public void start_playlistCanBlockReloadLowLatencyFullSegmentWithPreloadPart_ignoresPreloadPart()
+      throws IOException, TimeoutException, InterruptedException {
+    List<HttpUrl> httpUrls =
+        enqueueWebServerResponses(
+            new String[] {
+              "/master.m3u8",
+              "/media0/playlist.m3u8",
+              "/media0/playlist.m3u8?_HLS_msn=14&_HLS_part=0"
+            },
+            getMockResponse(SAMPLE_M3U8_LIVE_MASTER),
+            getMockResponse(
+                SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT_PRELOAD),
+            getMockResponse(
+                SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT_PRELOAD_NEXT));
+
+    List<HlsMediaPlaylist> mediaPlaylists =
+        runPlaylistTrackerAndCollectMediaPlaylists(
+            new DefaultHttpDataSourceFactory(),
+            Uri.parse(mockWebServer.url("/master.m3u8").toString()),
+            /* awaitedMediaPlaylistCount= */ 2);
+
+    assertRequestUrlsCalled(httpUrls);
+    assertThat(mediaPlaylists.get(0).mediaSequence).isEqualTo(10);
+    assertThat(mediaPlaylists.get(0).segments).hasSize(4);
+    assertThat(mediaPlaylists.get(0).trailingParts).hasSize(1);
+    assertThat(mediaPlaylists.get(1).mediaSequence).isEqualTo(10);
+    assertThat(mediaPlaylists.get(1).segments).hasSize(4);
+    assertThat(mediaPlaylists.get(1).trailingParts).hasSize(2);
+  }
+
+  @Test
   public void start_httpBadRequest_forcesFullNonBlockingPlaylistRequest()
       throws IOException, TimeoutException, InterruptedException {
     List<HttpUrl> httpUrls =
@@ -263,9 +368,9 @@ public class DefaultHlsPlaylistTrackerTest {
             new String[] {
               "/master.m3u8",
               "/media0/playlist.m3u8",
-              "/media0/playlist.m3u8?_HLS_skip=YES&_HLS_msn=16",
+              "/media0/playlist.m3u8?_HLS_msn=16&_HLS_skip=YES",
               "/media0/playlist.m3u8",
-              "/media0/playlist.m3u8?_HLS_skip=YES&_HLS_msn=17"
+              "/media0/playlist.m3u8?_HLS_msn=17&_HLS_skip=YES"
             },
             getMockResponse(SAMPLE_M3U8_LIVE_MASTER),
             getMockResponse(SAMPLE_M3U8_LIVE_MEDIA_CAN_SKIP_UNTIL_AND_BLOCK_RELOAD),

library/hls/src/test/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylistParserTest.java

@@ -354,6 +354,7 @@ public class HlsMediaPlaylistParserTest {
     assertThat(firstPart.durationUs).isEqualTo(2_000_000);
     assertThat(firstPart.relativeStartTimeUs).isEqualTo(playlist.segments.get(0).durationUs);
     assertThat(firstPart.isIndependent).isTrue();
+    assertThat(firstPart.isPreload).isFalse();
     assertThat(firstPart.hasGapTag).isTrue();
     assertThat(firstPart.url).isEqualTo("part267.1.ts");
     HlsMediaPlaylist.Part secondPart = playlist.segments.get(1).parts.get(1);
@@ -518,6 +519,7 @@ public class HlsMediaPlaylistParserTest {
     assertThat(preloadPart.byteRangeOffset).isEqualTo(1234);
     assertThat(preloadPart.initializationSegment.url).isEqualTo("map.mp4");
     assertThat(preloadPart.encryptionIV).isEqualTo("0x410C8AC18AA42EFA18B5155484F5FC34");
+    assertThat(preloadPart.isPreload).isTrue();
   }
 
   @Test
@@ -539,6 +541,7 @@ public class HlsMediaPlaylistParserTest {
 
     assertThat(playlist.trailingParts).hasSize(2);
     assertThat(playlist.trailingParts.get(1).url).isEqualTo("filePart267.2.ts");
+    assertThat(playlist.trailingParts.get(1).isPreload).isTrue();
   }
 
   @Test

testdata/src/test/assets/media/m3u8/live_low_latency_media_can_block_reload_low_latency

+#EXTM3U
+#EXT-X-SERVER-CONTROL:CAN-BLOCK-RELOAD=YES
+#EXT-X-TARGETDURATION:4
+#EXT-X-PART-INF:PART-TARGET=1.000000
+#EXT-X-VERSION:3
+#EXT-X-MEDIA-SEQUENCE:10
+#EXTINF:4.00000,
+fileSequence10.ts
+#EXTINF:4.00000,
+fileSequence11.ts
+#EXTINF:4.00000,
+fileSequence12.ts
+#EXTINF:4.00000,
+fileSequence13.ts
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence14.0.ts"
+#EXT-X-PRELOAD-HINT:TYPE=PART,URI="fileSequence14.1.ts"

testdata/src/test/assets/media/m3u8/live_low_latency_media_can_block_reload_low_latency_full_segment

+#EXTM3U
+#EXT-X-SERVER-CONTROL:CAN-BLOCK-RELOAD=YES
+#EXT-X-TARGETDURATION:4
+#EXT-X-PART-INF:PART-TARGET=1.000000
+#EXT-X-VERSION:3
+#EXT-X-MEDIA-SEQUENCE:10
+#EXTINF:4.00000,
+fileSequence10.ts
+#EXTINF:4.00000,
+fileSequence11.ts
+#EXTINF:4.00000,
+fileSequence12.ts
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.0.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.1.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.2.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.3.ts"
+#EXTINF:4.00000,
+fileSequence13.ts

testdata/src/test/assets/media/m3u8/live_low_latency_media_can_block_reload_low_latency_full_segment_next

+#EXTM3U
+#EXT-X-SERVER-CONTROL:CAN-BLOCK-RELOAD=YES
+#EXT-X-TARGETDURATION:4
+#EXT-X-PART-INF:PART-TARGET=1.000000
+#EXT-X-VERSION:3
+#EXT-X-MEDIA-SEQUENCE:10
+#EXTINF:4.00000,
+fileSequence10.ts
+#EXTINF:4.00000,
+fileSequence11.ts
+#EXTINF:4.00000,
+fileSequence12.ts
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.0.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.1.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.2.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.3.ts"
+#EXTINF:4.00000,
+fileSequence13.ts
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence14.0.ts"

testdata/src/test/assets/media/m3u8/live_low_latency_media_can_block_reload_low_latency_full_segment_preload

+#EXTM3U
+#EXT-X-SERVER-CONTROL:CAN-BLOCK-RELOAD=YES
+#EXT-X-TARGETDURATION:4
+#EXT-X-PART-INF:PART-TARGET=1.000000
+#EXT-X-VERSION:3
+#EXT-X-MEDIA-SEQUENCE:10
+#EXTINF:4.00000,
+fileSequence10.ts
+#EXTINF:4.00000,
+fileSequence11.ts
+#EXTINF:4.00000,
+fileSequence12.ts
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.0.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.1.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.2.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.3.ts"
+#EXTINF:4.00000,
+fileSequence13.ts
+#EXT-X-PRELOAD-HINT:TYPE=PART,URI="fileSequence14.0.ts"

testdata/src/test/assets/media/m3u8/live_low_latency_media_can_block_reload_low_latency_full_segment_preload_next

+#EXTM3U
+#EXT-X-SERVER-CONTROL:CAN-BLOCK-RELOAD=YES
+#EXT-X-TARGETDURATION:4
+#EXT-X-PART-INF:PART-TARGET=1.000000
+#EXT-X-VERSION:3
+#EXT-X-MEDIA-SEQUENCE:10
+#EXTINF:4.00000,
+fileSequence10.ts
+#EXTINF:4.00000,
+fileSequence11.ts
+#EXTINF:4.00000,
+fileSequence12.ts
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.0.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.1.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.2.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.3.ts"
+#EXTINF:4.00000,
+fileSequence13.ts
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence14.0.ts"
+#EXT-X-PRELOAD-HINT:TYPE=PART,URI="fileSequence14.1.ts"

testdata/src/test/assets/media/m3u8/live_low_latency_media_can_block_reload_low_latency_next

+#EXTM3U
+#EXT-X-SERVER-CONTROL:CAN-BLOCK-RELOAD=YES
+#EXT-X-TARGETDURATION:4
+#EXT-X-PART-INF:PART-TARGET=1.000000
+#EXT-X-VERSION:3
+#EXT-X-MEDIA-SEQUENCE:10
+#EXTINF:4.00000,
+fileSequence10.ts
+#EXTINF:4.00000,
+fileSequence11.ts
+#EXTINF:4.00000,
+fileSequence12.ts
+#EXTINF:4.00000,
+fileSequence13.ts
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence14.0.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence14.1.ts"
+#EXT-X-PRELOAD-HINT:TYPE=PART,URI="fileSequence14.2.ts"