diff options
Diffstat (limited to 'libaf/af_extrastereo.c')
-rw-r--r-- | libaf/af_extrastereo.c | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/libaf/af_extrastereo.c b/libaf/af_extrastereo.c new file mode 100644 index 0000000000..a8857b4b33 --- /dev/null +++ b/libaf/af_extrastereo.c @@ -0,0 +1,120 @@ +/*============================================================================= +// +// This software has been released under the terms of the GNU Public +// license. See http://www.gnu.org/copyleft/gpl.html for details. +// +// Copyright 2004 Alex Beregszaszi & Pierre Lombard +// +//============================================================================= +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include <unistd.h> +#include <inttypes.h> +#include <math.h> +#include <limits.h> + +#include "af.h" + +// Data for specific instances of this filter +typedef struct af_extrastereo_s +{ + float mul; +}af_extrastereo_t; + +// Initialization and runtime control +static int control(struct af_instance_s* af, int cmd, void* arg) +{ + af_extrastereo_t* s = (af_extrastereo_t*)af->setup; + + switch(cmd){ + case AF_CONTROL_REINIT: + // Sanity check + if(!arg) return AF_ERROR; + + if(((af_data_t*)arg)->format != (AF_FORMAT_SI | AF_FORMAT_NE) || + (((af_data_t*)arg)->nch != 2)) + return AF_ERROR; + + af->data->rate = ((af_data_t*)arg)->rate; + af->data->nch = 2; + af->data->format = AF_FORMAT_SI | AF_FORMAT_NE; + af->data->bps = 2; + + return af_test_output(af,(af_data_t*)arg); + case AF_CONTROL_COMMAND_LINE:{ + float f; + sscanf((char*)arg,"%f", &f); + s->mul = f; + return AF_OK; + } + case AF_CONTROL_ES_MUL | AF_CONTROL_SET: + s->mul = *(float*)arg; + return AF_OK; + case AF_CONTROL_ES_MUL | AF_CONTROL_GET: + *(float*)arg = s->mul; + return AF_OK; + } + return AF_UNKNOWN; +} + +// Deallocate memory +static void uninit(struct af_instance_s* af) +{ + if(af->data) + free(af->data); + if(af->setup) + free(af->setup); +} + +// Filter data through filter +static af_data_t* play(struct af_instance_s* af, af_data_t* data) +{ + af_extrastereo_t *s = af->setup; + register int i = 0; + int16_t *a = (int16_t*)data->audio; // Audio data + int len = data->len/2; // Number of samples + int avg, l, r; + + for (i = 0; i < len; i+=2) + { + avg = (a[i] + a[i + 1]) / 2; + + l = avg + (int)(s->mul * (a[i] - avg)); + r = avg + (int)(s->mul * (a[i + 1] - avg)); + + a[i] = clamp(l, SHRT_MIN, SHRT_MAX); + a[i + 1] = clamp(r, SHRT_MIN, SHRT_MAX); + } + + return data; +} + +// Allocate memory and set function pointers +static int open(af_instance_t* af){ + af->control=control; + af->uninit=uninit; + af->play=play; + af->mul.n=1; + af->mul.d=1; + af->data=calloc(1,sizeof(af_data_t)); + af->setup=calloc(1,sizeof(af_extrastereo_t)); + if(af->data == NULL || af->setup == NULL) + return AF_ERROR; + + ((af_extrastereo_t*)af->setup)->mul = 2.5; + return AF_OK; +} + +// Description of this filter +af_info_t af_info_extrastereo = { + "Extra stereo", + "extrastereo", + "Alex Beregszaszi & Pierre Lombard", + "", + AF_FLAGS_NOT_REENTRANT, + open +}; |