media/formats/mpeg/mpeg_audio_stream_parser_base.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_FORMATS_MPEG_MPEG_AUDIO_STREAM_PARSER_BASE_H_
   6 #define MEDIA_FORMATS_MPEG_MPEG_AUDIO_STREAM_PARSER_BASE_H_
   7
   8 #include <set>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/callback.h"
  13 #include "media/base/audio_decoder_config.h"
  14 #include "media/base/audio_timestamp_helper.h"
  15 #include "media/base/bit_reader.h"
  16 #include "media/base/byte_queue.h"
  17 #include "media/base/media_export.h"
  18 #include "media/base/stream_parser.h"
  19
  20 namespace media {
  21
  22 class MEDIA_EXPORT MPEGAudioStreamParserBase : public StreamParser {
  23  public:
  24   // |start_code_mask| is used to find the start of each frame header.  Also
  25   // referred to as the sync code in the MP3 and ADTS header specifications.
  26   // |codec_delay| is the number of samples the decoder will output before the
  27   // first real frame.
  28   MPEGAudioStreamParserBase(uint32 start_code_mask,
  29                             AudioCodec audio_codec,
  30                             int codec_delay);
  31   ~MPEGAudioStreamParserBase() override;
  32
  33   // StreamParser implementation.
  34   void Init(const InitCB& init_cb,
  35             const NewConfigCB& config_cb,
  36             const NewBuffersCB& new_buffers_cb,
  37             bool ignore_text_tracks,
  38             const EncryptedMediaInitDataCB& encrypted_media_init_data_cb,
  39             const NewMediaSegmentCB& new_segment_cb,
  40             const base::Closure& end_of_segment_cb,
  41             const scoped_refptr<MediaLog>& media_log) override;
  42   void Flush() override;
  43   bool Parse(const uint8* buf, int size) override;
  44
  45  protected:
  46   // Subclasses implement this method to parse format specific frame headers.
  47   // |data| & |size| describe the data available for parsing.
  48   //
  49   // Implementations are expected to consume an entire frame header.  It should
  50   // only return a value greater than 0 when |data| has enough bytes to
  51   // successfully parse & consume the entire frame header.
  52   //
  53   // |frame_size| - Required parameter that is set to the size of the frame, in
  54   // bytes, including the frame header if the function returns a value > 0.
  55   // |sample_rate| - Optional parameter that is set to the sample rate
  56   // of the frame if this function returns a value > 0.
  57   // |channel_layout| - Optional parameter that is set to the channel_layout
  58   // of the frame if this function returns a value > 0.
  59   // |sample_count| - Optional parameter that is set to the number of samples
  60   // in the frame if this function returns a value > 0.
  61   // |metadata_frame| - Optional parameter that is set to true if the frame has
  62   // valid values for the above parameters, but no usable encoded data; only set
  63   // to true if this function returns a value > 0.
  64   //
  65   // |sample_rate|, |channel_layout|, |sample_count|, |metadata_frame| may be
  66   // NULL if the caller is not interested in receiving these values from the
  67   // frame header.
  68   //
  69   // If |metadata_frame| is true, the MPEGAudioStreamParserBase will discard the
  70   // frame after consuming the metadata values above.
  71   //
  72   // Returns:
  73   // > 0 : The number of bytes parsed.
  74   //   0 : If more data is needed to parse the entire frame header.
  75   // < 0 : An error was encountered during parsing.
  76   virtual int ParseFrameHeader(const uint8* data,
  77                                int size,
  78                                int* frame_size,
  79                                int* sample_rate,
  80                                ChannelLayout* channel_layout,
  81                                int* sample_count,
  82                                bool* metadata_frame) const = 0;
  83
  84   const scoped_refptr<MediaLog>& media_log() const { return media_log_; }
  85
  86  private:
  87   enum State {
  88     UNINITIALIZED,
  89     INITIALIZED,
  90     PARSE_ERROR
  91   };
  92
  93   void ChangeState(State state);
  94
  95   // Parsing functions for various byte stream elements.  |data| & |size|
  96   // describe the data available for parsing.
  97   //
  98   // Returns:
  99   // > 0 : The number of bytes parsed.
 100   //   0 : If more data is needed to parse the entire element.
 101   // < 0 : An error was encountered during parsing.
 102   int ParseFrame(const uint8* data, int size, BufferQueue* buffers);
 103   int ParseIcecastHeader(const uint8* data, int size);
 104   int ParseID3v1(const uint8* data, int size);
 105   int ParseID3v2(const uint8* data, int size);
 106
 107   // Parses an ID3v2 "sync safe" integer.
 108   // |reader| - A BitReader to read from.
 109   // |value| - Set to the integer value read, if true is returned.
 110   //
 111   // Returns true if the integer was successfully parsed and |value|
 112   // was set.
 113   // Returns false if an error was encountered. The state of |value| is
 114   // undefined when false is returned.
 115   bool ParseSyncSafeInt(BitReader* reader, int32* value);
 116
 117   // Scans |data| for the next valid start code.
 118   // Returns:
 119   // > 0 : The number of bytes that should be skipped to reach the
 120   //       next start code..
 121   //   0 : If a valid start code was not found and more data is needed.
 122   // < 0 : An error was encountered during parsing.
 123   int FindNextValidStartCode(const uint8* data, int size) const;
 124
 125   // Sends the buffers in |buffers| to |new_buffers_cb_| and then clears
 126   // |buffers|.
 127   // If |end_of_segment| is set to true, then |end_of_segment_cb_| is called
 128   // after |new_buffers_cb_| to signal that these buffers represent the end of a
 129   // media segment.
 130   // Returns true if the buffers are sent successfully.
 131   bool SendBuffers(BufferQueue* buffers, bool end_of_segment);
 132
 133   State state_;
 134
 135   InitCB init_cb_;
 136   NewConfigCB config_cb_;
 137   NewBuffersCB new_buffers_cb_;
 138   NewMediaSegmentCB new_segment_cb_;
 139   base::Closure end_of_segment_cb_;
 140   scoped_refptr<MediaLog> media_log_;
 141
 142   ByteQueue queue_;
 143
 144   AudioDecoderConfig config_;
 145   scoped_ptr<AudioTimestampHelper> timestamp_helper_;
 146   bool in_media_segment_;
 147   const uint32 start_code_mask_;
 148   const AudioCodec audio_codec_;
 149   const int codec_delay_;
 150
 151   DISALLOW_COPY_AND_ASSIGN(MPEGAudioStreamParserBase);
 152 };
 153
 154 }  // namespace media
 155
 156 #endif  // MEDIA_FORMATS_MPEG_MPEG_AUDIO_STREAM_PARSER_BASE_H_