Support MPEG1 audio in the MPEG2-TS stream parser.

media/formats/mpeg/mpeg1_audio_stream_parser.h

+// 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.
+
+#ifndef MEDIA_FORMATS_MPEG_MPEG1_AUDIO_STREAM_PARSER_H_
+#define MEDIA_FORMATS_MPEG_MPEG1_AUDIO_STREAM_PARSER_H_
+
+#include "base/basictypes.h"
+#include "media/base/media_export.h"
+#include "media/formats/mpeg/mpeg_audio_stream_parser_base.h"
+
+namespace media {
+
+// MPEG1AudioStreamParser handles MPEG-1 audio streams (ISO/IEC 11172-3)
+// as well as the following extensions:
+// - MPEG-2 audio (ISO/IEC 13818-3),
+// - and MPEG2.5 (not an ISO standard).
+class MEDIA_EXPORT MPEG1AudioStreamParser : public MPEGAudioStreamParserBase {
+ public:
+  struct Header {
+    int version;

[acolwell GONE FROM CHROMIUM, 2014/09/04 22:20:53]

nit: Since this is a public struct, version and layer should probably be enums
that contain the kVersionXX and kLayerXX values so that other code that uses
this struct doesn't need its own private constants.

[damienv1, 2014/09/05 20:06:13]

Done.

+    int layer;
+    int frame_size;
+    int sample_rate;
+    int channel_mode;
+    ChannelLayout channel_layout;
+    int sample_count;
+  };
+
+  static const int kHeaderSize;
+
+  // Assumption: size of array |data| should be at least the size of an Mpeg1
+  // audio header (i.e. should be greater than or equal to 4).
+  static bool ParseHeader(
+      const LogCB& log_cb,
+      const uint8* data,
+      Header* header);
+
+  MPEG1AudioStreamParser();
+  virtual ~MPEG1AudioStreamParser();
+
+ private:
+  // MPEGAudioStreamParserBase overrides.
+  virtual int ParseFrameHeader(const uint8* data,
+                               int size,
+                               int* frame_size,
+                               int* sample_rate,
+                               ChannelLayout* channel_layout,
+                               int* sample_count,
+                               bool* metadata_frame) const OVERRIDE;
+
+  DISALLOW_COPY_AND_ASSIGN(MPEG1AudioStreamParser);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_FORMATS_MPEG_MPEG1_AUDIO_STREAM_PARSER_H_