audio_decoder.h revision c2e0dbddbe15c98d52c4786dac06cb8952a8ae6d
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_BASE_AUDIO_DECODER_H_ 6#define MEDIA_BASE_AUDIO_DECODER_H_ 7 8#include "base/callback.h" 9#include "base/memory/ref_counted.h" 10#include "media/base/channel_layout.h" 11#include "media/base/pipeline_status.h" 12#include "media/base/media_export.h" 13 14namespace media { 15 16class DataBuffer; 17class DemuxerStream; 18 19class MEDIA_EXPORT AudioDecoder { 20 public: 21 // Status codes for read operations. 22 enum Status { 23 kOk, 24 kAborted, 25 kDecodeError, 26 }; 27 28 AudioDecoder(); 29 virtual ~AudioDecoder(); 30 31 // Initialize an AudioDecoder with the given DemuxerStream, executing the 32 // callback upon completion. 33 // statistics_cb is used to update global pipeline statistics. 34 virtual void Initialize(DemuxerStream* stream, 35 const PipelineStatusCB& status_cb, 36 const StatisticsCB& statistics_cb) = 0; 37 38 // Request samples to be decoded and returned via the provided callback. 39 // Only one read may be in flight at any given time. 40 // 41 // Implementations guarantee that the callback will not be called from within 42 // this method. 43 // 44 // Non-NULL sample buffer pointers will contain decoded audio data or may 45 // indicate the end of the stream. A NULL buffer pointer indicates an aborted 46 // Read(). This can happen if the DemuxerStream gets flushed and doesn't have 47 // any more data to return. 48 typedef base::Callback<void(Status, const scoped_refptr<DataBuffer>&)> ReadCB; 49 virtual void Read(const ReadCB& read_cb) = 0; 50 51 // Reset decoder state, dropping any queued encoded data. 52 virtual void Reset(const base::Closure& closure) = 0; 53 54 // Returns various information about the decoded audio format. 55 virtual int bits_per_channel() = 0; 56 virtual ChannelLayout channel_layout() = 0; 57 virtual int samples_per_second() = 0; 58 59 private: 60 DISALLOW_COPY_AND_ASSIGN(AudioDecoder); 61}; 62 63} // namespace media 64 65#endif // MEDIA_BASE_AUDIO_DECODER_H_ 66