cog/Audio/Chain/Downmix.m

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