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 <string> 9 10#include "base/callback.h" 11#include "base/memory/ref_counted.h" 12#include "media/base/audio_decoder_config.h" 13#include "media/base/channel_layout.h" 14#include "media/base/decoder_buffer.h" 15#include "media/base/media_export.h" 16#include "media/base/pipeline_status.h" 17 18namespace media { 19 20class AudioBuffer; 21class DemuxerStream; 22 23class MEDIA_EXPORT AudioDecoder { 24 public: 25 // Status codes for decode operations. 26 // TODO(rileya): Now that both AudioDecoder and VideoDecoder Status enums 27 // match, break them into a decoder_status.h. 28 enum Status { 29 kOk, // We're all good. 30 kAborted, // We aborted as a result of Reset() or destruction. 31 kDecodeError, // A decoding error occurred. 32 kDecryptError // Decrypting error happened. 33 }; 34 35 // Callback for AudioDecoder to return a decoded frame whenever it becomes 36 // available. Only non-EOS frames should be returned via this callback. 37 typedef base::Callback<void(const scoped_refptr<AudioBuffer>&)> OutputCB; 38 39 // Callback for Decode(). Called after the decoder has completed decoding 40 // corresponding DecoderBuffer, indicating that it's ready to accept another 41 // buffer to decode. 42 typedef base::Callback<void(Status)> DecodeCB; 43 44 AudioDecoder(); 45 46 // Fires any pending callbacks, stops and destroys the decoder. 47 // Note: Since this is a destructor, |this| will be destroyed after this call. 48 // Make sure the callbacks fired from this call doesn't post any task that 49 // depends on |this|. 50 virtual ~AudioDecoder(); 51 52 // Returns the name of the decoder for logging purpose. 53 virtual std::string GetDisplayName() const = 0; 54 55 // Initializes an AudioDecoder with the given DemuxerStream, executing the 56 // callback upon completion. 57 // |statistics_cb| is used to update global pipeline statistics. 58 // |output_cb| is called for decoded audio buffers (see Decode()). 59 virtual void Initialize(const AudioDecoderConfig& config, 60 const PipelineStatusCB& status_cb, 61 const OutputCB& output_cb) = 0; 62 63 // Requests samples to be decoded. Only one decode may be in flight at any 64 // given time. Once the buffer is decoded the decoder calls |decode_cb|. 65 // |output_cb| specified in Initialize() is called for each decoded buffer, 66 // before or after |decode_cb|. 67 // 68 // Implementations guarantee that the callbacks will not be called from within 69 // this method. 70 // 71 // If |buffer| is an EOS buffer then the decoder must be flushed, i.e. 72 // |output_cb| must be called for each frame pending in the queue and 73 // |decode_cb| must be called after that. 74 virtual void Decode(const scoped_refptr<DecoderBuffer>& buffer, 75 const DecodeCB& decode_cb) = 0; 76 77 // Resets decoder state. All pending Decode() requests will be finished or 78 // aborted before |closure| is called. 79 virtual void Reset(const base::Closure& closure) = 0; 80 81 private: 82 DISALLOW_COPY_AND_ASSIGN(AudioDecoder); 83}; 84 85} // namespace media 86 87#endif // MEDIA_BASE_AUDIO_DECODER_H_ 88