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// Copyright (c) 2012 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/base/audio_renderer_mixer.h"
#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/logging.h"
#include "media/audio/audio_util.h"
#include "media/base/limits.h"
namespace media {
AudioRendererMixer::AudioRendererMixer(
const AudioParameters& input_params, const AudioParameters& output_params,
const scoped_refptr<AudioRendererSink>& sink)
: audio_sink_(sink),
current_audio_delay_milliseconds_(0) {
// Sanity check sample rates.
DCHECK_LE(input_params.sample_rate(), limits::kMaxSampleRate);
DCHECK_GE(input_params.sample_rate(), limits::kMinSampleRate);
DCHECK_LE(output_params.sample_rate(), limits::kMaxSampleRate);
DCHECK_GE(output_params.sample_rate(), limits::kMinSampleRate);
// Only resample if necessary since it's expensive.
if (input_params.sample_rate() != output_params.sample_rate()) {
resampler_.reset(new MultiChannelResampler(
output_params.channels(),
input_params.sample_rate() / static_cast<double>(
output_params.sample_rate()),
base::Bind(&AudioRendererMixer::ProvideInput, base::Unretained(this))));
}
audio_sink_->Initialize(output_params, this);
audio_sink_->Start();
}
AudioRendererMixer::~AudioRendererMixer() {
// AudioRendererSinks must be stopped before being destructed.
audio_sink_->Stop();
// Clean up |mixer_input_audio_data_|.
for (size_t i = 0; i < mixer_input_audio_data_.size(); ++i)
delete [] mixer_input_audio_data_[i];
mixer_input_audio_data_.clear();
// Ensures that all mixer inputs have stopped themselves prior to destruction
// and have called RemoveMixerInput().
DCHECK_EQ(mixer_inputs_.size(), 0U);
}
void AudioRendererMixer::AddMixerInput(
const scoped_refptr<AudioRendererMixerInput>& input) {
base::AutoLock auto_lock(mixer_inputs_lock_);
mixer_inputs_.insert(input);
}
void AudioRendererMixer::RemoveMixerInput(
const scoped_refptr<AudioRendererMixerInput>& input) {
base::AutoLock auto_lock(mixer_inputs_lock_);
mixer_inputs_.erase(input);
}
int AudioRendererMixer::Render(const std::vector<float*>& audio_data,
int number_of_frames,
int audio_delay_milliseconds) {
current_audio_delay_milliseconds_ = audio_delay_milliseconds;
if (resampler_.get())
resampler_->Resample(audio_data, number_of_frames);
else
ProvideInput(audio_data, number_of_frames);
// Always return the full number of frames requested, ProvideInput() will pad
// with silence if it wasn't able to acquire enough data.
return number_of_frames;
}
void AudioRendererMixer::ProvideInput(const std::vector<float*>& audio_data,
int number_of_frames) {
base::AutoLock auto_lock(mixer_inputs_lock_);
// Allocate staging area for each mixer input's audio data on first call. We
// won't know how much to allocate until here because of resampling.
if (mixer_input_audio_data_.size() == 0) {
// TODO(dalecurtis): If we switch to AVX/SSE optimization, we'll need to
// allocate these on 32-byte boundaries and ensure they're sized % 32 bytes.
mixer_input_audio_data_.reserve(audio_data.size());
for (size_t i = 0; i < audio_data.size(); ++i)
mixer_input_audio_data_.push_back(new float[number_of_frames]);
mixer_input_audio_data_size_ = number_of_frames;
}
// Sanity check our inputs.
DCHECK_LE(number_of_frames, mixer_input_audio_data_size_);
DCHECK_EQ(audio_data.size(), mixer_input_audio_data_.size());
// Zero |audio_data| so we're mixing into a clean buffer and return silence if
// we couldn't get enough data from our inputs.
for (size_t i = 0; i < audio_data.size(); ++i)
memset(audio_data[i], 0, number_of_frames * sizeof(*audio_data[i]));
// Have each mixer render its data into an output buffer then mix the result.
for (AudioRendererMixerInputSet::iterator it = mixer_inputs_.begin();
it != mixer_inputs_.end(); ++it) {
const scoped_refptr<AudioRendererMixerInput>& input = *it;
double volume;
input->GetVolume(&volume);
// Nothing to do if the input isn't playing.
if (!input->playing())
continue;
int frames_filled = input->callback()->Render(
mixer_input_audio_data_, number_of_frames,
current_audio_delay_milliseconds_);
if (frames_filled == 0)
continue;
// Volume adjust and mix each mixer input into |audio_data| after rendering.
// TODO(dalecurtis): Optimize with NEON/SSE/AVX vector_fmac from FFmpeg.
for (size_t j = 0; j < audio_data.size(); ++j) {
float* dest = audio_data[j];
float* source = mixer_input_audio_data_[j];
for (int k = 0; k < frames_filled; ++k)
dest[k] += source[k] * static_cast<float>(volume);
}
// No need to clamp values as InterleaveFloatToInt() will take care of this
// for us later when data is transferred to the browser process.
}
}
void AudioRendererMixer::OnRenderError() {
base::AutoLock auto_lock(mixer_inputs_lock_);
// Call each mixer input and signal an error.
for (AudioRendererMixerInputSet::iterator it = mixer_inputs_.begin();
it != mixer_inputs_.end(); ++it) {
(*it)->callback()->OnRenderError();
}
}
} // namespace media
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