| /* |
| * Copyright (C) 2010 Google Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of |
| * its contributors may be used to endorse or promote products derived |
| * from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY |
| * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "platform/audio/AudioBus.h" |
| |
| #include <assert.h> |
| #include <math.h> |
| #include <algorithm> |
| #include <memory> |
| #include "platform/SharedBuffer.h" |
| #include "platform/audio/AudioFileReader.h" |
| #include "platform/audio/DenormalDisabler.h" |
| #include "platform/audio/SincResampler.h" |
| #include "platform/audio/VectorMath.h" |
| #include "public/platform/Platform.h" |
| #include "public/platform/WebAudioBus.h" |
| |
| namespace blink { |
| |
| using namespace VectorMath; |
| |
| const unsigned kMaxBusChannels = 32; |
| |
| scoped_refptr<AudioBus> AudioBus::Create(unsigned number_of_channels, |
| size_t length, |
| bool allocate) { |
| DCHECK_LE(number_of_channels, kMaxBusChannels); |
| if (number_of_channels > kMaxBusChannels) |
| return nullptr; |
| |
| return base::AdoptRef(new AudioBus(number_of_channels, length, allocate)); |
| } |
| |
| AudioBus::AudioBus(unsigned number_of_channels, size_t length, bool allocate) |
| : length_(length), sample_rate_(0) { |
| channels_.ReserveInitialCapacity(number_of_channels); |
| |
| for (unsigned i = 0; i < number_of_channels; ++i) { |
| std::unique_ptr<AudioChannel> channel = |
| allocate ? WTF::WrapUnique(new AudioChannel(length)) |
| : WTF::WrapUnique(new AudioChannel(nullptr, length)); |
| channels_.push_back(std::move(channel)); |
| } |
| |
| layout_ = kLayoutCanonical; // for now this is the only layout we define |
| } |
| |
| void AudioBus::SetChannelMemory(unsigned channel_index, |
| float* storage, |
| size_t length) { |
| if (channel_index < channels_.size()) { |
| Channel(channel_index)->Set(storage, length); |
| // FIXME: verify that this length matches all the other channel lengths |
| length_ = length; |
| } |
| } |
| |
| void AudioBus::ResizeSmaller(size_t new_length) { |
| DCHECK_LE(new_length, length_); |
| if (new_length <= length_) |
| length_ = new_length; |
| |
| for (unsigned i = 0; i < channels_.size(); ++i) |
| channels_[i]->ResizeSmaller(new_length); |
| } |
| |
| void AudioBus::Zero() { |
| for (unsigned i = 0; i < channels_.size(); ++i) |
| channels_[i]->Zero(); |
| } |
| |
| AudioChannel* AudioBus::ChannelByType(unsigned channel_type) { |
| // For now we only support canonical channel layouts... |
| if (layout_ != kLayoutCanonical) |
| return nullptr; |
| |
| switch (NumberOfChannels()) { |
| case 1: // mono |
| if (channel_type == kChannelMono || channel_type == kChannelLeft) |
| return Channel(0); |
| return nullptr; |
| |
| case 2: // stereo |
| switch (channel_type) { |
| case kChannelLeft: |
| return Channel(0); |
| case kChannelRight: |
| return Channel(1); |
| default: |
| return nullptr; |
| } |
| |
| case 4: // quad |
| switch (channel_type) { |
| case kChannelLeft: |
| return Channel(0); |
| case kChannelRight: |
| return Channel(1); |
| case kChannelSurroundLeft: |
| return Channel(2); |
| case kChannelSurroundRight: |
| return Channel(3); |
| default: |
| return nullptr; |
| } |
| |
| case 5: // 5.0 |
| switch (channel_type) { |
| case kChannelLeft: |
| return Channel(0); |
| case kChannelRight: |
| return Channel(1); |
| case kChannelCenter: |
| return Channel(2); |
| case kChannelSurroundLeft: |
| return Channel(3); |
| case kChannelSurroundRight: |
| return Channel(4); |
| default: |
| return nullptr; |
| } |
| |
| case 6: // 5.1 |
| switch (channel_type) { |
| case kChannelLeft: |
| return Channel(0); |
| case kChannelRight: |
| return Channel(1); |
| case kChannelCenter: |
| return Channel(2); |
| case kChannelLFE: |
| return Channel(3); |
| case kChannelSurroundLeft: |
| return Channel(4); |
| case kChannelSurroundRight: |
| return Channel(5); |
| default: |
| return nullptr; |
| } |
| } |
| |
| NOTREACHED(); |
| return nullptr; |
| } |
| |
| const AudioChannel* AudioBus::ChannelByType(unsigned type) const { |
| return const_cast<AudioBus*>(this)->ChannelByType(type); |
| } |
| |
| // Returns true if the channel count and frame-size match. |
| bool AudioBus::TopologyMatches(const AudioBus& bus) const { |
| if (NumberOfChannels() != bus.NumberOfChannels()) |
| return false; // channel mismatch |
| |
| // Make sure source bus has enough frames. |
| if (length() > bus.length()) |
| return false; // frame-size mismatch |
| |
| return true; |
| } |
| |
| scoped_refptr<AudioBus> AudioBus::CreateBufferFromRange( |
| const AudioBus* source_buffer, |
| unsigned start_frame, |
| unsigned end_frame) { |
| size_t number_of_source_frames = source_buffer->length(); |
| unsigned number_of_channels = source_buffer->NumberOfChannels(); |
| |
| // Sanity checking |
| bool is_range_safe = |
| start_frame < end_frame && end_frame <= number_of_source_frames; |
| DCHECK(is_range_safe); |
| if (!is_range_safe) |
| return nullptr; |
| |
| size_t range_length = end_frame - start_frame; |
| |
| scoped_refptr<AudioBus> audio_bus = Create(number_of_channels, range_length); |
| audio_bus->SetSampleRate(source_buffer->SampleRate()); |
| |
| for (unsigned i = 0; i < number_of_channels; ++i) |
| audio_bus->Channel(i)->CopyFromRange(source_buffer->Channel(i), start_frame, |
| end_frame); |
| |
| return audio_bus; |
| } |
| |
| float AudioBus::MaxAbsValue() const { |
| float max = 0.0f; |
| for (unsigned i = 0; i < NumberOfChannels(); ++i) { |
| const AudioChannel* channel = this->Channel(i); |
| max = std::max(max, channel->MaxAbsValue()); |
| } |
| |
| return max; |
| } |
| |
| void AudioBus::Normalize() { |
| float max = MaxAbsValue(); |
| if (max) |
| Scale(1.0f / max); |
| } |
| |
| void AudioBus::Scale(float scale) { |
| for (unsigned i = 0; i < NumberOfChannels(); ++i) |
| Channel(i)->Scale(scale); |
| } |
| |
| void AudioBus::CopyFrom(const AudioBus& source_bus, |
| ChannelInterpretation channel_interpretation) { |
| if (&source_bus == this) |
| return; |
| |
| // Copying bus is equivalent to zeroing and then summing. |
| Zero(); |
| SumFrom(source_bus, channel_interpretation); |
| } |
| |
| void AudioBus::SumFrom(const AudioBus& source_bus, |
| ChannelInterpretation channel_interpretation) { |
| if (&source_bus == this) |
| return; |
| |
| unsigned number_of_source_channels = source_bus.NumberOfChannels(); |
| unsigned number_of_destination_channels = NumberOfChannels(); |
| |
| // If the channel numbers are equal, perform channels-wise summing. |
| if (number_of_source_channels == number_of_destination_channels) { |
| for (unsigned i = 0; i < number_of_source_channels; ++i) |
| Channel(i)->SumFrom(source_bus.Channel(i)); |
| |
| return; |
| } |
| |
| // Otherwise perform up/down-mix or the discrete transfer based on the |
| // number of channels and the channel interpretation. |
| switch (channel_interpretation) { |
| case kSpeakers: |
| if (number_of_source_channels < number_of_destination_channels) |
| SumFromByUpMixing(source_bus); |
| else |
| SumFromByDownMixing(source_bus); |
| break; |
| case kDiscrete: |
| DiscreteSumFrom(source_bus); |
| break; |
| } |
| } |
| |
| void AudioBus::DiscreteSumFrom(const AudioBus& source_bus) { |
| unsigned number_of_source_channels = source_bus.NumberOfChannels(); |
| unsigned number_of_destination_channels = NumberOfChannels(); |
| |
| if (number_of_destination_channels < number_of_source_channels) { |
| // Down-mix by summing channels and dropping the remaining. |
| for (unsigned i = 0; i < number_of_destination_channels; ++i) |
| Channel(i)->SumFrom(source_bus.Channel(i)); |
| } else if (number_of_destination_channels > number_of_source_channels) { |
| // Up-mix by summing as many channels as we have. |
| for (unsigned i = 0; i < number_of_source_channels; ++i) |
| Channel(i)->SumFrom(source_bus.Channel(i)); |
| } |
| } |
| |
| void AudioBus::SumFromByUpMixing(const AudioBus& source_bus) { |
| unsigned number_of_source_channels = source_bus.NumberOfChannels(); |
| unsigned number_of_destination_channels = NumberOfChannels(); |
| |
| if ((number_of_source_channels == 1 && number_of_destination_channels == 2) || |
| (number_of_source_channels == 1 && number_of_destination_channels == 4)) { |
| // Up-mixing: 1 -> 2, 1 -> 4 |
| // output.L = input |
| // output.R = input |
| // output.SL = 0 (in the case of 1 -> 4) |
| // output.SR = 0 (in the case of 1 -> 4) |
| const AudioChannel* source_l = source_bus.ChannelByType(kChannelLeft); |
| ChannelByType(kChannelLeft)->SumFrom(source_l); |
| ChannelByType(kChannelRight)->SumFrom(source_l); |
| } else if (number_of_source_channels == 1 && |
| number_of_destination_channels == 6) { |
| // Up-mixing: 1 -> 5.1 |
| // output.L = 0 |
| // output.R = 0 |
| // output.C = input (put in center channel) |
| // output.LFE = 0 |
| // output.SL = 0 |
| // output.SR = 0 |
| ChannelByType(kChannelCenter) |
| ->SumFrom(source_bus.ChannelByType(kChannelLeft)); |
| } else if ((number_of_source_channels == 2 && |
| number_of_destination_channels == 4) || |
| (number_of_source_channels == 2 && |
| number_of_destination_channels == 6)) { |
| // Up-mixing: 2 -> 4, 2 -> 5.1 |
| // output.L = input.L |
| // output.R = input.R |
| // output.C = 0 (in the case of 2 -> 5.1) |
| // output.LFE = 0 (in the case of 2 -> 5.1) |
| // output.SL = 0 |
| // output.SR = 0 |
| ChannelByType(kChannelLeft) |
| ->SumFrom(source_bus.ChannelByType(kChannelLeft)); |
| ChannelByType(kChannelRight) |
| ->SumFrom(source_bus.ChannelByType(kChannelRight)); |
| } else if (number_of_source_channels == 4 && |
| number_of_destination_channels == 6) { |
| // Up-mixing: 4 -> 5.1 |
| // output.L = input.L |
| // output.R = input.R |
| // output.C = 0 |
| // output.LFE = 0 |
| // output.SL = input.SL |
| // output.SR = input.SR |
| ChannelByType(kChannelLeft) |
| ->SumFrom(source_bus.ChannelByType(kChannelLeft)); |
| ChannelByType(kChannelRight) |
| ->SumFrom(source_bus.ChannelByType(kChannelRight)); |
| ChannelByType(kChannelSurroundLeft) |
| ->SumFrom(source_bus.ChannelByType(kChannelSurroundLeft)); |
| ChannelByType(kChannelSurroundRight) |
| ->SumFrom(source_bus.ChannelByType(kChannelSurroundRight)); |
| } else { |
| // All other cases, fall back to the discrete sum. This will silence the |
| // excessive channels. |
| DiscreteSumFrom(source_bus); |
| } |
| } |
| |
| void AudioBus::SumFromByDownMixing(const AudioBus& source_bus) { |
| unsigned number_of_source_channels = source_bus.NumberOfChannels(); |
| unsigned number_of_destination_channels = NumberOfChannels(); |
| |
| if (number_of_source_channels == 2 && number_of_destination_channels == 1) { |
| // Down-mixing: 2 -> 1 |
| // output = 0.5 * (input.L + input.R) |
| const float* source_l = source_bus.ChannelByType(kChannelLeft)->Data(); |
| const float* source_r = source_bus.ChannelByType(kChannelRight)->Data(); |
| |
| float* destination = ChannelByType(kChannelLeft)->MutableData(); |
| float scale = 0.5; |
| |
| Vsma(source_l, 1, &scale, destination, 1, length()); |
| Vsma(source_r, 1, &scale, destination, 1, length()); |
| } else if (number_of_source_channels == 4 && |
| number_of_destination_channels == 1) { |
| // Down-mixing: 4 -> 1 |
| // output = 0.25 * (input.L + input.R + input.SL + input.SR) |
| const float* source_l = source_bus.ChannelByType(kChannelLeft)->Data(); |
| const float* source_r = source_bus.ChannelByType(kChannelRight)->Data(); |
| const float* source_sl = |
| source_bus.ChannelByType(kChannelSurroundLeft)->Data(); |
| const float* source_sr = |
| source_bus.ChannelByType(kChannelSurroundRight)->Data(); |
| |
| float* destination = ChannelByType(kChannelLeft)->MutableData(); |
| float scale = 0.25; |
| |
| Vsma(source_l, 1, &scale, destination, 1, length()); |
| Vsma(source_r, 1, &scale, destination, 1, length()); |
| Vsma(source_sl, 1, &scale, destination, 1, length()); |
| Vsma(source_sr, 1, &scale, destination, 1, length()); |
| } else if (number_of_source_channels == 6 && |
| number_of_destination_channels == 1) { |
| // Down-mixing: 5.1 -> 1 |
| // output = sqrt(1/2) * (input.L + input.R) + input.C |
| // + 0.5 * (input.SL + input.SR) |
| const float* source_l = source_bus.ChannelByType(kChannelLeft)->Data(); |
| const float* source_r = source_bus.ChannelByType(kChannelRight)->Data(); |
| const float* source_c = source_bus.ChannelByType(kChannelCenter)->Data(); |
| const float* source_sl = |
| source_bus.ChannelByType(kChannelSurroundLeft)->Data(); |
| const float* source_sr = |
| source_bus.ChannelByType(kChannelSurroundRight)->Data(); |
| |
| float* destination = ChannelByType(kChannelLeft)->MutableData(); |
| float scale_sqrt_half = sqrtf(0.5); |
| float scale_half = 0.5; |
| |
| Vsma(source_l, 1, &scale_sqrt_half, destination, 1, length()); |
| Vsma(source_r, 1, &scale_sqrt_half, destination, 1, length()); |
| Vadd(source_c, 1, destination, 1, destination, 1, length()); |
| Vsma(source_sl, 1, &scale_half, destination, 1, length()); |
| Vsma(source_sr, 1, &scale_half, destination, 1, length()); |
| } else if (number_of_source_channels == 4 && |
| number_of_destination_channels == 2) { |
| // Down-mixing: 4 -> 2 |
| // output.L = 0.5 * (input.L + input.SL) |
| // output.R = 0.5 * (input.R + input.SR) |
| const float* source_l = source_bus.ChannelByType(kChannelLeft)->Data(); |
| const float* source_r = source_bus.ChannelByType(kChannelRight)->Data(); |
| const float* source_sl = |
| source_bus.ChannelByType(kChannelSurroundLeft)->Data(); |
| const float* source_sr = |
| source_bus.ChannelByType(kChannelSurroundRight)->Data(); |
| |
| float* destination_l = ChannelByType(kChannelLeft)->MutableData(); |
| float* destination_r = ChannelByType(kChannelRight)->MutableData(); |
| float scale_half = 0.5; |
| |
| Vsma(source_l, 1, &scale_half, destination_l, 1, length()); |
| Vsma(source_sl, 1, &scale_half, destination_l, 1, length()); |
| Vsma(source_r, 1, &scale_half, destination_r, 1, length()); |
| Vsma(source_sr, 1, &scale_half, destination_r, 1, length()); |
| } else if (number_of_source_channels == 6 && |
| number_of_destination_channels == 2) { |
| // Down-mixing: 5.1 -> 2 |
| // output.L = input.L + sqrt(1/2) * (input.C + input.SL) |
| // output.R = input.R + sqrt(1/2) * (input.C + input.SR) |
| const float* source_l = source_bus.ChannelByType(kChannelLeft)->Data(); |
| const float* source_r = source_bus.ChannelByType(kChannelRight)->Data(); |
| const float* source_c = source_bus.ChannelByType(kChannelCenter)->Data(); |
| const float* source_sl = |
| source_bus.ChannelByType(kChannelSurroundLeft)->Data(); |
| const float* source_sr = |
| source_bus.ChannelByType(kChannelSurroundRight)->Data(); |
| |
| float* destination_l = ChannelByType(kChannelLeft)->MutableData(); |
| float* destination_r = ChannelByType(kChannelRight)->MutableData(); |
| float scale_sqrt_half = sqrtf(0.5); |
| |
| Vadd(source_l, 1, destination_l, 1, destination_l, 1, length()); |
| Vsma(source_c, 1, &scale_sqrt_half, destination_l, 1, length()); |
| Vsma(source_sl, 1, &scale_sqrt_half, destination_l, 1, length()); |
| Vadd(source_r, 1, destination_r, 1, destination_r, 1, length()); |
| Vsma(source_c, 1, &scale_sqrt_half, destination_r, 1, length()); |
| Vsma(source_sr, 1, &scale_sqrt_half, destination_r, 1, length()); |
| } else if (number_of_source_channels == 6 && |
| number_of_destination_channels == 4) { |
| // Down-mixing: 5.1 -> 4 |
| // output.L = input.L + sqrt(1/2) * input.C |
| // output.R = input.R + sqrt(1/2) * input.C |
| // output.SL = input.SL |
| // output.SR = input.SR |
| const float* source_l = source_bus.ChannelByType(kChannelLeft)->Data(); |
| const float* source_r = source_bus.ChannelByType(kChannelRight)->Data(); |
| const float* source_c = source_bus.ChannelByType(kChannelCenter)->Data(); |
| |
| float* destination_l = ChannelByType(kChannelLeft)->MutableData(); |
| float* destination_r = ChannelByType(kChannelRight)->MutableData(); |
| float scale_sqrt_half = sqrtf(0.5); |
| |
| Vadd(source_l, 1, destination_l, 1, destination_l, 1, length()); |
| Vsma(source_c, 1, &scale_sqrt_half, destination_l, 1, length()); |
| Vadd(source_r, 1, destination_r, 1, destination_r, 1, length()); |
| Vsma(source_c, 1, &scale_sqrt_half, destination_r, 1, length()); |
| Channel(2)->SumFrom(source_bus.Channel(4)); |
| Channel(3)->SumFrom(source_bus.Channel(5)); |
| } else { |
| // All other cases, fall back to the discrete sum. This will perform |
| // channel-wise sum until the destination channels run out. |
| DiscreteSumFrom(source_bus); |
| } |
| } |
| |
| void AudioBus::CopyWithGainFrom(const AudioBus& source_bus, float gain) { |
| if (!TopologyMatches(source_bus)) { |
| NOTREACHED(); |
| Zero(); |
| return; |
| } |
| |
| if (source_bus.IsSilent()) { |
| Zero(); |
| return; |
| } |
| |
| unsigned number_of_channels = this->NumberOfChannels(); |
| DCHECK_LE(number_of_channels, kMaxBusChannels); |
| if (number_of_channels > kMaxBusChannels) |
| return; |
| |
| // If it is copying from the same bus and no need to change gain, just return. |
| if (this == &source_bus && gain == 1) |
| return; |
| |
| AudioBus& source_bus_safe = const_cast<AudioBus&>(source_bus); |
| const float* sources[kMaxBusChannels]; |
| float* destinations[kMaxBusChannels]; |
| |
| for (unsigned i = 0; i < number_of_channels; ++i) { |
| sources[i] = source_bus_safe.Channel(i)->Data(); |
| destinations[i] = Channel(i)->MutableData(); |
| } |
| |
| unsigned frames_to_process = length(); |
| |
| // Handle gains of 0 and 1 (exactly) specially. |
| if (gain == 1) { |
| for (unsigned channel_index = 0; channel_index < number_of_channels; |
| ++channel_index) { |
| memcpy(destinations[channel_index], sources[channel_index], |
| frames_to_process * sizeof(*destinations[channel_index])); |
| } |
| } else if (gain == 0) { |
| for (unsigned channel_index = 0; channel_index < number_of_channels; |
| ++channel_index) { |
| memset(destinations[channel_index], 0, |
| frames_to_process * sizeof(*destinations[channel_index])); |
| } |
| } else { |
| for (unsigned channel_index = 0; channel_index < number_of_channels; |
| ++channel_index) { |
| Vsmul(sources[channel_index], 1, &gain, destinations[channel_index], 1, |
| frames_to_process); |
| } |
| } |
| } |
| |
| void AudioBus::CopyWithSampleAccurateGainValuesFrom( |
| const AudioBus& source_bus, |
| float* gain_values, |
| unsigned number_of_gain_values) { |
| // Make sure we're processing from the same type of bus. |
| // We *are* able to process from mono -> stereo |
| if (source_bus.NumberOfChannels() != 1 && !TopologyMatches(source_bus)) { |
| NOTREACHED(); |
| return; |
| } |
| |
| if (!gain_values || number_of_gain_values > source_bus.length()) { |
| NOTREACHED(); |
| return; |
| } |
| |
| if (source_bus.length() == number_of_gain_values && |
| source_bus.length() == length() && source_bus.IsSilent()) { |
| Zero(); |
| return; |
| } |
| |
| // We handle both the 1 -> N and N -> N case here. |
| const float* source = source_bus.Channel(0)->Data(); |
| for (unsigned channel_index = 0; channel_index < NumberOfChannels(); |
| ++channel_index) { |
| if (source_bus.NumberOfChannels() == NumberOfChannels()) |
| source = source_bus.Channel(channel_index)->Data(); |
| float* destination = Channel(channel_index)->MutableData(); |
| Vmul(source, 1, gain_values, 1, destination, 1, number_of_gain_values); |
| } |
| } |
| |
| scoped_refptr<AudioBus> AudioBus::CreateBySampleRateConverting( |
| const AudioBus* source_bus, |
| bool mix_to_mono, |
| double new_sample_rate) { |
| // sourceBus's sample-rate must be known. |
| DCHECK(source_bus); |
| DCHECK(source_bus->SampleRate()); |
| if (!source_bus || !source_bus->SampleRate()) |
| return nullptr; |
| |
| double source_sample_rate = source_bus->SampleRate(); |
| double destination_sample_rate = new_sample_rate; |
| double sample_rate_ratio = source_sample_rate / destination_sample_rate; |
| unsigned number_of_source_channels = source_bus->NumberOfChannels(); |
| |
| if (number_of_source_channels == 1) |
| mix_to_mono = false; // already mono |
| |
| if (source_sample_rate == destination_sample_rate) { |
| // No sample-rate conversion is necessary. |
| if (mix_to_mono) |
| return AudioBus::CreateByMixingToMono(source_bus); |
| |
| // Return exact copy. |
| return AudioBus::CreateBufferFromRange(source_bus, 0, source_bus->length()); |
| } |
| |
| if (source_bus->IsSilent()) { |
| scoped_refptr<AudioBus> silent_bus = Create( |
| number_of_source_channels, source_bus->length() / sample_rate_ratio); |
| silent_bus->SetSampleRate(new_sample_rate); |
| return silent_bus; |
| } |
| |
| // First, mix to mono (if necessary) then sample-rate convert. |
| const AudioBus* resampler_source_bus; |
| scoped_refptr<AudioBus> mixed_mono_bus; |
| if (mix_to_mono) { |
| mixed_mono_bus = AudioBus::CreateByMixingToMono(source_bus); |
| resampler_source_bus = mixed_mono_bus.get(); |
| } else { |
| // Directly resample without down-mixing. |
| resampler_source_bus = source_bus; |
| } |
| |
| // Calculate destination length based on the sample-rates. |
| int source_length = resampler_source_bus->length(); |
| int destination_length = source_length / sample_rate_ratio; |
| |
| // Create destination bus with same number of channels. |
| unsigned number_of_destination_channels = |
| resampler_source_bus->NumberOfChannels(); |
| scoped_refptr<AudioBus> destination_bus = |
| Create(number_of_destination_channels, destination_length); |
| |
| // Sample-rate convert each channel. |
| for (unsigned i = 0; i < number_of_destination_channels; ++i) { |
| const float* source = resampler_source_bus->Channel(i)->Data(); |
| float* destination = destination_bus->Channel(i)->MutableData(); |
| |
| SincResampler resampler(sample_rate_ratio); |
| resampler.Process(source, destination, source_length); |
| } |
| |
| destination_bus->ClearSilentFlag(); |
| destination_bus->SetSampleRate(new_sample_rate); |
| return destination_bus; |
| } |
| |
| scoped_refptr<AudioBus> AudioBus::CreateByMixingToMono( |
| const AudioBus* source_bus) { |
| if (source_bus->IsSilent()) |
| return Create(1, source_bus->length()); |
| |
| switch (source_bus->NumberOfChannels()) { |
| case 1: |
| // Simply create an exact copy. |
| return AudioBus::CreateBufferFromRange(source_bus, 0, |
| source_bus->length()); |
| case 2: { |
| unsigned n = source_bus->length(); |
| scoped_refptr<AudioBus> destination_bus = Create(1, n); |
| |
| const float* source_l = source_bus->Channel(0)->Data(); |
| const float* source_r = source_bus->Channel(1)->Data(); |
| float* destination = destination_bus->Channel(0)->MutableData(); |
| |
| // Do the mono mixdown. |
| for (unsigned i = 0; i < n; ++i) |
| destination[i] = (source_l[i] + source_r[i]) / 2; |
| |
| destination_bus->ClearSilentFlag(); |
| destination_bus->SetSampleRate(source_bus->SampleRate()); |
| return destination_bus; |
| } |
| } |
| |
| NOTREACHED(); |
| return nullptr; |
| } |
| |
| bool AudioBus::IsSilent() const { |
| for (size_t i = 0; i < channels_.size(); ++i) { |
| if (!channels_[i]->IsSilent()) |
| return false; |
| } |
| return true; |
| } |
| |
| void AudioBus::ClearSilentFlag() { |
| for (size_t i = 0; i < channels_.size(); ++i) |
| channels_[i]->ClearSilentFlag(); |
| } |
| |
| scoped_refptr<AudioBus> DecodeAudioFileData(const char* data, size_t size) { |
| WebAudioBus web_audio_bus; |
| if (Platform::Current()->DecodeAudioFileData(&web_audio_bus, data, size)) |
| return web_audio_bus.Release(); |
| return nullptr; |
| } |
| |
| scoped_refptr<AudioBus> AudioBus::GetDataResource(const char* name, |
| float sample_rate) { |
| const WebData& resource = Platform::Current()->GetDataResource(name); |
| if (resource.IsEmpty()) |
| return nullptr; |
| |
| // Currently, the only client of this method is caching the result -- so |
| // it's reasonable to (potentially) pay a one-time flat access cost. |
| // If this becomes problematic, we'll have the refactor DecodeAudioFileData |
| // to take WebData and use segmented access. |
| SharedBuffer::DeprecatedFlatData flat_data( |
| resource.operator scoped_refptr<SharedBuffer>()); |
| scoped_refptr<AudioBus> audio_bus = |
| DecodeAudioFileData(flat_data.Data(), flat_data.size()); |
| |
| if (!audio_bus.get()) |
| return nullptr; |
| |
| // If the bus is already at the requested sample-rate then return as is. |
| if (audio_bus->SampleRate() == sample_rate) |
| return audio_bus; |
| |
| return AudioBus::CreateBySampleRateConverting(audio_bus.get(), false, |
| sample_rate); |
| } |
| |
| scoped_refptr<AudioBus> CreateBusFromInMemoryAudioFile(const void* data, |
| size_t data_size, |
| bool mix_to_mono, |
| float sample_rate) { |
| scoped_refptr<AudioBus> audio_bus = |
| DecodeAudioFileData(static_cast<const char*>(data), data_size); |
| if (!audio_bus.get()) |
| return nullptr; |
| |
| // If the bus needs no conversion then return as is. |
| if ((!mix_to_mono || audio_bus->NumberOfChannels() == 1) && |
| audio_bus->SampleRate() == sample_rate) |
| return audio_bus; |
| |
| return AudioBus::CreateBySampleRateConverting(audio_bus.get(), mix_to_mono, |
| sample_rate); |
| } |
| |
| } // namespace blink |
