Implement experimental MP3 support for Media Source API.

media/mp3/mp3_stream_parser.h

+// Copyright (c) 2013 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_MP3_MP3_STREAM_PARSER_H_
+#define MEDIA_MP3_MP3_STREAM_PARSER_H_
+
+#include <set>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "media/base/audio_decoder_config.h"
+#include "media/base/audio_timestamp_helper.h"
+#include "media/base/byte_queue.h"
+#include "media/base/media_export.h"
+#include "media/base/stream_parser.h"
+
+namespace media {
+
+class BitReader;
+
+namespace mp3 {

[scherkus (not reviewing), 2013/09/03 19:34:22]

FYI / personal pet-peeve but this is a bad example of nested namespace usage
since the class you're namespacing is also prefixed with the namespace name ...
but I'd go w/ the consistency here and stick with things as is since we use
nested namespaces for other StreamParsers

https://groups.google.com/a/chromium.org/forum/#!msg/chromium-dev/RVps606IB_g...

[acolwell GONE FROM CHROMIUM, 2013/09/04 00:48:13]

I'll remove the namespace. The WebM parser doesn't live in its own namespace.
Only the MP4 parser does. We are also only talking about 1 class here so a
namespace seems like overkill anyways.

+
+class MEDIA_EXPORT MP3StreamParser : public StreamParser {
+ public:
+  MP3StreamParser();
+  virtual ~MP3StreamParser();
+
+  virtual void Init(const InitCB& init_cb, const NewConfigCB& config_cb,

[scherkus (not reviewing), 2013/09/03 19:34:22]

// StreamParser implementation.

[acolwell GONE FROM CHROMIUM, 2013/09/04 00:48:13]

Done.

+                    const NewBuffersCB& new_buffers_cb,
+                    const NewTextBuffersCB& text_cb,
+                    const NeedKeyCB& need_key_cb,
+                    const AddTextTrackCB& add_text_track_cb,
+                    const NewMediaSegmentCB& new_segment_cb,
+                    const base::Closure& end_of_segment_cb,
+                    const LogCB& log_cb) OVERRIDE;
+  virtual void Flush() OVERRIDE;
+  virtual bool Parse(const uint8* buf, int size) OVERRIDE;
+
+ private:
+  enum State {
+    UNINITIALIZED,
+    INITIALIZED,
+    PARSE_ERROR
+  };
+
+  State state_;
+
+  InitCB init_cb_;
+  NewConfigCB config_cb_;
+  NewBuffersCB new_buffers_cb_;
+  NewMediaSegmentCB new_segment_cb_;
+  base::Closure end_of_segment_cb_;
+  LogCB log_cb_;
+
+  ByteQueue queue_;
+
+  AudioDecoderConfig config_;
+  scoped_ptr<AudioTimestampHelper> timestamp_helper_;
+  bool in_media_segment_;
+
+  void ChangeState(State state);
+
+  // Parsing functions for various byte stream elements.
+  // |data| & |size| describe the data available for parsing.
+  // These functions are expected to consume an entire frame/header.
+  // It should only return a value greater than 0 when |data| has
+  // enough bytes to successfully parse & consume the entire element.
+  // Returns:
+  // > 0 : The number of bytes parsed.
+  //   0 : If more data is needed to parse the entire element.
+  // < 0 : An error was encountered during parsing.
+  int ParseFrameHeader(const uint8* data, int size,
+                       int* frame_size,
+                       int* sample_rate,

[scherkus (not reviewing), 2013/09/03 19:34:22]

document these last 3 args may be NULL

[acolwell GONE FROM CHROMIUM, 2013/09/04 00:48:13]

Done.

+                       ChannelLayout* channel_layout,
+                       int* sample_count) const;
+  int ParseMP3Frame(const uint8* data, int size);
+  int ParseIcecastHeader(const uint8* data, int size);
+  int ParseID3v1(const uint8* data, int size);
+  int ParseID3v2(const uint8* data, int size);
+
+  // Parses an ID3v2 "sync safe" integer.
+  // |reader| - A BitReader to read from.
+  // |value| - Set to the integer value read, if true is returned.
+  //
+  // Returns true if the integer was successfully parsed and |value|
+  // was set.
+  // Returns false if an error was encountered. The state of |value| is
+  // undefined when false is returned.
+  bool ParseSyncSafeInt(BitReader* reader, int32* value);
+
+  // Scans |data| for the next valid start code.
+  // Returns:
+  // > 0 : The number of bytes that should be skipped to reach the
+  //       next start code..
+  //   0 : If a valid start code was not found and more data is needed.
+  // < 0 : An error was encountered during parsing.
+  int FindNextValidStartCode(const uint8* data, int size) const;
+
+  DISALLOW_COPY_AND_ASSIGN(MP3StreamParser);
+};
+
+}  // namespace mp3
+}  // namespace media
+
+#endif  // MEDIA_MP3_MP3_STREAM_PARSER_H_