media/filters/ffmpeg_audio_decoder.h

   1 // Copyright (c) 2012 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_FILTERS_FFMPEG_AUDIO_DECODER_H_
   6 #define MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_
   7
   8 #include <list>
   9
  10 #include "base/callback.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "base/time/time.h"
  13 #include "media/base/audio_decoder.h"
  14 #include "media/base/demuxer_stream.h"
  15 #include "media/base/media_log.h"
  16 #include "media/base/sample_format.h"
  17 #include "media/ffmpeg/ffmpeg_deleters.h"
  18
  19 struct AVCodecContext;
  20 struct AVFrame;
  21
  22 namespace base {
  23 class SingleThreadTaskRunner;
  24 }
  25
  26 namespace media {
  27
  28 class AudioDiscardHelper;
  29 class DecoderBuffer;
  30
  31 class MEDIA_EXPORT FFmpegAudioDecoder : public AudioDecoder {
  32  public:
  33   FFmpegAudioDecoder(
  34       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
  35       const scoped_refptr<MediaLog>& media_log);
  36   ~FFmpegAudioDecoder() override;
  37
  38   // AudioDecoder implementation.
  39   std::string GetDisplayName() const override;
  40   void Initialize(const AudioDecoderConfig& config,
  41                   const InitCB& init_cb,
  42                   const OutputCB& output_cb) override;
  43   void Decode(const scoped_refptr<DecoderBuffer>& buffer,
  44               const DecodeCB& decode_cb) override;
  45   void Reset(const base::Closure& closure) override;
  46
  47  private:
  48   // There are four states the decoder can be in:
  49   //
  50   // - kUninitialized: The decoder is not initialized.
  51   // - kNormal: This is the normal state. The decoder is idle and ready to
  52   //            decode input buffers, or is decoding an input buffer.
  53   // - kDecodeFinished: EOS buffer received, codec flushed and decode finished.
  54   //                    No further Decode() call should be made.
  55   // - kError: Unexpected error happened.
  56   //
  57   // These are the possible state transitions.
  58   //
  59   // kUninitialized -> kNormal:
  60   //     The decoder is successfully initialized and is ready to decode buffers.
  61   // kNormal -> kDecodeFinished:
  62   //     When buffer->end_of_stream() is true and avcodec_decode_audio4()
  63   //     returns 0 data.
  64   // kNormal -> kError:
  65   //     A decoding error occurs and decoding needs to stop.
  66   // (any state) -> kNormal:
  67   //     Any time Reset() is called.
  68   enum DecoderState {
  69     kUninitialized,
  70     kNormal,
  71     kDecodeFinished,
  72     kError
  73   };
  74
  75   // Reset decoder and call |reset_cb_|.
  76   void DoReset();
  77
  78   // Handles decoding an unencrypted encoded buffer.
  79   void DecodeBuffer(const scoped_refptr<DecoderBuffer>& buffer,
  80                     const DecodeCB& decode_cb);
  81   bool FFmpegDecode(const scoped_refptr<DecoderBuffer>& buffer,
  82                     bool* has_produced_frame);
  83
  84   // Handles (re-)initializing the decoder with a (new) config.
  85   // Returns true if initialization was successful.
  86   bool ConfigureDecoder();
  87
  88   // Releases resources associated with |codec_context_| and |av_frame_|
  89   // and resets them to NULL.
  90   void ReleaseFFmpegResources();
  91   void ResetTimestampState();
  92
  93   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  94
  95   OutputCB output_cb_;
  96
  97   DecoderState state_;
  98
  99   // FFmpeg structures owned by this object.
 100   scoped_ptr<AVCodecContext, ScopedPtrAVFreeContext> codec_context_;
 101   scoped_ptr<AVFrame, ScopedPtrAVFreeFrame> av_frame_;
 102
 103   AudioDecoderConfig config_;
 104
 105   // AVSampleFormat initially requested; not Chrome's SampleFormat.
 106   int av_sample_format_;
 107
 108   scoped_ptr<AudioDiscardHelper> discard_helper_;
 109
 110   scoped_refptr<MediaLog> media_log_;
 111
 112   DISALLOW_IMPLICIT_CONSTRUCTORS(FFmpegAudioDecoder);
 113 };
 114
 115 }  // namespace media
 116
 117 #endif  // MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_