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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// Creates a unified stream based on the cras (ChromeOS audio server) interface.
//
// CrasUnifiedStream object is *not* thread-safe and should only be used
// from the audio thread.
#ifndef MEDIA_AUDIO_LINUX_CRAS_UNIFIED_H_
#define MEDIA_AUDIO_LINUX_CRAS_UNIFIED_H_
#include <cras_client.h>
#include "base/compiler_specific.h"
#include "media/audio/audio_io.h"
#include "media/audio/audio_parameters.h"
namespace media {
class AudioManagerCras;
// Implementation of AudioOuputStream for Chrome OS using the Chrome OS audio
// server.
// TODO(dgreid): This class is used for only output, either remove all the
// relevant input code and change the class to CrasOutputStream or merge
// cras_input.cc into this unified implementation.
class MEDIA_EXPORT CrasUnifiedStream : public AudioOutputStream {
public:
// The ctor takes all the usual parameters, plus |manager| which is the
// audio manager who is creating this object.
CrasUnifiedStream(const AudioParameters& params, AudioManagerCras* manager);
// The dtor is typically called by the AudioManager only and it is usually
// triggered by calling AudioUnifiedStream::Close().
~CrasUnifiedStream() override;
// Implementation of AudioOutputStream.
bool Open() override;
void Close() override;
void Start(AudioSourceCallback* callback) override;
void Stop() override;
void SetVolume(double volume) override;
void GetVolume(double* volume) override;
private:
// Convert Latency in time to bytes.
uint32_t GetBytesLatency(const struct timespec& latency);
// Handles captured audio and fills the ouput with audio to be played.
static int UnifiedCallback(cras_client* client,
cras_stream_id_t stream_id,
uint8_t* input_samples,
uint8_t* output_samples,
unsigned int frames,
const timespec* input_ts,
const timespec* output_ts,
void* arg);
// Handles notification that there was an error with the playback stream.
static int StreamError(cras_client* client,
cras_stream_id_t stream_id,
int err,
void* arg);
// Chooses the correct audio callback based on stream direction.
uint32_t DispatchCallback(size_t frames,
uint8_t* input_samples,
uint8_t* output_samples,
const timespec* input_ts,
const timespec* output_ts);
// Writes audio for a playback stream.
uint32_t WriteAudio(size_t frames,
uint8_t* buffer,
const timespec* sample_ts);
// Deals with an error that occured in the stream. Called from StreamError().
void NotifyStreamError(int err);
// The client used to communicate with the audio server.
cras_client* client_;
// ID of the playing stream.
cras_stream_id_t stream_id_;
// PCM parameters for the stream.
AudioParameters params_;
// Size of frame in bytes.
uint32_t bytes_per_frame_;
// True if stream is playing.
bool is_playing_;
// Volume level from 0.0 to 1.0.
float volume_;
// Audio manager that created us. Used to report that we've been closed.
AudioManagerCras* manager_;
// Callback to get audio samples.
AudioSourceCallback* source_callback_;
// Container for exchanging data with AudioSourceCallback::OnMoreData().
scoped_ptr<AudioBus> output_bus_;
// Direciton of the stream.
CRAS_STREAM_DIRECTION stream_direction_;
DISALLOW_COPY_AND_ASSIGN(CrasUnifiedStream);
};
} // namespace media
#endif // MEDIA_AUDIO_LINUX_CRAS_UNIFIED_H_
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