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.
5 #ifndef MEDIA_BASE_AUDIO_DECODER_H_
6 #define MEDIA_BASE_AUDIO_DECODER_H_
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"
21 class MEDIA_EXPORT AudioDecoder {
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.
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.
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;
37 // Callback for Decode(). Called after the decoder has completed decoding
38 // corresponding DecoderBuffer, indicating that it's ready to accept another
40 typedef base::Callback<void(Status)> DecodeCB;
43 virtual ~AudioDecoder();
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;
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|.
58 // Implementations guarantee that the callbacks will not be called from within
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;
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;
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;
80 DISALLOW_COPY_AND_ASSIGN(AudioDecoder);
85 #endif // MEDIA_BASE_AUDIO_DECODER_H_