298 lines
11 KiB
Objective-C
298 lines
11 KiB
Objective-C
//
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// Downmix.m
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// Cog
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//
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// Created by Christopher Snowhill on 2/05/22.
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// Copyright 2022 __LoSnoCo__. All rights reserved.
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//
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#import "Downmix.h"
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#import "Logging.h"
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#import "AudioChunk.h"
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#import <Accelerate/Accelerate.h>
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static void downmix_to_stereo(const float *inBuffer, int channels, uint32_t config, float *outBuffer, size_t count) {
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float FrontRatios[2] = { 0.0F, 0.0F };
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float FrontCenterRatio = 0.0F;
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float LFERatio = 0.0F;
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float BackRatios[2] = { 0.0F, 0.0F };
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float BackCenterRatio = 0.0F;
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float SideRatios[2] = { 0.0F, 0.0F };
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if(config & (AudioChannelFrontLeft | AudioChannelFrontRight)) {
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FrontRatios[0] = 1.0F;
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}
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if(config & AudioChannelFrontCenter) {
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FrontRatios[0] = 0.5858F;
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FrontCenterRatio = 0.4142F;
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}
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if(config & (AudioChannelBackLeft | AudioChannelBackRight)) {
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if(config & AudioChannelFrontCenter) {
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FrontRatios[0] = 0.651F;
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FrontCenterRatio = 0.46F;
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BackRatios[0] = 0.5636F;
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BackRatios[1] = 0.3254F;
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} else {
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FrontRatios[0] = 0.4226F;
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BackRatios[0] = 0.366F;
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BackRatios[1] = 0.2114F;
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}
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}
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if(config & AudioChannelLFE) {
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FrontRatios[0] *= 0.8F;
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FrontCenterRatio *= 0.8F;
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LFERatio = FrontCenterRatio;
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BackRatios[0] *= 0.8F;
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BackRatios[1] *= 0.8F;
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}
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if(config & AudioChannelBackCenter) {
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FrontRatios[0] *= 0.86F;
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FrontCenterRatio *= 0.86F;
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LFERatio *= 0.86F;
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BackRatios[0] *= 0.86F;
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BackRatios[1] *= 0.86F;
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BackCenterRatio = FrontCenterRatio * 0.86F;
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}
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if(config & (AudioChannelSideLeft | AudioChannelSideRight)) {
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float ratio = 0.73F;
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if(config & AudioChannelBackCenter) ratio = 0.85F;
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FrontRatios[0] *= ratio;
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FrontCenterRatio *= ratio;
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LFERatio *= ratio;
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BackRatios[0] *= ratio;
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BackRatios[1] *= ratio;
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BackCenterRatio *= ratio;
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SideRatios[0] = 0.463882352941176 * ratio;
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SideRatios[1] = 0.267882352941176 * ratio;
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}
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int32_t channelIndexes[channels];
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for(int i = 0; i < channels; ++i) {
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channelIndexes[i] = [AudioChunk findChannelIndex:[AudioChunk extractChannelFlag:i fromConfig:config]];
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}
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vDSP_vclr(outBuffer, 1, count * 2);
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float tempBuffer[count * 2];
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for(uint32_t i = 0; i < channels; ++i) {
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float leftRatio = 0.0F;
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float rightRatio = 0.0F;
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switch(channelIndexes[i]) {
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case 0:
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leftRatio = FrontRatios[0];
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rightRatio = FrontRatios[1];
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break;
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case 1:
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leftRatio = FrontRatios[1];
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rightRatio = FrontRatios[0];
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break;
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case 2:
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leftRatio = FrontCenterRatio;
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rightRatio = FrontCenterRatio;
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break;
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case 3:
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leftRatio = LFERatio;
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rightRatio = LFERatio;
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break;
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case 4:
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leftRatio = BackRatios[0];
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rightRatio = BackRatios[1];
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break;
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case 5:
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leftRatio = BackRatios[1];
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rightRatio = BackRatios[0];
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break;
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case 6:
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case 7:
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break;
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case 8:
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leftRatio = BackCenterRatio;
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rightRatio = BackCenterRatio;
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break;
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case 9:
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leftRatio = SideRatios[0];
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rightRatio = SideRatios[1];
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break;
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case 10:
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leftRatio = SideRatios[1];
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rightRatio = SideRatios[0];
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break;
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case 11:
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case 12:
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case 13:
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case 14:
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case 15:
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case 16:
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case 17:
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default:
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break;
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}
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vDSP_vsmul(inBuffer + i, channels, &leftRatio, tempBuffer, 1, count);
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vDSP_vsmul(inBuffer + i, channels, &rightRatio, tempBuffer + count, 1, count);
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vDSP_vadd(outBuffer, 2, tempBuffer, 1, outBuffer, 2, count);
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vDSP_vadd(outBuffer + 1, 2, tempBuffer + count, 1, outBuffer + 1, 2, count);
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}
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}
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static void downmix_to_mono(const float *inBuffer, int channels, uint32_t config, float *outBuffer, size_t count) {
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float tempBuffer[count * 2];
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if(channels > 2 || config != AudioConfigStereo) {
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downmix_to_stereo(inBuffer, channels, config, tempBuffer, count);
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inBuffer = tempBuffer;
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channels = 2;
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config = AudioConfigStereo;
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}
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cblas_scopy((int)count, inBuffer, 2, outBuffer, 1);
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vDSP_vadd(outBuffer, 1, inBuffer + 1, 2, outBuffer, 1, count);
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}
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static void upmix(const float *inBuffer, int inchannels, uint32_t inconfig, float *outBuffer, int outchannels, uint32_t outconfig, size_t count) {
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if(inconfig == AudioConfigMono && outconfig == AudioConfigStereo) {
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cblas_scopy((int)count, inBuffer, 1, outBuffer, 2);
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cblas_scopy((int)count, inBuffer, 1, outBuffer + 1, 2);
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} else if(inconfig == AudioConfigMono && outconfig == AudioConfig4Point0) {
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cblas_scopy((int)count, inBuffer, 1, outBuffer, 4);
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cblas_scopy((int)count, inBuffer, 1, outBuffer + 1, 4);
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vDSP_vclr(outBuffer + 2, 4, count);
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vDSP_vclr(outBuffer + 3, 4, count);
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} else if(inconfig == AudioConfigMono && (outconfig & AudioChannelFrontCenter)) {
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uint32_t cIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelFrontCenter];
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cblas_scopy((int)count, inBuffer, 1, outBuffer + cIndex, outchannels);
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for(size_t i = 0; i < cIndex; ++i) {
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vDSP_vclr(outBuffer + i, outchannels, (int)count);
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}
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for(size_t i = cIndex + 1; i < outchannels; ++i) {
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vDSP_vclr(outBuffer + i, outchannels, (int)count);
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}
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} else if(inconfig == AudioConfig4Point0 && outchannels >= 5) {
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uint32_t flIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelFrontLeft];
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uint32_t frIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelFrontRight];
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uint32_t blIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelBackLeft];
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uint32_t brIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelBackRight];
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vDSP_vclr(outBuffer, 1, count * outchannels);
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if(flIndex != ~0)
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cblas_scopy((int)count, inBuffer + 0, 4, outBuffer + flIndex, outchannels);
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if(frIndex != ~0)
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cblas_scopy((int)count, inBuffer + 1, 4, outBuffer + frIndex, outchannels);
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if(blIndex != ~0)
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cblas_scopy((int)count, inBuffer + 2, 4, outBuffer + blIndex, outchannels);
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if(brIndex != ~0)
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cblas_scopy((int)count, inBuffer + 3, 4, outBuffer + brIndex, outchannels);
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} else if(inconfig == AudioConfig5Point0 && outchannels >= 6) {
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uint32_t flIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelFrontLeft];
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uint32_t frIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelFrontRight];
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uint32_t cIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelFrontCenter];
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uint32_t blIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelBackLeft];
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uint32_t brIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelBackRight];
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vDSP_vclr(outBuffer, 1, count * outchannels);
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if(flIndex != ~0)
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cblas_scopy((int)count, inBuffer + 0, 5, outBuffer + flIndex, outchannels);
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if(frIndex != ~0)
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cblas_scopy((int)count, inBuffer + 1, 5, outBuffer + frIndex, outchannels);
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if(cIndex != ~0)
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cblas_scopy((int)count, inBuffer + 2, 5, outBuffer + cIndex, outchannels);
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if(blIndex != ~0)
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cblas_scopy((int)count, inBuffer + 3, 5, outBuffer + blIndex, outchannels);
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if(brIndex != ~0)
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cblas_scopy((int)count, inBuffer + 4, 5, outBuffer + brIndex, outchannels);
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} else if(inconfig == AudioConfig6Point1 && outchannels >= 8) {
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uint32_t flIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelFrontLeft];
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uint32_t frIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelFrontRight];
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uint32_t cIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelFrontCenter];
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uint32_t lfeIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelLFE];
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uint32_t blIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelBackLeft];
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uint32_t brIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelBackRight];
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uint32_t bcIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelBackCenter];
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uint32_t slIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelSideLeft];
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uint32_t srIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:AudioChannelSideRight];
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vDSP_vclr(outBuffer, 1, count * outchannels);
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if(flIndex != ~0)
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cblas_scopy((int)count, inBuffer + 0, 7, outBuffer + flIndex, outchannels);
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if(frIndex != ~0)
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cblas_scopy((int)count, inBuffer + 1, 7, outBuffer + frIndex, outchannels);
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if(cIndex != ~0)
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cblas_scopy((int)count, inBuffer + 2, 7, outBuffer + cIndex, outchannels);
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if(lfeIndex != ~0)
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cblas_scopy((int)count, inBuffer + 3, 7, outBuffer + lfeIndex, outchannels);
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if(slIndex != ~0)
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cblas_scopy((int)count, inBuffer + 4, 7, outBuffer + slIndex, outchannels);
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if(srIndex != ~0)
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cblas_scopy((int)count, inBuffer + 5, 7, outBuffer + srIndex, outchannels);
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if(bcIndex != ~0)
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cblas_scopy((int)count, inBuffer + 6, 7, outBuffer + bcIndex, outchannels);
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else {
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if(blIndex != ~0)
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cblas_scopy((int)count, inBuffer + 6, 7, outBuffer + blIndex, outchannels);
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if(brIndex != ~0)
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cblas_scopy((int)count, inBuffer + 6, 7, outBuffer + brIndex, outchannels);
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}
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} else {
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vDSP_vclr(outBuffer, 1, count * outchannels);
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for(int i = 0; i < inchannels; ++i) {
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uint32_t channelFlag = [AudioChunk extractChannelFlag:i fromConfig:inconfig];
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uint32_t outIndex = [AudioChunk channelIndexFromConfig:outconfig forFlag:channelFlag];
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if(outIndex != ~0)
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cblas_scopy((int)count, inBuffer + i, inchannels, outBuffer + outIndex, outchannels);
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}
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}
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}
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@implementation DownmixProcessor
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static void *kDownmixProcessorContext = &kDownmixProcessorContext;
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- (id)initWithInputFormat:(AudioStreamBasicDescription)inf inputConfig:(uint32_t)iConfig andOutputFormat:(AudioStreamBasicDescription)outf outputConfig:(uint32_t)oConfig {
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self = [super init];
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if(self) {
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if(inf.mFormatID != kAudioFormatLinearPCM ||
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(inf.mFormatFlags & kAudioFormatFlagsNativeFloatPacked) != kAudioFormatFlagsNativeFloatPacked ||
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inf.mBitsPerChannel != 32 ||
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inf.mBytesPerFrame != (4 * inf.mChannelsPerFrame) ||
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inf.mBytesPerPacket != inf.mFramesPerPacket * inf.mBytesPerFrame)
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return nil;
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if(outf.mFormatID != kAudioFormatLinearPCM ||
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(outf.mFormatFlags & kAudioFormatFlagsNativeFloatPacked) != kAudioFormatFlagsNativeFloatPacked ||
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outf.mBitsPerChannel != 32 ||
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outf.mBytesPerFrame != (4 * outf.mChannelsPerFrame) ||
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outf.mBytesPerPacket != outf.mFramesPerPacket * outf.mBytesPerFrame)
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return nil;
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inputFormat = inf;
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outputFormat = outf;
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inConfig = iConfig;
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outConfig = oConfig;
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}
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return self;
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}
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- (void)process:(const void *)inBuffer frameCount:(size_t)frames output:(void *)outBuffer {
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if(inputFormat.mChannelsPerFrame > 2 && outConfig == AudioConfigStereo) {
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downmix_to_stereo((const float *)inBuffer, inputFormat.mChannelsPerFrame, inConfig, (float *)outBuffer, frames);
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} else if(inputFormat.mChannelsPerFrame > 1 && outConfig == AudioConfigMono) {
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downmix_to_mono((const float *)inBuffer, inputFormat.mChannelsPerFrame, inConfig, (float *)outBuffer, frames);
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} else if(inputFormat.mChannelsPerFrame < outputFormat.mChannelsPerFrame) {
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upmix((const float *)inBuffer, inputFormat.mChannelsPerFrame, inConfig, (float *)outBuffer, outputFormat.mChannelsPerFrame, outConfig, frames);
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} else if(inConfig == outConfig) {
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memcpy(outBuffer, inBuffer, frames * outputFormat.mBytesPerPacket);
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}
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}
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@end
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