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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_BASE_AUDIO_DECODER_H_
#define MEDIA_BASE_AUDIO_DECODER_H_
#include "base/callback.h"
#include "base/memory/ref_counted.h"
#include "media/base/audio_decoder_config.h"
#include "media/base/channel_layout.h"
#include "media/base/decoder.h"
#include "media/base/decoder_buffer.h"
#include "media/base/decoder_status.h"
#include "media/base/media_export.h"
#include "media/base/pipeline_status.h"
#include "media/base/waiting.h"
namespace media {
class AudioBuffer;
class CdmContext;
class MEDIA_EXPORT AudioDecoder : public Decoder {
public:
// Callback for Decoder initialization.
using InitCB = base::OnceCallback<void(DecoderStatus)>;
// Callback for AudioDecoder to return a decoded frame whenever it becomes
// available. Only non-EOS frames should be returned via this callback.
using OutputCB = base::RepeatingCallback<void(scoped_refptr<AudioBuffer>)>;
// Callback type for Decode(). Called after the decoder has completed decoding
// corresponding DecoderBuffer, indicating that it's ready to accept another
// buffer to decode. |kOk| implies success, |kAborted| implies that the
// decode was aborted, which does not necessarily indicate an error. For
// example, a Reset() can trigger this. Any other status code indicates that
// the decoder encountered an error, and must be reset.
using DecodeCB = base::OnceCallback<void(DecoderStatus)>;
AudioDecoder();
AudioDecoder(const AudioDecoder&) = delete;
AudioDecoder& operator=(const AudioDecoder&) = delete;
// Fires any pending callbacks, stops and destroys the decoder.
// Note: Since this is a destructor, |this| will be destroyed after this call.
// Make sure the callbacks fired from this call doesn't post any task that
// depends on |this|.
~AudioDecoder() override;
// Initializes an AudioDecoder with |config|, executing the |init_cb| upon
// completion.
//
// |cdm_context| can be used to handle encrypted buffers. May be null if the
// stream is not encrypted.
// |init_cb| is used to return initialization status.
// |output_cb| is called for decoded audio buffers (see Decode()).
// |waiting_cb| is called whenever the decoder is stalled waiting for
// something, e.g. decryption key. May be called at any time after
// Initialize().
virtual void Initialize(const AudioDecoderConfig& config,
CdmContext* cdm_context,
InitCB init_cb,
const OutputCB& output_cb,
const WaitingCB& waiting_cb) = 0;
// Requests samples to be decoded. Only one decode may be in flight at any
// given time. Once the buffer is decoded the decoder calls |decode_cb|.
// |output_cb| specified in Initialize() is called for each decoded buffer,
// before or after |decode_cb|.
//
// Implementations guarantee that the callbacks will not be called from within
// this method.
//
// If |buffer| is an EOS buffer then the decoder must be flushed, i.e.
// |output_cb| must be called for each frame pending in the queue and
// |decode_cb| must be called after that.
virtual void Decode(scoped_refptr<DecoderBuffer> buffer,
DecodeCB decode_cb) = 0;
// Resets decoder state. All pending Decode() requests will be finished or
// aborted before |closure| is called.
virtual void Reset(base::OnceClosure closure) = 0;
// Returns true if the decoder needs bitstream conversion before decoding.
virtual bool NeedsBitstreamConversion() const;
// Returns the type of the decoder for statistics recording purposes.
virtual AudioDecoderType GetDecoderType() const = 0;
};
} // namespace media
#endif // MEDIA_BASE_AUDIO_DECODER_H_
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