chromecast/media/api/cast_audio_decoder.h

// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROMECAST_MEDIA_API_CAST_AUDIO_DECODER_H_
#define CHROMECAST_MEDIA_API_CAST_AUDIO_DECODER_H_

#include <memory>

#include "base/functional/callback.h"
#include "base/memory/ref_counted.h"
#include "chromecast/media/api/decoder_buffer_base.h"
#include "chromecast/public/media/decoder_config.h"

namespace base {
class SingleThreadTaskRunner;
}  // namespace base

namespace chromecast {
namespace media {

// Audio decoder interface.
class CastAudioDecoder {
 public:
  enum Status {
    kDecodeOk,
    kDecodeError,
  };

  enum OutputFormat {
    kOutputSigned16,     // Output signed 16-bit interleaved samples.
    kOutputPlanarFloat,  // Output planar float samples.
  };

  // Callback called when a buffer has been decoded. |config| is the actual
  // config of the buffer, which may differ from the config indicated by the
  // wrapper format.
  typedef base::OnceCallback<void(
      Status status,
      const AudioConfig& config,
      scoped_refptr<media::DecoderBufferBase> decoded)>
      DecodeCallback;

  // Creates a CastAudioDecoder instance for the given |config|. Decoding must
  // occur on the same thread as |task_runner|. Returns an empty unique_ptr if
  // the decoder could not be created.
  static std::unique_ptr<CastAudioDecoder> Create(
      scoped_refptr<base::SingleThreadTaskRunner> task_runner,
      const media::AudioConfig& config,
      OutputFormat output_format);

  // Given a CastAudioDecoder::OutputFormat, return the size of each sample in
  // that OutputFormat in bytes.
  static int OutputFormatSizeInBytes(CastAudioDecoder::OutputFormat format);

  virtual ~CastAudioDecoder() = default;

  // Returns the expected config of the next decoded audio. Note that the config
  // may change as more audio is decoded.
  virtual const AudioConfig& GetOutputConfig() const = 0;

  // Converts encoded data to the |output_format|. Must be called on the same
  // thread as |task_runner|. Decoded data will be passed to |decode_callback|.
  // The |decode_callback| will not be called after the CastAudioDecoder
  // instance is destroyed. It is OK to pass an end-of-stream DecoderBuffer as
  // |data|.
  virtual void Decode(scoped_refptr<media::DecoderBufferBase> data,
                      DecodeCallback decode_callback) = 0;
};

}  // namespace media
}  // namespace chromecast

#endif  // CHROMECAST_MEDIA_API_CAST_AUDIO_DECODER_H_