mirror of
https://github.com/mpv-player/mpv
synced 2024-12-13 10:26:00 +00:00
d04df91cbe
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@12642 b3059339-0415-0410-9bf9-f77b7e298cf2
228 lines
6.8 KiB
C
228 lines
6.8 KiB
C
/*=============================================================================
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//
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// This software has been released under the terms of the GNU Public
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// license. See http://www.gnu.org/copyleft/gpl.html for details.
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//
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// Copyright 2002 Anders Johansson ajh@atri.curtin.edu.au
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//
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//=============================================================================
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*/
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/* This audio filter changes the volume of the sound, and can be used
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when the mixer doesn't support the PCM channel. It can handle
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between 1 and 6 channels. The volume can be adjusted between -60dB
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to +20dB and is set on a per channels basis. The is accessed through
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AF_CONTROL_VOLUME_LEVEL.
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The filter has support for soft-clipping, it is enabled by
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AF_CONTROL_VOLUME_SOFTCLIPP. It has also a probing feature which
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can be used to measure the power in the audio stream, both an
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instantaneous value and the maximum value can be probed. The
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probing is enable by AF_CONTROL_VOLUME_PROBE_ON_OFF and is done on a
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per channel basis. The result from the probing is obtained using
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AF_CONTROL_VOLUME_PROBE_GET and AF_CONTROL_VOLUME_PROBE_GET_MAX. The
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probed values are calculated in dB.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <inttypes.h>
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#include <math.h>
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#include <limits.h>
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#include "af.h"
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// Data for specific instances of this filter
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typedef struct af_volume_s
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{
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int enable[AF_NCH]; // Enable/disable / channel
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float pow[AF_NCH]; // Estimated power level [dB]
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float max[AF_NCH]; // Max Power level [dB]
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float level[AF_NCH]; // Gain level for each channel
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float time; // Forgetting factor for power estimate
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int soft; // Enable/disable soft clipping
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int fast; // Use fix-point volume control
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}af_volume_t;
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// Initialization and runtime control
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static int control(struct af_instance_s* af, int cmd, void* arg)
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{
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af_volume_t* s = (af_volume_t*)af->setup;
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switch(cmd){
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case AF_CONTROL_REINIT:
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// Sanity check
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if(!arg) return AF_ERROR;
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af->data->rate = ((af_data_t*)arg)->rate;
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af->data->nch = ((af_data_t*)arg)->nch;
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if(s->fast && (((af_data_t*)arg)->format != (AF_FORMAT_F | AF_FORMAT_NE))){
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af->data->format = AF_FORMAT_SI | AF_FORMAT_NE;
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af->data->bps = 2;
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}
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else{
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// Cutoff set to 10Hz for forgetting factor
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float x = 2.0*M_PI*15.0/(float)af->data->rate;
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float t = 2.0-cos(x);
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s->time = 1.0 - (t - sqrt(t*t - 1));
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af_msg(AF_MSG_DEBUG0,"[volume] Forgetting factor = %0.5f\n",s->time);
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af->data->format = AF_FORMAT_F | AF_FORMAT_NE;
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af->data->bps = 4;
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}
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return af_test_output(af,(af_data_t*)arg);
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case AF_CONTROL_COMMAND_LINE:{
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float v=-10.0;
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float vol[AF_NCH];
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int i;
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sscanf((char*)arg,"%f:%i", &v, &s->soft);
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for(i=0;i<AF_NCH;i++) vol[i]=v;
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return control(af,AF_CONTROL_VOLUME_LEVEL | AF_CONTROL_SET, vol);
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}
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case AF_CONTROL_POST_CREATE:
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s->fast = ((((af_cfg_t*)arg)->force & AF_INIT_FORMAT_MASK) ==
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AF_INIT_FLOAT) ? 0 : 1;
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return AF_OK;
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case AF_CONTROL_VOLUME_ON_OFF | AF_CONTROL_SET:
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memcpy(s->enable,(int*)arg,AF_NCH*sizeof(int));
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return AF_OK;
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case AF_CONTROL_VOLUME_ON_OFF | AF_CONTROL_GET:
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memcpy((int*)arg,s->enable,AF_NCH*sizeof(int));
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return AF_OK;
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case AF_CONTROL_VOLUME_SOFTCLIP | AF_CONTROL_SET:
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s->soft = *(int*)arg;
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return AF_OK;
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case AF_CONTROL_VOLUME_SOFTCLIP | AF_CONTROL_GET:
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*(int*)arg = s->soft;
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return AF_OK;
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case AF_CONTROL_VOLUME_LEVEL | AF_CONTROL_SET:
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return af_from_dB(AF_NCH,(float*)arg,s->level,20.0,-200.0,60.0);
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case AF_CONTROL_VOLUME_LEVEL | AF_CONTROL_GET:
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return af_to_dB(AF_NCH,s->level,(float*)arg,20.0);
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case AF_CONTROL_VOLUME_PROBE | AF_CONTROL_GET:
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return af_to_dB(AF_NCH,s->pow,(float*)arg,10.0);
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case AF_CONTROL_VOLUME_PROBE_MAX | AF_CONTROL_GET:
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return af_to_dB(AF_NCH,s->max,(float*)arg,10.0);
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case AF_CONTROL_PRE_DESTROY:{
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float m = 0.0;
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int i;
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if(!s->fast){
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for(i=0;i<AF_NCH;i++)
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m=max(m,s->max[i]);
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af_to_dB(1, &m, &m, 10.0);
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af_msg(AF_MSG_INFO,"[volume] The maximum volume was %0.2fdB \n", m);
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}
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return AF_OK;
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}
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}
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return AF_UNKNOWN;
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}
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// Deallocate memory
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static void uninit(struct af_instance_s* af)
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{
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if(af->data)
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free(af->data);
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if(af->setup)
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free(af->setup);
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}
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// Filter data through filter
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static af_data_t* play(struct af_instance_s* af, af_data_t* data)
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{
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af_data_t* c = data; // Current working data
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af_volume_t* s = (af_volume_t*)af->setup; // Setup for this instance
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int ch = 0; // Channel counter
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register int nch = c->nch; // Number of channels
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register int i = 0;
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// Basic operation volume control only (used on slow machines)
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if(af->data->format == (AF_FORMAT_SI | AF_FORMAT_NE)){
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int16_t* a = (int16_t*)c->audio; // Audio data
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int len = c->len/2; // Number of samples
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for(ch = 0; ch < nch ; ch++){
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if(s->enable[ch]){
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register int vol = (int)(255.0 * s->level[ch]);
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for(i=ch;i<len;i+=nch){
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register int x = (a[i] * vol) >> 8;
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a[i]=clamp(x,SHRT_MIN,SHRT_MAX);
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}
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}
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}
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}
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// Machine is fast and data is floating point
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else if(af->data->format == (AF_FORMAT_F | AF_FORMAT_NE)){
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float* a = (float*)c->audio; // Audio data
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int len = c->len/4; // Number of samples
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for(ch = 0; ch < nch ; ch++){
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// Volume control (fader)
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if(s->enable[ch]){
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float t = 1.0 - s->time;
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for(i=ch;i<len;i+=nch){
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register float x = a[i];
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register float pow = x*x;
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// Check maximum power value
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if(pow > s->max[ch])
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s->max[ch] = pow;
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// Set volume
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x *= s->level[ch];
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// Peak meter
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pow = x*x;
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if(pow > s->pow[ch])
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s->pow[ch] = pow;
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else
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s->pow[ch] = t*s->pow[ch] + pow*s->time; // LP filter
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/* Soft clipping, the sound of a dream, thanks to Jon Wattes
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post to Musicdsp.org */
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if(s->soft){
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if (x >= M_PI/2)
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x = 1.0;
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else if(x <= -M_PI/2)
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x = -1.0;
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else
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x = sin(x);
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}
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// Hard clipping
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else
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x=clamp(x,-1.0,1.0);
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a[i] = x;
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}
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}
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}
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}
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return c;
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}
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// Allocate memory and set function pointers
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static int open(af_instance_t* af){
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int i = 0;
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af->control=control;
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af->uninit=uninit;
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af->play=play;
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af->mul.n=1;
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af->mul.d=1;
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af->data=calloc(1,sizeof(af_data_t));
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af->setup=calloc(1,sizeof(af_volume_t));
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if(af->data == NULL || af->setup == NULL)
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return AF_ERROR;
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// Enable volume control and set initial volume to 0dB.
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for(i=0;i<AF_NCH;i++){
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((af_volume_t*)af->setup)->enable[i] = 1;
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((af_volume_t*)af->setup)->level[i] = 1.0;
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}
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return AF_OK;
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}
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// Description of this filter
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af_info_t af_info_volume = {
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"Volume control audio filter",
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"volume",
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"Anders",
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"",
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AF_FLAGS_NOT_REENTRANT,
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open
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};
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