cog/Audio/Output/FSurroundFilter.mm

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//
// FSurroundFilter.m
// CogAudio Framework
//
// Created by Christopher Snowhill on 7/9/22.
//
#import "FSurroundFilter.h"
#import "freesurround_decoder.h"
#import "AudioChunk.h"
#import <Accelerate/Accelerate.h>
#import <map>
#import <vector>
struct freesurround_params {
// the user-configurable parameters
float center_image, shift, depth, circular_wrap, focus, front_sep, rear_sep, bass_lo, bass_hi;
bool use_lfe;
channel_setup channels_fs; // FreeSurround channel setup
std::vector<unsigned> chanmap; // FreeSurround -> WFX channel index translation (derived data for faster lookup)
// construct with defaults
freesurround_params()
: center_image(0.7), shift(0), depth(1), circular_wrap(90), focus(0), front_sep(1), rear_sep(1),
bass_lo(40), bass_hi(90), use_lfe(false) {
set_channels_fs(cs_5point1);
}
// compute the WFX version of the channel setup code
unsigned channel_count() {
return (unsigned)chanmap.size();
}
unsigned channels_wfx() {
unsigned res = 0;
for(unsigned i = 0; i < chanmap.size(); res |= chanmap[i++]) {};
return res;
}
// assign a channel setup & recompute derived data
void set_channels_fs(channel_setup setup) {
channels_fs = setup;
chanmap.clear();
// Note: Because WFX does not define a few of the more exotic channels (side front left&right, side rear left&right, back center left&right),
// the side front/back channel pairs (both left and right sides, resp.) are mapped here onto foobar's top front/back channel pairs and the
// back (off-)center left/right channels are mapped onto foobar's top front center and top back center, respectively.
// Therefore, these speakers should be connected to those outputs instead.
std::map<channel_id, uint32_t> fs2wfx;
fs2wfx[ci_front_left] = AudioChannelFrontLeft;
fs2wfx[ci_front_center_left] = AudioChannelFrontCenterLeft;
fs2wfx[ci_front_center] = AudioChannelFrontCenter;
fs2wfx[ci_front_center_right] = AudioChannelFrontCenterRight;
fs2wfx[ci_front_right] = AudioChannelFrontRight;
fs2wfx[ci_side_front_left] = AudioChannelFrontLeft;
fs2wfx[ci_side_front_right] = AudioChannelTopFrontRight;
fs2wfx[ci_side_center_left] = AudioChannelSideLeft;
fs2wfx[ci_side_center_right] = AudioChannelSideRight;
fs2wfx[ci_side_back_left] = AudioChannelTopBackLeft;
fs2wfx[ci_side_back_right] = AudioChannelTopBackRight;
fs2wfx[ci_back_left] = AudioChannelBackLeft;
fs2wfx[ci_back_center_left] = AudioChannelTopFrontCenter;
fs2wfx[ci_back_center] = AudioChannelBackCenter;
fs2wfx[ci_back_center_right] = AudioChannelTopBackCenter;
fs2wfx[ci_back_right] = AudioChannelBackRight;
fs2wfx[ci_lfe] = AudioChannelLFE;
for(unsigned i = 0; i < freesurround_decoder::num_channels(channels_fs); i++)
chanmap.push_back(fs2wfx[freesurround_decoder::channel_at(channels_fs, i)]);
}
};
@implementation FSurroundFilter
- (id)initWithSampleRate:(double)srate {
self = [super init];
if(!self) return nil;
self->srate = srate;
freesurround_params *_params = new freesurround_params;
params = (void *)_params;
freesurround_decoder *_decoder = new freesurround_decoder(cs_5point1, 4096);
decoder = (void *)_decoder;
_decoder->circular_wrap(_params->circular_wrap);
_decoder->shift(_params->shift);
_decoder->depth(_params->depth);
_decoder->focus(_params->focus);
_decoder->center_image(_params->center_image);
_decoder->front_separation(_params->front_sep);
_decoder->rear_separation(_params->rear_sep);
_decoder->bass_redirection(_params->use_lfe);
_decoder->low_cutoff(_params->bass_lo / (srate / 2.0));
_decoder->high_cutoff(_params->bass_hi / (srate / 2.0));
channelCount = _params->channel_count();
channelConfig = _params->channels_wfx();
return self;
}
- (void)dealloc {
if(decoder) {
freesurround_decoder *_decoder = (freesurround_decoder *)decoder;
delete _decoder;
}
if(params) {
freesurround_params *_params = (freesurround_params *)params;
delete _params;
}
}
- (uint32_t)channelCount {
return channelCount;
}
- (uint32_t)channelConfig {
return channelConfig;
}
- (double)srate {
return srate;
}
- (void)process:(const float *)samplesIn output:(float *)samplesOut count:(uint32_t)count {
freesurround_params *_params = (freesurround_params *)params;
freesurround_decoder *_decoder = (freesurround_decoder *)decoder;
float tempInput[4096 * 2];
uint32_t zeroCount = 0;
if(count > 4096) {
zeroCount = count - 4096;
count = 4096;
}
if(count < 4096) {
cblas_scopy(count * 2, samplesIn, 1, &tempInput[0], 1);
vDSP_vclr(&tempInput[count * 2], 1, (4096 - count) * 2);
samplesIn = &tempInput[0];
}
float *src = _decoder->decode(samplesIn);
for(unsigned c = 0, num = channelCount; c < num; c++) {
unsigned idx = [AudioChunk channelIndexFromConfig:channelConfig forFlag:_params->chanmap[c]];
cblas_scopy(count, src + c, num, samplesOut + idx, num);
if(zeroCount) {
vDSP_vclr(samplesOut + idx + count, num, zeroCount);
}
}
}
@end