From 4783c329cc545da4269a9401a4975a41e75f2f43 Mon Sep 17 00:00:00 2001
From: aquilescanta <aquilescanta@google.com>
Date: Thu, 22 Oct 2020 21:33:03 +0100
Subject: [PATCH] Map HLS sample formats to the correct codec string

This change fixes format creation for traditional preparation of streams
where the master playlist contains more than one codec string per track
type.

Issue: #7877
PiperOrigin-RevId: 338538693
---
 .../android/exoplayer2/util/MimeTypes.java    | 29 ++++++++++++++---
 .../exoplayer2/util/MimeTypesTest.java        | 31 +++++++++++++++++++
 .../source/hls/HlsSampleStreamWrapper.java    |  6 ++--
 3 files changed, 60 insertions(+), 6 deletions(-)

diff --git a/library/common/src/main/java/com/google/android/exoplayer2/util/MimeTypes.java b/library/common/src/main/java/com/google/android/exoplayer2/util/MimeTypes.java
index 64afcd393a..d6dd67ee7d 100644
--- a/library/common/src/main/java/com/google/android/exoplayer2/util/MimeTypes.java
+++ b/library/common/src/main/java/com/google/android/exoplayer2/util/MimeTypes.java
@@ -250,16 +250,37 @@ public final class MimeTypes {
    */
   public static boolean containsCodecsCorrespondingToMimeType(
       @Nullable String codecs, String mimeType) {
-    if (codecs == null) {
-      return false;
+    return getCodecsCorrespondingToMimeType(codecs, mimeType) != null;
+  }
+
+  /**
+   * Returns a subsequence of {@code codecs} containing the codec strings that correspond to the
+   * given {@code mimeType}. Returns null if {@code mimeType} is null, {@code codecs} is null, or
+   * {@code codecs} does not contain a codec that corresponds to {@code mimeType}.
+   *
+   * @param codecs An RFC 6381 codecs string.
+   * @param mimeType A MIME type to look for.
+   * @return A subsequence of {@code codecs} containing the codec strings that correspond to the
+   *     given {@code mimeType}. Returns null if {@code mimeType} is null, {@code codecs} is null,
+   *     or {@code codecs} does not contain a codec that corresponds to {@code mimeType}.
+   */
+  @Nullable
+  public static String getCodecsCorrespondingToMimeType(
+      @Nullable String codecs, @Nullable String mimeType) {
+    if (codecs == null || mimeType == null) {
+      return null;
     }
     String[] codecList = Util.splitCodecs(codecs);
+    StringBuilder builder = new StringBuilder();
     for (String codec : codecList) {
       if (mimeType.equals(getMediaMimeType(codec))) {
-        return true;
+        if (builder.length() > 0) {
+          builder.append(",");
+        }
+        builder.append(codec);
       }
     }
-    return false;
+    return builder.length() > 0 ? builder.toString() : null;
   }
 
   /**
diff --git a/library/common/src/test/java/com/google/android/exoplayer2/util/MimeTypesTest.java b/library/common/src/test/java/com/google/android/exoplayer2/util/MimeTypesTest.java
index 6f68328dc7..2baac87e85 100644
--- a/library/common/src/test/java/com/google/android/exoplayer2/util/MimeTypesTest.java
+++ b/library/common/src/test/java/com/google/android/exoplayer2/util/MimeTypesTest.java
@@ -60,6 +60,37 @@ public final class MimeTypesTest {
         .isFalse();
   }
 
+  @Test
+  public void getCodecsCorrespondingToMimeType_returnsCorrectResult() {
+    assertThat(
+            MimeTypes.getCodecsCorrespondingToMimeType(
+                /* codecs= */ "avc1.4D5015,ac-3,mp4a.40.2,avc1.4D4015", MimeTypes.AUDIO_AAC))
+        .isEqualTo("mp4a.40.2");
+    assertThat(
+            MimeTypes.getCodecsCorrespondingToMimeType(
+                /* codecs= */ "avc1.4D5015,ac-3,mp4a.40.2,avc1.4D4015", MimeTypes.VIDEO_H264))
+        .isEqualTo("avc1.4D5015,avc1.4D4015");
+    assertThat(
+            MimeTypes.getCodecsCorrespondingToMimeType(
+                /* codecs= */ "avc1.4D5015,ac-3,mp4a.40.2,avc1.4D4015", MimeTypes.AUDIO_AC3))
+        .isEqualTo("ac-3");
+    assertThat(
+            MimeTypes.getCodecsCorrespondingToMimeType(
+                /* codecs= */ "unknown-codec,ac-3,mp4a.40.2,avc1.4D4015", MimeTypes.AUDIO_AC3))
+        .isEqualTo("ac-3");
+
+    assertThat(
+            MimeTypes.getCodecsCorrespondingToMimeType(
+                /* codecs= */ "avc1.4D5015,ac-3,mp4a.40.2,avc1.4D4015", MimeTypes.VIDEO_H265))
+        .isNull();
+    assertThat(
+            MimeTypes.getCodecsCorrespondingToMimeType(
+                /* codecs= */ "avc1.4D5015,ac-3,mp4a.40.2,avc1.4D4015", null))
+        .isNull();
+    assertThat(MimeTypes.getCodecsCorrespondingToMimeType(/* codecs= */ null, MimeTypes.AUDIO_AAC))
+        .isNull();
+  }
+
   @Test
   public void isText_returnsCorrectResult() {
     assertThat(MimeTypes.isText(MimeTypes.TEXT_VTT)).isTrue();
diff --git a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsSampleStreamWrapper.java b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsSampleStreamWrapper.java
index 89e7687a21..7f1af4496f 100644
--- a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsSampleStreamWrapper.java
+++ b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsSampleStreamWrapper.java
@@ -1404,8 +1404,10 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
       return sampleFormat;
     }
 
-    int sampleTrackType = MimeTypes.getTrackType(sampleFormat.sampleMimeType);
-    @Nullable String codecs = Util.getCodecsOfType(playlistFormat.codecs, sampleTrackType);
+    @Nullable
+    String codecs =
+        MimeTypes.getCodecsCorrespondingToMimeType(
+            playlistFormat.codecs, sampleFormat.sampleMimeType);
     @Nullable String sampleMimeType = MimeTypes.getMediaMimeType(codecs);
 
     Format.Builder formatBuilder =