b4977de306
Made path from NetEq to AudioTransport ready for many-channel audio. If there is one stream, we can handle anything that fits in an AudioFrame. For many streams, the current limit is 6. Some multi-channel combinations are not supported: e.g. if we get stereo audio and attempt to play out 6 channels. Changes: * AudioFrameOperations - replaced the MonoTo* and *ToMono methods by UpmixChannels & DownmixChannels. * AudioMixer: removed DCHECKs for <= 2 channels and tweaked the mixing algorithm to handle many channels. Bug: webrtc:8649 Change-Id: Ib83e16d463694e35658caa09c27849e853d508fb Reviewed-on: https://webrtc-review.googlesource.com/c/106040 Reviewed-by: Oskar Sundbom <ossu@webrtc.org> Commit-Queue: Alex Loiko <aleloi@webrtc.org> Cr-Commit-Position: refs/heads/master@{#26446}
72 lines
2.5 KiB
C++
72 lines
2.5 KiB
C++
/*
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* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "modules/audio_mixer/audio_frame_manipulator.h"
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#include "audio/utility/audio_frame_operations.h"
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#include "rtc_base/checks.h"
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namespace webrtc {
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uint32_t AudioMixerCalculateEnergy(const AudioFrame& audio_frame) {
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if (audio_frame.muted()) {
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return 0;
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}
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uint32_t energy = 0;
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const int16_t* frame_data = audio_frame.data();
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for (size_t position = 0;
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position < audio_frame.samples_per_channel_ * audio_frame.num_channels_;
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position++) {
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// TODO(aleloi): This can overflow. Convert to floats.
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energy += frame_data[position] * frame_data[position];
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}
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return energy;
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}
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void Ramp(float start_gain, float target_gain, AudioFrame* audio_frame) {
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RTC_DCHECK(audio_frame);
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RTC_DCHECK_GE(start_gain, 0.0f);
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RTC_DCHECK_GE(target_gain, 0.0f);
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if (start_gain == target_gain || audio_frame->muted()) {
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return;
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}
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size_t samples = audio_frame->samples_per_channel_;
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RTC_DCHECK_LT(0, samples);
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float increment = (target_gain - start_gain) / samples;
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float gain = start_gain;
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int16_t* frame_data = audio_frame->mutable_data();
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for (size_t i = 0; i < samples; ++i) {
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// If the audio is interleaved of several channels, we want to
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// apply the same gain change to the ith sample of every channel.
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for (size_t ch = 0; ch < audio_frame->num_channels_; ++ch) {
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frame_data[audio_frame->num_channels_ * i + ch] *= gain;
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}
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gain += increment;
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}
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}
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void RemixFrame(size_t target_number_of_channels, AudioFrame* frame) {
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RTC_DCHECK_GE(target_number_of_channels, 1);
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if (frame->num_channels_ == target_number_of_channels) {
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return;
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}
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if (frame->num_channels_ > target_number_of_channels) {
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AudioFrameOperations::DownmixChannels(target_number_of_channels, frame);
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} else if (frame->num_channels_ < target_number_of_channels) {
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AudioFrameOperations::UpmixChannels(target_number_of_channels, frame);
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}
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RTC_DCHECK_EQ(frame->num_channels_, target_number_of_channels)
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<< "Wrong number of channels, " << frame->num_channels_ << " vs "
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<< target_number_of_channels;
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}
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} // namespace webrtc
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