mirror of https://github.com/mpv-player/mpv
130 lines
3.3 KiB
C
130 lines
3.3 KiB
C
/* Audio out plugin it doesn't really do anything useful but serves
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an example of how audio plugins work. It delays the output signal
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by the nuber of samples set by delay=n where n is the number of
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bytes.
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*/
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#define PLUGIN
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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 "audio_out.h"
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#include "audio_plugin.h"
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#include "audio_plugin_internal.h"
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#include "afmt.h"
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static ao_info_t info =
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{
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"Delay audio plugin",
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"delay",
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"Anders",
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""
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};
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LIBAO_PLUGIN_EXTERN(delay)
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// local data
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typedef struct pl_delay_s
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{
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void* data; // local audio data block
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void* delay; // data block used for delaying audio signal
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int len; // local buffer length
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int rate; // local data rate
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int channels; // local number of channels
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int format; // local format
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} pl_delay_t;
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static pl_delay_t pl_delay={NULL,NULL,0,0,0,0};
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// to set/get/query special features/parameters
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static int control(int cmd,void *arg){
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switch(cmd){
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case AOCONTROL_PLUGIN_SET_LEN:
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if(pl_delay.data)
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free(pl_delay.data);
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pl_delay.len = ao_plugin_data.len;
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pl_delay.data=(void*)malloc(ao_plugin_data.len);
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if(!pl_delay.data)
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return CONTROL_ERROR;
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return CONTROL_OK;
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}
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return -1;
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}
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// open & setup audio device
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// return: 1=success 0=fail
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static int init(){
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float time_delay; // The time in [s] this plugin delays the output data
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/* If the output format of any of the below parameters differs from
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what is give it should be changed. See ao_plugin init() */
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pl_delay.rate=ao_plugin_data.rate;
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pl_delay.channels=ao_plugin_data.channels; //1=mono 2=stereo
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pl_delay.format=ao_plugin_data.format;
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// Tell ao_plugin how much this plugin adds to the overall time delay
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time_delay=-1*(float)ao_plugin_cfg.pl_delay_len/((float)pl_delay.channels*(float)pl_delay.rate);
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if(pl_delay.format != AFMT_U8 && pl_delay.format != AFMT_S8)
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time_delay/=2;
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ao_plugin_data.delay_fix+=time_delay;
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// Create buffer for the delayed data
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pl_delay.delay=(void*)malloc(ao_plugin_cfg.pl_delay_len);
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if(!pl_delay.delay)
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return 0;
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memset(pl_delay.delay, 0, ao_plugin_cfg.pl_delay_len);
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// Print some cool remark of what the plugin does
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printf("[pl_delay] Output sound delayed by %i bytes\n",ao_plugin_cfg.pl_delay_len);
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return 1;
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}
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// close plugin
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static void uninit(){
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if(pl_delay.delay)
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free(pl_delay.delay);
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if(pl_delay.data)
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free(pl_delay.data);
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ao_plugin_cfg.pl_delay_len=0;
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}
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// empty buffers
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static void reset(){
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int i = 0;
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for(i=0;i<pl_delay.len;i++)
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((char*)pl_delay.data)[i]=0;
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for(i=0;i<ao_plugin_cfg.pl_delay_len;i++)
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((char*)pl_delay.delay)[i]=0;
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}
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// processes 'ao_plugin_data.len' bytes of 'data'
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// called for every block of data
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static int play(){
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// Copy end of prev block to begining of buffer
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memcpy(pl_delay.data,pl_delay.delay,ao_plugin_cfg.pl_delay_len);
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// Copy current block except end
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memcpy(pl_delay.data+ao_plugin_cfg.pl_delay_len,
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ao_plugin_data.data,
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ao_plugin_data.len-ao_plugin_cfg.pl_delay_len);
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// Save away end of current block for next call
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memcpy(pl_delay.delay,
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ao_plugin_data.data+ao_plugin_data.len-ao_plugin_cfg.pl_delay_len,
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ao_plugin_cfg.pl_delay_len);
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// Set output data block
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ao_plugin_data.data=pl_delay.data;
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return 1;
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}
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