// 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.
#include "media/audio/cras/cras_unified.h"
#include "base/logging.h"
#include "media/audio/cras/audio_manager_cras.h"
namespace media {
// Overview of operation:
// 1) An object of CrasUnifiedStream is created by the AudioManager
// factory: audio_man->MakeAudioStream().
// 2) Next some thread will call Open(), at that point a client is created and
// configured for the correct format and sample rate.
// 3) Then Start(source) is called and a stream is added to the CRAS client
// which will create its own thread that periodically calls the source for more
// data as buffers are being consumed.
// 4) When finished Stop() is called, which is handled by stopping the stream.
// 5) Finally Close() is called. It cleans up and notifies the audio manager,
// which likely will destroy this object.
//
// For output-only streams, a unified stream is created with 0 input channels.
//
// Simplified data flow for unified streams:
//
// +-------------+ +------------------+
// | CRAS Server | | Chrome Client |
// +------+------+ Add Stream +---------+--------+
// |<----------------------------------|
// | |
// | buffer_frames captured to shm |
// |---------------------------------->|
// | | UnifiedCallback()
// | | ReadWriteAudio()
// | |
// | buffer_frames written to shm |
// |<----------------------------------|
// | |
// ... Repeats for each block. ...
// | |
// | |
// | Remove stream |
// |<----------------------------------|
// | |
//
// Simplified data flow for output only streams:
//
// +-------------+ +------------------+
// | CRAS Server | | Chrome Client |
// +------+------+ Add Stream +---------+--------+
// |<----------------------------------|
// | |
// | Near out of samples, request more |
// |---------------------------------->|
// | | UnifiedCallback()
// | | WriteAudio()
// | |
// | buffer_frames written to shm |
// |<----------------------------------|
// | |
// ... Repeats for each block. ...
// | |
// | |
// | Remove stream |
// |<----------------------------------|
// | |
//
// For Unified streams the Chrome client is notified whenever buffer_frames have
// been captured. For Output streams the client is notified a few milliseconds
// before the hardware buffer underruns and fills the buffer with another block
// of audio.
CrasUnifiedStream::CrasUnifiedStream(const AudioParameters& params,
AudioManagerCras* manager)
: client_(NULL),
stream_id_(0),
params_(params),
bytes_per_frame_(0),
is_playing_(false),
volume_(1.0),
manager_(manager),
source_callback_(NULL),
stream_direction_(CRAS_STREAM_OUTPUT) {
DCHECK(manager_);
DCHECK(params_.channels() > 0);
// Must have at least one input or output. If there are both they must be the
// same.
int input_channels = params_.input_channels();
if (input_channels) {
// A unified stream for input and output.
DCHECK(params_.channels() == input_channels);
stream_direction_ = CRAS_STREAM_UNIFIED;
input_bus_ = AudioBus::Create(input_channels,
params_.frames_per_buffer());
}
output_bus_ = AudioBus::Create(params);
}
CrasUnifiedStream::~CrasUnifiedStream() {
DCHECK(!is_playing_);
}
bool CrasUnifiedStream::Open() {
// Sanity check input values.
if (params_.sample_rate() <= 0) {
LOG(WARNING) << "Unsupported audio frequency.";
return false;
}
if (AudioManagerCras::BitsToFormat(params_.bits_per_sample()) ==
SND_PCM_FORMAT_UNKNOWN) {
LOG(WARNING) << "Unsupported pcm format";
return false;
}
// Create the client and connect to the CRAS server.
if (cras_client_create(&client_)) {
LOG(WARNING) << "Couldn't create CRAS client.\n";
client_ = NULL;
return false;
}
if (cras_client_connect(client_)) {
LOG(WARNING) << "Couldn't connect CRAS client.\n";
cras_client_destroy(client_);
client_ = NULL;
return false;
}
// Then start running the client.
if (cras_client_run_thread(client_)) {
LOG(WARNING) << "Couldn't run CRAS client.\n";
cras_client_destroy(client_);
client_ = NULL;
return false;
}
return true;
}
void CrasUnifiedStream::Close() {
if (client_) {
cras_client_stop(client_);
cras_client_destroy(client_);
client_ = NULL;
}
// Signal to the manager that we're closed and can be removed.
// Should be last call in the method as it deletes "this".
manager_->ReleaseOutputStream(this);
}
void CrasUnifiedStream::Start(AudioSourceCallback* callback) {
CHECK(callback);
// Channel map to CRAS_CHANNEL, values in the same order of
// corresponding source in Chromium defined Channels.
static const int kChannelMap[] = {
CRAS_CH_FL,
CRAS_CH_FR,
CRAS_CH_FC,
CRAS_CH_LFE,
CRAS_CH_RL,
CRAS_CH_RR,
CRAS_CH_FLC,
CRAS_CH_FRC,
CRAS_CH_RC,
CRAS_CH_SL,
CRAS_CH_SR
};
source_callback_ = callback;
// Only start if we can enter the playing state.
if (is_playing_)
return;
// Prepare |audio_format| and |stream_params| for the stream we
// will create.
cras_audio_format* audio_format = cras_audio_format_create(
AudioManagerCras::BitsToFormat(params_.bits_per_sample()),
params_.sample_rate(),
params_.channels());
if (!audio_format) {
LOG(WARNING) << "Error setting up audio parameters.";
callback->OnError(this);
return;
}
// Initialize channel layout to all -1 to indicate that none of
// the channels is set in the layout.
int8 layout[CRAS_CH_MAX] = {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 };
// Converts to CRAS defined channels. ChannelOrder will return -1
// for channels that does not present in params_.channel_layout().
for (size_t i = 0; i < arraysize(kChannelMap); ++i)
layout[kChannelMap[i]] = ChannelOrder(params_.channel_layout(),
static_cast<Channels>(i));
if (cras_audio_format_set_channel_layout(audio_format, layout)) {
LOG(WARNING) << "Error setting channel layout.";
callback->OnError(this);
return;
}
cras_stream_params* stream_params = cras_client_unified_params_create(
stream_direction_,
params_.frames_per_buffer(),
CRAS_STREAM_TYPE_DEFAULT,
0,
this,
CrasUnifiedStream::UnifiedCallback,
CrasUnifiedStream::StreamError,
audio_format);
if (!stream_params) {
LOG(WARNING) << "Error setting up stream parameters.";
callback->OnError(this);
cras_audio_format_destroy(audio_format);
return;
}
// Before starting the stream, save the number of bytes in a frame for use in
// the callback.
bytes_per_frame_ = cras_client_format_bytes_per_frame(audio_format);
// Adding the stream will start the audio callbacks requesting data.
if (cras_client_add_stream(client_, &stream_id_, stream_params) < 0) {
LOG(WARNING) << "Failed to add the stream";
callback->OnError(this);
cras_audio_format_destroy(audio_format);
cras_client_stream_params_destroy(stream_params);
return;
}
// Set initial volume.
cras_client_set_stream_volume(client_, stream_id_, volume_);
// Done with config params.
cras_audio_format_destroy(audio_format);
cras_client_stream_params_destroy(stream_params);
is_playing_ = true;
}
void CrasUnifiedStream::Stop() {
if (!client_)
return;
// Removing the stream from the client stops audio.
cras_client_rm_stream(client_, stream_id_);
is_playing_ = false;
}
void CrasUnifiedStream::SetVolume(double volume) {
if (!client_)
return;
volume_ = static_cast<float>(volume);
cras_client_set_stream_volume(client_, stream_id_, volume_);
}
void CrasUnifiedStream::GetVolume(double* volume) {
*volume = volume_;
}
uint32 CrasUnifiedStream::GetBytesLatency(
const struct timespec& latency_ts) {
uint32 latency_usec;
// Treat negative latency (if we are too slow to render) as 0.
if (latency_ts.tv_sec < 0 || latency_ts.tv_nsec < 0) {
latency_usec = 0;
} else {
latency_usec = (latency_ts.tv_sec * base::Time::kMicrosecondsPerSecond) +
latency_ts.tv_nsec / base::Time::kNanosecondsPerMicrosecond;
}
double frames_latency =
latency_usec * params_.sample_rate() / base::Time::kMicrosecondsPerSecond;
return static_cast<unsigned int>(frames_latency * bytes_per_frame_);
}
// Static callback asking for samples.
int CrasUnifiedStream::UnifiedCallback(cras_client* client,
cras_stream_id_t stream_id,
uint8* input_samples,
uint8* output_samples,
unsigned int frames,
const timespec* input_ts,
const timespec* output_ts,
void* arg) {
CrasUnifiedStream* me = static_cast<CrasUnifiedStream*>(arg);
return me->DispatchCallback(frames,
input_samples,
output_samples,
input_ts,
output_ts);
}
// Static callback for stream errors.
int CrasUnifiedStream::StreamError(cras_client* client,
cras_stream_id_t stream_id,
int err,
void* arg) {
CrasUnifiedStream* me = static_cast<CrasUnifiedStream*>(arg);
me->NotifyStreamError(err);
return 0;
}
// Calls the appropriate rendering function for this type of stream.
uint32 CrasUnifiedStream::DispatchCallback(size_t frames,
uint8* input_samples,
uint8* output_samples,
const timespec* input_ts,
const timespec* output_ts) {
switch (stream_direction_) {
case CRAS_STREAM_OUTPUT:
return WriteAudio(frames, output_samples, output_ts);
case CRAS_STREAM_INPUT:
NOTREACHED() << "CrasUnifiedStream doesn't support input streams.";
return 0;
case CRAS_STREAM_UNIFIED:
return ReadWriteAudio(frames, input_samples, output_samples,
input_ts, output_ts);
default:
break;
}
return 0;
}
// Note these are run from a real time thread, so don't waste cycles here.
uint32 CrasUnifiedStream::ReadWriteAudio(size_t frames,
uint8* input_samples,
uint8* output_samples,
const timespec* input_ts,
const timespec* output_ts) {
DCHECK_EQ(frames, static_cast<size_t>(output_bus_->frames()));
DCHECK(source_callback_);
uint32 bytes_per_sample = bytes_per_frame_ / params_.channels();
input_bus_->FromInterleaved(input_samples, frames, bytes_per_sample);
// Determine latency and pass that on to the source. We have the capture time
// of the first input sample and the playback time of the next audio sample
// passed from the audio server, add them together for total latency.
uint32 total_delay_bytes;
timespec latency_ts = {0, 0};
cras_client_calc_capture_latency(input_ts, &latency_ts);
total_delay_bytes = GetBytesLatency(latency_ts);
cras_client_calc_playback_latency(output_ts, &latency_ts);
total_delay_bytes += GetBytesLatency(latency_ts);
int frames_filled = source_callback_->OnMoreData(
output_bus_.get(),
AudioBuffersState(0, total_delay_bytes));
output_bus_->ToInterleaved(frames_filled, bytes_per_sample, output_samples);
return frames_filled;
}
uint32 CrasUnifiedStream::WriteAudio(size_t frames,
uint8* buffer,
const timespec* sample_ts) {
DCHECK_EQ(frames, static_cast<size_t>(output_bus_->frames()));
// Determine latency and pass that on to the source.
timespec latency_ts = {0, 0};
cras_client_calc_playback_latency(sample_ts, &latency_ts);
int frames_filled = source_callback_->OnMoreData(
output_bus_.get(), AudioBuffersState(0, GetBytesLatency(latency_ts)));
// Note: If this ever changes to output raw float the data must be clipped and
// sanitized since it may come from an untrusted source such as NaCl.
output_bus_->ToInterleaved(
frames_filled, bytes_per_frame_ / params_.channels(), buffer);
return frames_filled;
}
void CrasUnifiedStream::NotifyStreamError(int err) {
// This will remove the stream from the client.
if (source_callback_)
source_callback_->OnError(this);
}
} // namespace media