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/*
* null audio output driver
*
* This file is part of MPlayer.
*
* MPlayer is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* MPlayer is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with MPlayer; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include "config.h"
#include "libaf/af_format.h"
#include "audio_out.h"
#include "audio_out_internal.h"
static const ao_info_t info =
{
"Null audio output",
"null",
"Tobias Diedrich <ranma+mplayer@tdiedrich.de>",
""
};
LIBAO_EXTERN(null)
struct timeval last_tv;
int buffer;
static void drain(void){
struct timeval now_tv;
int temp, temp2;
gettimeofday(&now_tv, 0);
temp = now_tv.tv_sec - last_tv.tv_sec;
temp *= ao_data.bps;
temp2 = now_tv.tv_usec - last_tv.tv_usec;
temp2 /= 1000;
temp2 *= ao_data.bps;
temp2 /= 1000;
temp += temp2;
buffer-=temp;
if (buffer<0) buffer=0;
if(temp>0) last_tv = now_tv;//mplayer is fast
}
// to set/get/query special features/parameters
static int control(int cmd,void *arg){
return -1;
}
// open & setup audio device
// return: 1=success 0=fail
static int init(int rate,int channels,int format,int flags){
int samplesize = af_fmt2bits(format) / 8;
ao_data.outburst = 256 * channels * samplesize;
// A "buffer" for about 0.2 seconds of audio
ao_data.buffersize = (int)(rate * 0.2 / 256 + 1) * ao_data.outburst;
ao_data.channels=channels;
ao_data.samplerate=rate;
ao_data.format=format;
ao_data.bps=channels*rate*samplesize;
buffer=0;
gettimeofday(&last_tv, 0);
return 1;
}
// close audio device
static void uninit(int immed){
}
// stop playing and empty buffers (for seeking/pause)
static void reset(void){
buffer=0;
}
// stop playing, keep buffers (for pause)
static void audio_pause(void)
{
// for now, just call reset();
reset();
}
// resume playing, after audio_pause()
static void audio_resume(void)
{
}
// return: how many bytes can be played without blocking
static int get_space(void){
drain();
return ao_data.buffersize - buffer;
}
// plays 'len' bytes of 'data'
// it should round it down to outburst*n
// return: number of bytes played
static int play(void* data,int len,int flags){
int maxbursts = (ao_data.buffersize - buffer) / ao_data.outburst;
int playbursts = len / ao_data.outburst;
int bursts = playbursts > maxbursts ? maxbursts : playbursts;
buffer += bursts * ao_data.outburst;
return bursts * ao_data.outburst;
}
// return: delay in seconds between first and last sample in buffer
static float get_delay(void){
drain();
return (float) buffer / (float) ao_data.bps;
}
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