Use identical cache keys for downloading and playing DASH segments

Issue: #9370
PiperOrigin-RevId: 395429794

RELEASENOTES.md

@@ -23,6 +23,9 @@
         thrown from `Requirements.isInternetConnectivityValidated` on devices
         running Android 11
         ([#9002](https://github.com/google/ExoPlayer/issues/9002)).
+*   DASH:
+    *   Use identical cache keys for downloading and playing DASH segments
+        ([#9370](https://github.com/google/ExoPlayer/issues/9370)).
 *   RTSP:
     *   Handle when additional spaces are in SDP's RTPMAP atrribute
         ([#9379](https://github.com/google/ExoPlayer/issues/9379)).

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashUtil.java

@@ -46,20 +46,20 @@ public final class DashUtil {
   /**
    * Builds a {@link DataSpec} for a given {@link RangedUri} belonging to {@link Representation}.
    *
+   * @param representation The {@link Representation} to which the request belongs.
    * @param baseUrl The base url with which to resolve the request URI.
    * @param requestUri The {@link RangedUri} of the data to request.
-   * @param cacheKey An optional cache key.
    * @param flags Flags to be set on the returned {@link DataSpec}. See {@link
    *     DataSpec.Builder#setFlags(int)}.
    * @return The {@link DataSpec}.
    */
   public static DataSpec buildDataSpec(
-      String baseUrl, RangedUri requestUri, @Nullable String cacheKey, int flags) {
+      Representation representation, String baseUrl, RangedUri requestUri, int flags) {
     return new DataSpec.Builder()
         .setUri(requestUri.resolveUri(baseUrl))
         .setPosition(requestUri.start)
         .setLength(requestUri.length)
-        .setKey(cacheKey)
+        .setKey(resolveCacheKey(representation, requestUri))
         .setFlags(flags)
         .build();
   }
@@ -77,8 +77,7 @@ public final class DashUtil {
    */
   public static DataSpec buildDataSpec(
       Representation representation, RangedUri requestUri, int flags) {
-    return buildDataSpec(
-        representation.baseUrls.get(0).url, requestUri, representation.getCacheKey(), flags);
+    return buildDataSpec(representation, representation.baseUrls.get(0).url, requestUri, flags);
   }
 
   /**
@@ -289,9 +288,9 @@ public final class DashUtil {
       throws IOException {
     DataSpec dataSpec =
         DashUtil.buildDataSpec(
+            representation,
             representation.baseUrls.get(baseUrlIndex).url,
             requestUri,
-            representation.getCacheKey(),
             /* flags= */ 0);
     InitializationChunk initializationChunk =
         new InitializationChunk(
@@ -304,6 +303,21 @@ public final class DashUtil {
     initializationChunk.load();
   }
 
+  /**
+   * Resolves the cache key to be used when requesting the given ranged URI for the given {@link
+   * Representation}.
+   *
+   * @param representation The {@link Representation} to which the URI belongs to.
+   * @param rangedUri The URI for which to resolve the cache key.
+   * @return The cache key.
+   */
+  public static String resolveCacheKey(Representation representation, RangedUri rangedUri) {
+    @Nullable String cacheKey = representation.getCacheKey();
+    return cacheKey != null
+        ? cacheKey
+        : rangedUri.resolveUri(representation.baseUrls.get(0).url).toString();
+  }
+
   private static ChunkExtractor newChunkExtractor(int trackType, Format format) {
     String mimeType = format.containerMimeType;
     boolean isWebm =

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DefaultDashChunkSource.java

@@ -628,10 +628,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
     }
     DataSpec dataSpec =
         DashUtil.buildDataSpec(
-            representationHolder.selectedBaseUrl.url,
-            requestUri,
-            representation.getCacheKey(),
-            /* flags= */ 0);
+            representation, representationHolder.selectedBaseUrl.url, requestUri, /* flags= */ 0);
     return new InitializationChunk(
         dataSource,
         dataSpec,
@@ -664,10 +661,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
               : DataSpec.FLAG_MIGHT_NOT_USE_FULL_NETWORK_SPEED;
       DataSpec dataSpec =
           DashUtil.buildDataSpec(
-              representationHolder.selectedBaseUrl.url,
-              segmentUri,
-              representation.getCacheKey(),
-              flags);
+              representation, representationHolder.selectedBaseUrl.url, segmentUri, flags);
       return new SingleSampleMediaChunk(
           dataSource,
           dataSpec,
@@ -706,10 +700,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
               : DataSpec.FLAG_MIGHT_NOT_USE_FULL_NETWORK_SPEED;
       DataSpec dataSpec =
           DashUtil.buildDataSpec(
-              representationHolder.selectedBaseUrl.url,
-              segmentUri,
-              representation.getCacheKey(),
-              flags);
+              representation, representationHolder.selectedBaseUrl.url, segmentUri, flags);
       long sampleOffsetUs = -representation.presentationTimeOffsetUs;
       return new ContainerMediaChunk(
           dataSource,
@@ -765,9 +756,9 @@ public class DefaultDashChunkSource implements DashChunkSource {
               ? 0
               : DataSpec.FLAG_MIGHT_NOT_USE_FULL_NETWORK_SPEED;
       return DashUtil.buildDataSpec(
+          representationHolder.representation,
           representationHolder.selectedBaseUrl.url,
           segmentUri,
-          representationHolder.representation.getCacheKey(),
           flags);
     }
 

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/offline/DashDownloader.java

@@ -15,12 +15,15 @@
  */
 package com.google.android.exoplayer2.source.dash.offline;
 
+import static com.google.android.exoplayer2.util.Util.castNonNull;
+
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.MediaItem;
 import com.google.android.exoplayer2.extractor.ChunkIndex;
 import com.google.android.exoplayer2.offline.DownloadException;
 import com.google.android.exoplayer2.offline.SegmentDownloader;
+import com.google.android.exoplayer2.source.dash.BaseUrlExclusionList;
 import com.google.android.exoplayer2.source.dash.DashSegmentIndex;
 import com.google.android.exoplayer2.source.dash.DashUtil;
 import com.google.android.exoplayer2.source.dash.DashWrappingSegmentIndex;
@@ -70,6 +73,8 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
  */
 public final class DashDownloader extends SegmentDownloader<DashManifest> {
 
+  private final BaseUrlExclusionList baseUrlExclusionList;
+
   /**
    * Creates a new instance.
    *
@@ -113,6 +118,7 @@ public final class DashDownloader extends SegmentDownloader<DashManifest> {
       CacheDataSource.Factory cacheDataSourceFactory,
       Executor executor) {
     super(mediaItem, manifestParser, cacheDataSourceFactory, executor);
+    baseUrlExclusionList = new BaseUrlExclusionList();
   }
 
   @Override
@@ -163,28 +169,32 @@ public final class DashDownloader extends SegmentDownloader<DashManifest> {
         throw new DownloadException("Unbounded segment index");
       }
 
-      String baseUrl = representation.baseUrls.get(0).url;
-      RangedUri initializationUri = representation.getInitializationUri();
+      String baseUrl = castNonNull(baseUrlExclusionList.selectBaseUrl(representation.baseUrls)).url;
+      @Nullable RangedUri initializationUri = representation.getInitializationUri();
       if (initializationUri != null) {
-        addSegment(periodStartUs, baseUrl, initializationUri, out);
+        out.add(createSegment(representation, baseUrl, periodStartUs, initializationUri));
       }
-      RangedUri indexUri = representation.getIndexUri();
+      @Nullable RangedUri indexUri = representation.getIndexUri();
       if (indexUri != null) {
-        addSegment(periodStartUs, baseUrl, indexUri, out);
+        out.add(createSegment(representation, baseUrl, periodStartUs, indexUri));
       }
       long firstSegmentNum = index.getFirstSegmentNum();
       long lastSegmentNum = firstSegmentNum + segmentCount - 1;
       for (long j = firstSegmentNum; j <= lastSegmentNum; j++) {
-        addSegment(periodStartUs + index.getTimeUs(j), baseUrl, index.getSegmentUrl(j), out);
+        out.add(
+            createSegment(
+                representation,
+                baseUrl,
+                periodStartUs + index.getTimeUs(j),
+                index.getSegmentUrl(j)));
       }
     }
   }
 
-  private static void addSegment(
-      long startTimeUs, String baseUrl, RangedUri rangedUri, ArrayList<Segment> out) {
-    DataSpec dataSpec =
-        new DataSpec(rangedUri.resolveUri(baseUrl), rangedUri.start, rangedUri.length);
-    out.add(new Segment(startTimeUs, dataSpec));
+  private Segment createSegment(
+      Representation representation, String baseUrl, long startTimeUs, RangedUri rangedUri) {
+    DataSpec dataSpec = DashUtil.buildDataSpec(representation, baseUrl, rangedUri, /* flags= */ 0);
+    return new Segment(startTimeUs, dataSpec);
   }
 
   @Nullable

library/dash/src/test/java/com/google/android/exoplayer2/source/dash/DashUtilTest.java

@@ -25,6 +25,7 @@ import com.google.android.exoplayer2.drm.DrmInitData.SchemeData;
 import com.google.android.exoplayer2.source.dash.manifest.AdaptationSet;
 import com.google.android.exoplayer2.source.dash.manifest.BaseUrl;
 import com.google.android.exoplayer2.source.dash.manifest.Period;
+import com.google.android.exoplayer2.source.dash.manifest.RangedUri;
 import com.google.android.exoplayer2.source.dash.manifest.Representation;
 import com.google.android.exoplayer2.source.dash.manifest.SegmentBase.SingleSegmentBase;
 import com.google.android.exoplayer2.upstream.DummyDataSource;
@@ -69,6 +70,46 @@ public final class DashUtilTest {
     assertThat(format).isNull();
   }
 
+  @Test
+  public void resolveCacheKey_representationCacheKeyIsNull_resolvesRangedUriWithFirstBaseUrl() {
+    ImmutableList<BaseUrl> baseUrls =
+        ImmutableList.of(new BaseUrl("http://www.google.com"), new BaseUrl("http://www.foo.com"));
+    Representation.SingleSegmentRepresentation representation =
+        new Representation.SingleSegmentRepresentation(
+            /* revisionId= */ 1L,
+            new Format.Builder().build(),
+            baseUrls,
+            new SingleSegmentBase(),
+            /* inbandEventStreams= */ null,
+            /* cacheKey= */ null,
+            /* contentLength= */ 1);
+    RangedUri rangedUri = new RangedUri("path/to/resource", /* start= */ 0, /* length= */ 1);
+
+    String cacheKey = DashUtil.resolveCacheKey(representation, rangedUri);
+
+    assertThat(cacheKey).isEqualTo("http://www.google.com/path/to/resource");
+  }
+
+  @Test
+  public void resolveCacheKey_representationCacheKeyDefined_usesRepresentationCacheKey() {
+    ImmutableList<BaseUrl> baseUrls =
+        ImmutableList.of(new BaseUrl("http://www.google.com"), new BaseUrl("http://www.foo.com"));
+    Representation.SingleSegmentRepresentation representation =
+        new Representation.SingleSegmentRepresentation(
+            /* revisionId= */ 1L,
+            new Format.Builder().build(),
+            baseUrls,
+            new SingleSegmentBase(),
+            /* inbandEventStreams= */ null,
+            "cacheKey",
+            /* contentLength= */ 1);
+    RangedUri rangedUri = new RangedUri("path/to/resource", /* start= */ 0, /* length= */ 1);
+
+    String cacheKey = DashUtil.resolveCacheKey(representation, rangedUri);
+
+    assertThat(cacheKey).isEqualTo("cacheKey");
+  }
+
   private static Period newPeriod(AdaptationSet... adaptationSets) {
     return new Period("", 0, Arrays.asList(adaptationSets));
   }