From cc5e981e894b4e4ed6dd9d16a0537c87f7b162d6 Mon Sep 17 00:00:00 2001
From: ybai001 <ybai@dolby.com>
Date: Mon, 23 Dec 2019 10:49:03 +0800
Subject: [PATCH] Add AC-4 DRM Support

---
 .../extractor/mp4/FragmentedMp4Extractor.java   |  4 +++-
 .../exoplayer2/source/SampleDataQueue.java      | 17 ++++++++++++-----
 .../android/exoplayer2/source/SampleQueue.java  |  3 ++-
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/FragmentedMp4Extractor.java b/library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/FragmentedMp4Extractor.java
index 1172f8665a..792545b610 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/FragmentedMp4Extractor.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/FragmentedMp4Extractor.java
@@ -1222,6 +1222,7 @@ public class FragmentedMp4Extractor implements Extractor {
    * @throws InterruptedException If the thread is interrupted.
    */
   private boolean readSample(ExtractorInput input) throws IOException, InterruptedException {
+    int outputSampleEncryptionDataSize = 0;
     if (parserState == STATE_READING_SAMPLE_START) {
       if (currentTrackBundle == null) {
         @Nullable TrackBundle currentTrackBundle = getNextFragmentRun(trackBundles);
@@ -1269,6 +1270,7 @@ public class FragmentedMp4Extractor implements Extractor {
       }
       sampleBytesWritten = currentTrackBundle.outputSampleEncryptionData();
       sampleSize += sampleBytesWritten;
+      outputSampleEncryptionDataSize = sampleBytesWritten;
       parserState = STATE_READING_SAMPLE_CONTINUE;
       sampleCurrentNalBytesRemaining = 0;
       isAc4HeaderRequired =
@@ -1338,7 +1340,7 @@ public class FragmentedMp4Extractor implements Extractor {
       }
     } else {
       if (isAc4HeaderRequired) {
-        Ac4Util.getAc4SampleHeader(sampleSize, scratch);
+        Ac4Util.getAc4SampleHeader(sampleSize - outputSampleEncryptionDataSize, scratch);
         int length = scratch.limit();
         output.sampleData(scratch, length);
         sampleSize += length;
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/SampleDataQueue.java b/library/core/src/main/java/com/google/android/exoplayer2/source/SampleDataQueue.java
index 68761cef19..26a95b8de2 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/SampleDataQueue.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/SampleDataQueue.java
@@ -23,6 +23,7 @@ import com.google.android.exoplayer2.extractor.TrackOutput.CryptoData;
 import com.google.android.exoplayer2.source.SampleQueue.SampleExtrasHolder;
 import com.google.android.exoplayer2.upstream.Allocation;
 import com.google.android.exoplayer2.upstream.Allocator;
+import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import java.io.EOFException;
 import java.io.IOException;
@@ -114,11 +115,13 @@ import java.nio.ByteBuffer;
    *
    * @param buffer The buffer to populate.
    * @param extrasHolder The extras holder whose offset should be read and subsequently adjusted.
+   * @param mimeType The MIME type.
    */
-  public void readToBuffer(DecoderInputBuffer buffer, SampleExtrasHolder extrasHolder) {
+  public void readToBuffer(DecoderInputBuffer buffer, SampleExtrasHolder extrasHolder,
+      String mimeType) {
     // Read encryption data if the sample is encrypted.
     if (buffer.isEncrypted()) {
-      readEncryptionData(buffer, extrasHolder);
+      readEncryptionData(buffer, extrasHolder, mimeType);
     }
     // Read sample data, extracting supplemental data into a separate buffer if needed.
     if (buffer.hasSupplementalData()) {
@@ -215,8 +218,10 @@ import java.nio.ByteBuffer;
    *
    * @param buffer The buffer into which the encryption data should be written.
    * @param extrasHolder The extras holder whose offset should be read and subsequently adjusted.
+   * @param mimeType The MIME type.
    */
-  private void readEncryptionData(DecoderInputBuffer buffer, SampleExtrasHolder extrasHolder) {
+  private void readEncryptionData(DecoderInputBuffer buffer, SampleExtrasHolder extrasHolder,
+      String mimeType) {
     long offset = extrasHolder.offset;
 
     // Read the signal byte.
@@ -265,8 +270,10 @@ import java.nio.ByteBuffer;
         encryptedDataSizes[i] = scratch.readUnsignedIntToInt();
       }
     } else {
-      clearDataSizes[0] = 0;
-      encryptedDataSizes[0] = extrasHolder.size - (int) (offset - extrasHolder.offset);
+      int addedHeaderSize = MimeTypes.AUDIO_AC4.equals(mimeType) ? 7 : 0;
+      clearDataSizes[0] = addedHeaderSize;
+      encryptedDataSizes[0] = extrasHolder.size - (int) (offset - extrasHolder.offset)
+          - addedHeaderSize;
     }
 
     // Populate the cryptoInfo.
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/SampleQueue.java b/library/core/src/main/java/com/google/android/exoplayer2/source/SampleQueue.java
index cc15d9d275..bfd3d7c4ed 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/SampleQueue.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/SampleQueue.java
@@ -323,7 +323,8 @@ public class SampleQueue implements TrackOutput {
         readSampleMetadata(
             formatHolder, buffer, formatRequired, loadingFinished, decodeOnlyUntilUs, extrasHolder);
     if (result == C.RESULT_BUFFER_READ && !buffer.isEndOfStream() && !buffer.isFlagsOnly()) {
-      sampleDataQueue.readToBuffer(buffer, extrasHolder);
+      sampleDataQueue.readToBuffer(buffer, extrasHolder,
+          downstreamFormat == null ? null : downstreamFormat.sampleMimeType);
     }
     return result;
   }