| /* |
| * Copyright 2015 Google Inc. All Rights Reserved. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "cobalt/audio/audio_node_input.h" |
| |
| #include "base/logging.h" |
| #include "cobalt/audio/audio_context.h" |
| #include "cobalt/audio/audio_node.h" |
| #include "cobalt/audio/audio_node_output.h" |
| |
| namespace cobalt { |
| namespace audio { |
| |
| namespace { |
| |
| typedef ::media::ShellAudioBus ShellAudioBus; |
| |
| void MixAudioBufferBasedOnInterpretation( |
| const float* speaker, const float* discrete, |
| const AudioNode::ChannelInterpretation& interpretation, |
| ShellAudioBus* source, ShellAudioBus* output_audio_data) { |
| const float* kMatrix = |
| interpretation == AudioNode::kSpeakers ? speaker : discrete; |
| size_t array_size = source->channels() * output_audio_data->channels(); |
| std::vector<float> matrix(kMatrix, kMatrix + array_size); |
| output_audio_data->Mix(*source, matrix); |
| } |
| |
| // "discrete" channel interpretation: up-mix by filling channels until they run |
| // out then zero out remaining channels. Down-mix by filling as many channels as |
| // possible, then dropping remaining channels. |
| // "speakers" channel interpretation: use the below spec. In cases where the |
| // number of channels do not match any of these basic speaker layouts, revert to |
| // "discrete". |
| // Up down mix equations for mono, stereo, quad, 5.1: |
| // https://www.w3.org/TR/webaudio/#ChannelLayouts |
| void MixAudioBuffer(const AudioNode::ChannelInterpretation& interpretation, |
| ShellAudioBus* source, ShellAudioBus* output_audio_data) { |
| DCHECK_GT(source->channels(), 0u); |
| DCHECK_GT(output_audio_data->channels(), 0u); |
| DCHECK(interpretation == AudioNode::kSpeakers || |
| interpretation == AudioNode::kDiscrete) |
| << interpretation; |
| |
| if (output_audio_data->channels() == source->channels()) { |
| output_audio_data->Mix(*source); |
| } else if (source->channels() == 1 && output_audio_data->channels() == 2) { |
| // 1 -> 2: up-mix from mono to stereo. |
| // |
| // output.L = input; |
| // output.R = input; |
| const float kMonoToStereoMatrixSpeaker[] = { |
| 1.0f, // 1.0 * input |
| 1.0f, // 1.0 * input |
| }; |
| |
| const float kMonoToStereoMatrixDiscrete[] = { |
| 1.0f, // 1.0 * input |
| 0.0f, // 0.0 * input |
| }; |
| |
| MixAudioBufferBasedOnInterpretation( |
| kMonoToStereoMatrixSpeaker, kMonoToStereoMatrixDiscrete, interpretation, |
| source, output_audio_data); |
| } else if (source->channels() == 4 && output_audio_data->channels() == 2) { |
| // 4 -> 2: down-mix from quad to stereo. |
| // |
| // output.L = 0.5 * (input.L + input.SL); |
| // output.R = 0.5 * (input.R + input.SR); |
| const float kQuadToStereoMatrixSpeaker[] = { |
| 0.5f, 0.0f, 0.5f, 0.0f, // 0.5 * L + 0.0 * R + 0.5 * SL + 0.0 * SR |
| 0.0f, 0.5f, 0.0f, 0.5f, // 0.0 * L + 0.5 * R + 0.0 * SL + 0.5 * SR |
| }; |
| |
| const float kQuadToStereoMatrixDiscrete[] = { |
| 1.0f, 0.0f, 0.0f, 0.0f, // 1.0 * L + 0.0 * R + 0.0 * SL + 0.0 * SR |
| 0.0f, 1.0f, 0.0f, 0.0f, // 0.0 * L + 1.0 * R + 0.0 * SL + 0.0 * SR |
| }; |
| |
| MixAudioBufferBasedOnInterpretation( |
| kQuadToStereoMatrixSpeaker, kQuadToStereoMatrixDiscrete, interpretation, |
| source, output_audio_data); |
| } else if (source->channels() == 6 && output_audio_data->channels() == 2) { |
| // 5.1 -> 2: down-mix from 5.1 to stereo. |
| // |
| // output.L = L + 0.7071 * (input.C + input.SL) |
| // output.R = R + 0.7071 * (input.C + input.SR) |
| const float kFivePointOneToStereoMatrixSpeaker[] = { |
| // 1.0 * L + 0.0 * R + 0.7071 * C + 0.0 * LFE + 0.7071 * SL + 0.0 * SR |
| 1.0f, 0.0f, 0.7071f, 0.0f, 0.7071f, 0.0f, |
| // 0.0 * L + 1.0 * R + 0.7071 * C + 0.0 * LFE + 0.0 * SL + 0.7071 * SR |
| 0.0f, 1.0f, 0.7071f, 0.0f, 0.0f, 0.7071f, |
| }; |
| |
| const float kFivePointOneToStereoMatrixDiscrete[] = { |
| // 1.0 * L + 0.0 * R + 0.0 * C + 0.0 * LFE + 0.0 * SL + 0.0 * SR |
| 1.f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, |
| // 0.0 * L + 1.0 * R + 0.0 * C + 0.0 * LFE + 0.0 * SL + 0.0 * SR |
| 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, |
| }; |
| |
| MixAudioBufferBasedOnInterpretation( |
| kFivePointOneToStereoMatrixSpeaker, kFivePointOneToStereoMatrixDiscrete, |
| interpretation, source, output_audio_data); |
| } else if (source->channels() == 2 && output_audio_data->channels() == 1) { |
| // 2 -> 1: down-mix from stereo to mono. |
| // |
| // output = 0.5 * (input.L + input.R); |
| const float kStereoToMonoSpeaker[] = { |
| 0.5f, 0.5f, // 0.5 * L + 0.5 * R |
| }; |
| |
| const float kStereoToMonoDiscrete[] = { |
| 1.0f, 0.0f, // 1.0 * L + 0.0 * R |
| }; |
| |
| MixAudioBufferBasedOnInterpretation(kStereoToMonoSpeaker, |
| kStereoToMonoDiscrete, interpretation, |
| source, output_audio_data); |
| } else if (source->channels() == 4 && output_audio_data->channels() == 1) { |
| // 4 -> 1: down-mix from quad to mono. |
| // |
| // output = 0.25 * (input.L + input.R + input.SL + input.SR); |
| const float kQuadToMonoSpeaker[] = { |
| // 0.25 * L + 0.25 * R + 0.25 * SL + 0.25 * SR |
| 0.25f, 0.25f, 0.25f, 0.25f, |
| }; |
| |
| const float kQuadToMonoDiscrete[] = { |
| // 1.0 * L + 0.0 * R + 0.0 * SL + 0.0 * SR |
| 1.0f, 0.0f, 0.0f, 0.0f, |
| }; |
| |
| MixAudioBufferBasedOnInterpretation(kQuadToMonoSpeaker, kQuadToMonoDiscrete, |
| interpretation, source, |
| output_audio_data); |
| } else if (source->channels() == 6 && output_audio_data->channels() == 1) { |
| // 5.1 -> 1: down-mix from 5.1 to mono. |
| // |
| // output = 0.7071 * (input.L + input.R) + input.C + 0.5 * (input.SL + |
| // input.SR) |
| const float kFivePointOneToMonoSpeaker[] = { |
| // 0.7071 * L + 0.7071 * R + 1.0 * C + 0.0 * LFE + 0.5 * SL + 0.5 * SR |
| 0.7071f, 0.7071f, 1.0f, 0.0f, 0.5f, 0.5f, |
| }; |
| |
| const float kFivePointOneToMonoDiscrete[] = { |
| // 1.0 * L + 0.0 * R + 0.0 * C + 0.0 * LFE + 0.0 * SL + 0.0 * SR |
| 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, |
| }; |
| |
| MixAudioBufferBasedOnInterpretation( |
| kFivePointOneToMonoSpeaker, kFivePointOneToMonoDiscrete, interpretation, |
| source, output_audio_data); |
| } else { |
| // TODO: Implement the case which the number of channels do not |
| // match any of those basic speaker layouts. In this case, use "discrete" |
| // channel layout. |
| NOTREACHED() << "The combination of source channels: " << source->channels() |
| << " and output channels: " << output_audio_data->channels() |
| << " is not supported."; |
| } |
| } |
| |
| } // namespace |
| |
| AudioNodeInput::~AudioNodeInput() { |
| owner_node_->audio_lock()->AssertLocked(); |
| |
| DCHECK(outputs_.empty()); |
| } |
| |
| void AudioNodeInput::Connect(AudioNodeOutput* output) { |
| owner_node_->audio_lock()->AssertLocked(); |
| |
| DCHECK(output); |
| |
| // There can only be one connection between a given output of one specific |
| // node and a given input of another specific node. Multiple connections with |
| // the same termini are ignored. |
| if (outputs_.find(output) != outputs_.end()) { |
| return; |
| } |
| |
| output->AddInput(this); |
| outputs_.insert(output); |
| } |
| |
| void AudioNodeInput::Disconnect(AudioNodeOutput* output) { |
| owner_node_->audio_lock()->AssertLocked(); |
| |
| DCHECK(output); |
| |
| if (outputs_.find(output) == outputs_.end()) { |
| NOTREACHED(); |
| return; |
| } |
| |
| outputs_.erase(output); |
| output->RemoveInput(this); |
| } |
| |
| void AudioNodeInput::DisconnectAll() { |
| owner_node_->audio_lock()->AssertLocked(); |
| |
| while (!outputs_.empty()) { |
| AudioNodeOutput* output = *outputs_.begin(); |
| Disconnect(output); |
| } |
| } |
| |
| void AudioNodeInput::FillAudioBus(ShellAudioBus* output_audio_bus, |
| bool* silence) { |
| // This is called by Audio thread. |
| owner_node_->audio_lock()->AssertLocked(); |
| |
| *silence = true; |
| |
| // TODO: Consider computing computedNumberOfChannels and do up-mix or |
| // down-mix base on computedNumberOfChannels. The current implementation |
| // is based on the fact that the channelCountMode is max. |
| DCHECK_EQ(owner_node_->channel_count_mode(), AudioNode::kMax); |
| // Pull audio buffer from connected audio input. When an input is connected |
| // from one or more AudioNode outputs. Fan-in is supported. |
| for (std::set<AudioNodeOutput*>::iterator iter = outputs_.begin(); |
| iter != outputs_.end(); ++iter) { |
| scoped_ptr<ShellAudioBus> audio_bus = (*iter)->PassAudioBusFromSource( |
| static_cast<int32>(output_audio_bus->frames())); |
| |
| if (audio_bus) { |
| MixAudioBuffer(owner_node_->channel_interpretation(), audio_bus.get(), |
| output_audio_bus); |
| *silence = false; |
| } |
| } |
| } |
| |
| } // namespace audio |
| } // namespace cobalt |