Re-add AC3/EAC3 audio demuxing support

media/formats/mp4/mp4_stream_parser.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/formats/mp4/mp4_stream_parser.h"
 
 #include <stddef.h>
 #include <limits>
 #include <utility>
 #include <vector>
@@ skipping 202 matching lines @@
     if (track->media.handler.type == kAudio && !audio_config.IsValidConfig()) {
       RCHECK(!samp_descr.audio_entries.empty());
 
       // It is not uncommon to find otherwise-valid files with incorrect sample
       // description indices, so we fail gracefully in that case.
       if (desc_idx >= samp_descr.audio_entries.size())
         desc_idx = 0;
       const AudioSampleEntry& entry = samp_descr.audio_entries[desc_idx];
       const AAC& aac = entry.esds.aac;
 
-      if (!(entry.format == FOURCC_MP4A ||
-            (entry.format == FOURCC_ENCA &&
-             entry.sinf.format.format == FOURCC_MP4A))) {
+      // For encrypted audio streams entry.format is FOURCC_ENCA and actual
+      // format is in entry.sinf.format.format.
+      FourCC audio_format = (entry.format == FOURCC_ENCA)
+                                ? entry.sinf.format.format
+                                : entry.format;
+
+#if defined(ENABLE_AC3_EAC3_AUDIO_DEMUXING)
+      if (audio_format != FOURCC_MP4A && audio_format != FOURCC_AC_3 &&
+          audio_format != FOURCC_EAC_3) {
+#else
+      if (audio_format != FOURCC_MP4A) {
+#endif
         MEDIA_LOG(ERROR, media_log_) << "Unsupported audio format 0x"
                                      << std::hex << entry.format
                                      << " in stsd box.";
         return false;
       }
 
       uint8_t audio_type = entry.esds.object_type;
-      DVLOG(1) << "audio_type " << std::hex << static_cast<int>(audio_type);
+#if defined(ENABLE_AC3_EAC3_AUDIO_DEMUXING)
+      if (audio_type == kForbidden) {

[ddorwin, 2016/01/07 19:12:43]

Does "forbidden" have a special meaning or would "unsupported" or similar be
better?

[servolk, 2016/01/07 21:17:36]

AFAIK no special meaning, it was just a name chosen for ESDS.object_type enum.
We can rename into kUnsupported or kUnknown in a separate CL.

+        if (audio_format == FOURCC_AC_3)
+          audio_type = kAC3;
+        if (audio_format == FOURCC_EAC_3)
+          audio_type = kEAC3;
+      }
+#endif
+      DVLOG(1) << "audio_type 0x" << std::hex << static_cast<int>(audio_type);
       if (audio_object_types_.find(audio_type) == audio_object_types_.end()) {
         MEDIA_LOG(ERROR, media_log_)
-            << "audio object type 0x" << std::hex << audio_type
-            << " does not match what is specified in the"
-            << " mimetype.";
+            << "audio object type 0x" << std::hex
+            << static_cast<int>(audio_type)
+            << " does not match what is specified in the mimetype.";
         return false;
       }
 
       AudioCodec codec = kUnknownAudioCodec;
       ChannelLayout channel_layout = CHANNEL_LAYOUT_NONE;
       int sample_per_second = 0;
       std::vector<uint8_t> extra_data;
       // Check if it is MPEG4 AAC defined in ISO 14496 Part 3 or
       // supported MPEG2 AAC varients.
       if (ESDescriptor::IsAAC(audio_type)) {
         codec = kCodecAAC;
         channel_layout = aac.GetChannelLayout(has_sbr_);
         sample_per_second = aac.GetOutputSamplesPerSecond(has_sbr_);
 #if defined(OS_ANDROID)
         extra_data = aac.codec_specific_data();
 #endif
+#if defined(ENABLE_AC3_EAC3_AUDIO_DEMUXING)
+      } else if (audio_type == kAC3) {
+        codec = kCodecAC3;
+        channel_layout = GuessChannelLayout(entry.channelcount);
+        sample_per_second = entry.samplerate;
+      } else if (audio_type == kEAC3) {
+        codec = kCodecEAC3;
+        channel_layout = GuessChannelLayout(entry.channelcount);
+        sample_per_second = entry.samplerate;
+#endif
       } else {
         MEDIA_LOG(ERROR, media_log_) << "Unsupported audio object type 0x"
-                                     << std::hex << audio_type << " in esds.";
+                                     << std::hex << static_cast<int>(audio_type)
+                                     << " in esds.";
         return false;
       }
 
       SampleFormat sample_format;
       if (entry.samplesize == 8) {
         sample_format = kSampleFormatU8;
       } else if (entry.samplesize == 16) {
         sample_format = kSampleFormatS16;
       } else if (entry.samplesize == 32) {
         sample_format = kSampleFormatS32;
@@ skipping 359 matching lines @@
       runs.AdvanceSample();
     }
     runs.AdvanceRun();
   }
 
   return true;
 }
 
 }  // namespace mp4
 }  // namespace media