chris/Cog
2
1
Fork 0
Code Issues 65 Pull requests Projects Releases Packages Wiki Activity Actions
Cog/Audio/Chain/Downmix.m
Christopher Snowhill 62edb39761 Cog Audio: Major rewrite of audio buffering 
Rewrite attempt number two. Now using array lists of audio chunks, with
each chunk having its format and optionally losslessness stashed along
with it. This replaces the old virtual ring buffer method. As a result
of this, the HRIR toggle now works instantaneously.

Signed-off-by: Christopher Snowhill <kode54@gmail.com>
2022-02-06 03:08:34 -08:00

303 lines
10 KiB
Objective-C
Raw Blame History

//
// Downmix.m
// Cog
//
// Created by Christopher Snowhill on 2/05/22.
// Copyright 2022 __LoSnoCo__. All rights reserved.
//
#import "Downmix.h"
#import "Logging.h"
static const float STEREO_DOWNMIX[8-2][8][2]={
/*3.0*/
{
{0.5858F,0.0F},{0.0F,0.5858F},{0.4142F,0.4142F}
},
/*quadrophonic*/
{
{0.4226F,0.0F},{0.0F,0.4226F},{0.366F,0.2114F},{0.2114F,0.336F}
},
/*5.0*/
{
{0.651F,0.0F},{0.0F,0.651F},{0.46F,0.46F},{0.5636F,0.3254F},
{0.3254F,0.5636F}
},
/*5.1*/
{
{0.529F,0.0F},{0.0F,0.529F},{0.3741F,0.3741F},{0.3741F,0.3741F},{0.4582F,0.2645F},
{0.2645F,0.4582F}
},
/*6.1*/
{
{0.4553F,0.0F},{0.0F,0.4553F},{0.322F,0.322F},{0.322F,0.322F},{0.2788F,0.2788F},
{0.3943F,0.2277F},{0.2277F,0.3943F}
},
/*7.1*/
{
{0.3886F,0.0F},{0.0F,0.3886F},{0.2748F,0.2748F},{0.2748F,0.2748F},{0.3366F,0.1943F},
{0.1943F,0.3366F},{0.3366F,0.1943F},{0.1943F,0.3366F}
}
};
static void downmix_to_stereo(const float * inBuffer, int channels, float * outBuffer, size_t count)
{
if (channels >= 3 && channels <= 8)
for (size_t i = 0; i < count; ++i)
{
float left = 0, right = 0;
for (int j = 0; j < channels; ++j)
{
left += inBuffer[i * channels + j] * STEREO_DOWNMIX[channels - 3][j][0];
right += inBuffer[i * channels + j] * STEREO_DOWNMIX[channels - 3][j][1];
}
outBuffer[i * 2 + 0] = left;
outBuffer[i * 2 + 1] = right;
}
}
static void downmix_to_mono(const float * inBuffer, int channels, float * outBuffer, size_t count)
{
float tempBuffer[count * 2];
if (channels >= 3 && channels <= 8)
{
downmix_to_stereo(inBuffer, channels, tempBuffer, count);
inBuffer = tempBuffer;
channels = 2;
}
float invchannels = 1.0 / (float)channels;
for (size_t i = 0; i < count; ++i)
{
float sample = 0;
for (int j = 0; j < channels; ++j)
{
sample += inBuffer[i * channels + j];
}
outBuffer[i] = sample * invchannels;
}
}
static void upmix(const float * inBuffer, int inchannels, float * outBuffer, int outchannels, size_t count)
{
for (ssize_t i = 0; i < count; ++i)
{
if (inchannels == 1 && outchannels == 2)
{
// upmix mono to stereo
float sample = inBuffer[i];
outBuffer[i * 2 + 0] = sample;
outBuffer[i * 2 + 1] = sample;
}
else if (inchannels == 1 && outchannels == 4)
{
// upmix mono to quad
float sample = inBuffer[i];
outBuffer[i * 4 + 0] = sample;
outBuffer[i * 4 + 1] = sample;
outBuffer[i * 4 + 2] = 0;
outBuffer[i * 4 + 3] = 0;
}
else if (inchannels == 1 && (outchannels == 3 || outchannels >= 5))
{
// upmix mono to center channel
float sample = inBuffer[i];
outBuffer[i * outchannels + 2] = sample;
for (int j = 0; j < 2; ++j)
{
outBuffer[i * outchannels + j] = 0;
}
for (int j = 3; j < outchannels; ++j)
{
outBuffer[i * outchannels + j] = 0;
}
}
else if (inchannels == 4 && outchannels >= 5)
{
float fl = inBuffer[i * 4 + 0];
float fr = inBuffer[i * 4 + 1];
float bl = inBuffer[i * 4 + 2];
float br = inBuffer[i * 4 + 3];
const int skipclfe = (outchannels == 5) ? 1 : 2;
outBuffer[i * outchannels + 0] = fl;
outBuffer[i * outchannels + 1] = fr;
outBuffer[i * outchannels + skipclfe + 2] = bl;
outBuffer[i * outchannels + skipclfe + 3] = br;
for (int j = 0; j < skipclfe; ++j)
{
outBuffer[i * outchannels + 2 + j] = 0;
}
for (int j = 4 + skipclfe; j < outchannels; ++j)
{
outBuffer[i * outchannels + j] = 0;
}
}
else if (inchannels == 5 && outchannels >= 6)
{
float fl = inBuffer[i * 5 + 0];
float fr = inBuffer[i * 5 + 1];
float c = inBuffer[i * 5 + 2];
float bl = inBuffer[i * 5 + 3];
float br = inBuffer[i * 5 + 4];
outBuffer[i * outchannels + 0] = fl;
outBuffer[i * outchannels + 1] = fr;
outBuffer[i * outchannels + 2] = c;
outBuffer[i * outchannels + 3] = 0;
outBuffer[i * outchannels + 4] = bl;
outBuffer[i * outchannels + 5] = br;
for (int j = 6; j < outchannels; ++j)
{
outBuffer[i * outchannels + j] = 0;
}
}
else if (inchannels == 7 && outchannels == 8)
{
float fl = inBuffer[i * 7 + 0];
float fr = inBuffer[i * 7 + 1];
float c = inBuffer[i * 7 + 2];
float lfe = inBuffer[i * 7 + 3];
float sl = inBuffer[i * 7 + 4];
float sr = inBuffer[i * 7 + 5];
float bc = inBuffer[i * 7 + 6];
outBuffer[i * 8 + 0] = fl;
outBuffer[i * 8 + 1] = fr;
outBuffer[i * 8 + 2] = c;
outBuffer[i * 8 + 3] = lfe;
outBuffer[i * 8 + 4] = bc;
outBuffer[i * 8 + 5] = bc;
outBuffer[i * 8 + 6] = sl;
outBuffer[i * 8 + 7] = sr;
}
else
{
// upmix N channels to N channels plus silence the empty channels
float samples[inchannels];
for (int j = 0; j < inchannels; ++j)
{
samples[j] = inBuffer[i * inchannels + j];
}
for (int j = 0; j < inchannels; ++j)
{
outBuffer[i * outchannels + j] = samples[j];
}
for (int j = inchannels; j < outchannels; ++j)
{
outBuffer[i * outchannels + j] = 0;
}
}
}
}
@implementation DownmixProcessor
- (id) initWithInputFormat:(AudioStreamBasicDescription)inf andOutputFormat:(AudioStreamBasicDescription)outf {
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;
[self setupVirt];
[[NSUserDefaultsController sharedUserDefaultsController] addObserver:self forKeyPath:@"values.headphoneVirtualization" options:0 context:nil];
[[NSUserDefaultsController sharedUserDefaultsController] addObserver:self forKeyPath:@"values.hrirPath" options:0 context:nil];
}
return self;
}
- (void) dealloc {
[[NSUserDefaultsController sharedUserDefaultsController] removeObserver:self forKeyPath:@"values.headphoneVirtualization"];
[[NSUserDefaultsController sharedUserDefaultsController] removeObserver:self forKeyPath:@"values.hrirPath"];
}
- (void) setupVirt {
@synchronized(hFilter) {
hFilter = nil;
}
BOOL hVirt = [[[NSUserDefaultsController sharedUserDefaultsController] defaults] boolForKey:@"headphoneVirtualization"];
if (hVirt &&
outputFormat.mChannelsPerFrame == 2 &&
inputFormat.mChannelsPerFrame >= 1 &&
inputFormat.mChannelsPerFrame <= 8) {
NSString * userPreset = [[[NSUserDefaultsController sharedUserDefaultsController] defaults] stringForKey:@"hrirPath"];
NSURL * presetUrl = nil;
if (userPreset && ![userPreset isEqualToString:@""]) {
presetUrl = [NSURL fileURLWithPath:userPreset];
if (![HeadphoneFilter validateImpulseFile:presetUrl])
presetUrl = nil;
}
if (!presetUrl) {
presetUrl = [[NSBundle mainBundle] URLForResource:@"gsx" withExtension:@"wv"];
if (![HeadphoneFilter validateImpulseFile:presetUrl])
presetUrl = nil;
}
if (presetUrl) {
@synchronized(hFilter) {
hFilter = [[HeadphoneFilter alloc] initWithImpulseFile:presetUrl forSampleRate:outputFormat.mSampleRate withInputChannels:inputFormat.mChannelsPerFrame];
}
}
}
}
- (void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context
{
DLog(@"SOMETHING CHANGED!");
if ([keyPath isEqualToString:@"values.headphoneVirtualization"] ||
[keyPath isEqualToString:@"values.hrirPath"]) {
// Reset the converter, without rebuffering
[self setupVirt];
}
}
- (void) process:(const void *)inBuffer frameCount:(size_t)frames output:(void *)outBuffer {
@synchronized (hFilter) {
if ( hFilter ) {
[hFilter process:(const float *) inBuffer sampleCount:frames toBuffer:(float *) outBuffer];
return;
}
}
if ( inputFormat.mChannelsPerFrame > 2 && outputFormat.mChannelsPerFrame == 2 )
{
downmix_to_stereo( (const float*) inBuffer, inputFormat.mChannelsPerFrame, (float*) outBuffer, frames );
}
else if ( inputFormat.mChannelsPerFrame > 1 && outputFormat.mChannelsPerFrame == 1 )
{
downmix_to_mono( (const float*) inBuffer, inputFormat.mChannelsPerFrame, (float*) outBuffer, frames );
}
else if ( inputFormat.mChannelsPerFrame < outputFormat.mChannelsPerFrame )
{
upmix( (const float*) inBuffer, inputFormat.mChannelsPerFrame, (float*) outBuffer, outputFormat.mChannelsPerFrame, frames );
}
else if ( inputFormat.mChannelsPerFrame == outputFormat.mChannelsPerFrame )
{
memcpy(outBuffer, inBuffer, frames * outputFormat.mBytesPerPacket);
}
}
@end
Reference in a new issue View git blame Copy permalink