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      1 // Copyright 2013 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_CDM_PPAPI_FFMPEG_CDM_AUDIO_DECODER_H_
      6 #define MEDIA_CDM_PPAPI_FFMPEG_CDM_AUDIO_DECODER_H_
      7 
      8 #include <vector>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/compiler_specific.h"
     12 #include "base/memory/scoped_ptr.h"
     13 #include "base/time/time.h"
     14 #include "media/cdm/ppapi/clear_key_cdm_common.h"
     15 
     16 struct AVCodecContext;
     17 struct AVFrame;
     18 
     19 namespace media {
     20 class AudioBus;
     21 class AudioTimestampHelper;
     22 class ScopedPtrAVFreeContext;
     23 class ScopedPtrAVFreeFrame;
     24 }
     25 
     26 namespace media {
     27 // TODO(xhwang): This class is partially cloned from FFmpegAudioDecoder. When
     28 // FFmpegAudioDecoder is updated, it's a pain to keep this class in sync with
     29 // FFmpegAudioDecoder. We need a long term sustainable solution for this. See
     30 // http://crbug.com/169203
     31 class FFmpegCdmAudioDecoder {
     32  public:
     33   explicit FFmpegCdmAudioDecoder(ClearKeyCdmHost* host);
     34   ~FFmpegCdmAudioDecoder();
     35   bool Initialize(const cdm::AudioDecoderConfig& config);
     36   void Deinitialize();
     37   void Reset();
     38 
     39   // Returns true when |config| is a valid audio decoder configuration.
     40   static bool IsValidConfig(const cdm::AudioDecoderConfig& config);
     41 
     42   // Decodes |compressed_buffer|. Returns |cdm::kSuccess| after storing
     43   // output in |decoded_frames| when output is available. Returns
     44   // |cdm::kNeedMoreData| when |compressed_frame| does not produce output.
     45   // Returns |cdm::kDecodeError| when decoding fails.
     46   //
     47   // A null |compressed_buffer| will attempt to flush the decoder of any
     48   // remaining frames. |compressed_buffer_size| and |timestamp| are ignored.
     49   cdm::Status DecodeBuffer(const uint8_t* compressed_buffer,
     50                            int32_t compressed_buffer_size,
     51                            int64_t timestamp,
     52                            cdm::AudioFrames* decoded_frames);
     53 
     54  private:
     55   void ResetTimestampState();
     56   void ReleaseFFmpegResources();
     57 
     58   base::TimeDelta GetNextOutputTimestamp() const;
     59 
     60   void SerializeInt64(int64_t value);
     61 
     62   bool is_initialized_;
     63 
     64   ClearKeyCdmHost* const host_;
     65 
     66   // FFmpeg structures owned by this object.
     67   scoped_ptr_malloc<AVCodecContext, ScopedPtrAVFreeContext> codec_context_;
     68   scoped_ptr_malloc<AVFrame, ScopedPtrAVFreeFrame> av_frame_;
     69 
     70   // Audio format.
     71   int samples_per_second_;
     72   int channels_;
     73 
     74   // AVSampleFormat initially requested; not Chrome's SampleFormat.
     75   int av_sample_format_;
     76 
     77   // Used for computing output timestamps.
     78   scoped_ptr<AudioTimestampHelper> output_timestamp_helper_;
     79   int bytes_per_frame_;
     80   base::TimeDelta last_input_timestamp_;
     81 
     82   // Number of output sample bytes to drop before generating output buffers.
     83   // This is required for handling negative timestamps when decoding Vorbis
     84   // audio, for example.
     85   int output_bytes_to_drop_;
     86 
     87   typedef std::vector<uint8_t> SerializedAudioFrames;
     88   SerializedAudioFrames serialized_audio_frames_;
     89 
     90   DISALLOW_COPY_AND_ASSIGN(FFmpegCdmAudioDecoder);
     91 };
     92 
     93 }  // namespace media
     94 
     95 #endif  // MEDIA_CDM_PPAPI_FFMPEG_CDM_AUDIO_DECODER_H_
     96