Merge pull request #7064 from davibe:enhancement/6907

PiperOrigin-RevId: 300330109

RELEASENOTES.md

@@ -76,7 +76,10 @@
         MediaSources factories.
 *   Downloads: Merge downloads in `SegmentDownloader` to improve overall
     download speed ([#5978](https://github.com/google/ExoPlayer/issues/5978)).
-*   DASH: Parse period `AssetIdentifier` elements.
+*   DASH:
+    *   Update the manifest URI to avoid repeated HTTP redirects
+        ([#6907](https://github.com/google/ExoPlayer/issues/6907)).
+    *   Parse period `AssetIdentifier` elements.
 *   MP3: Add `IndexSeeker` for accurate seeks in VBR streams
     ([#6787](https://github.com/google/ExoPlayer/issues/6787)). This seeker is
     enabled by passing `FLAG_ENABLE_INDEX_SEEKING` to the `Mp3Extractor`. It may

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

@@ -814,15 +814,18 @@ public final class DashMediaSource extends BaseMediaSource {
     manifestLoadPending &= manifest.dynamic;
     manifestLoadStartTimestampMs = elapsedRealtimeMs - loadDurationMs;
     manifestLoadEndTimestampMs = elapsedRealtimeMs;
-    if (manifest.location != null) {
-      synchronized (manifestUriLock) {
-        // This condition checks that replaceManifestUri wasn't called between the start and end of
-        // this load. If it was, we ignore the manifest location and prefer the manual replacement.
-        @SuppressWarnings("ReferenceEquality")
-        boolean isSameUriInstance = loadable.dataSpec.uri == manifestUri;
-        if (isSameUriInstance) {
-          manifestUri = manifest.location;
-        }
+
+    synchronized (manifestUriLock) {
+      // Checks whether replaceManifestUri(Uri) was called to manually replace the URI between the
+      // start and end of this load. If it was then isSameUriInstance evaluates to false, and we
+      // prefer the manual replacement to one derived from the previous request.
+      @SuppressWarnings("ReferenceEquality")
+      boolean isSameUriInstance = loadable.dataSpec.uri == manifestUri;
+      if (isSameUriInstance) {
+        // Replace the manifest URI with one specified by a manifest Location element (if present),
+        // or with the final (possibly redirected) URI. This follows the recommendation in
+        // DASH-IF-IOP 4.3, section 3.2.15.3. See: https://dashif.org/docs/DASH-IF-IOP-v4.3.pdf.
+        manifestUri = manifest.location != null ? manifest.location : loadable.getUri();
       }
     }