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