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mpv/audio/out/ao_null.c
wm4 e56d8a200d Replace all calls to GetTimer()/GetTimerMS()
GetTimer() is generally replaced with mp_time_us(). Both calls return
microseconds, but the latter uses int64_t, us defined to never wrap,
and never returns 0 or negative values.

GetTimerMS() has no direct replacement. Instead the other functions are
used.

For some code, switch to mp_time_sec(), which returns the time as double
float value in seconds. The returned time is offset to program start
time, so there is enough precision left to deliver microsecond
resolution for at least 100 years. Unless it's casted to a float
(or the CPU reduces precision), which is why we still use mp_time_us()
out of paranoia in places where precision is clearly needed.

Always switch to the correct time. The whole point of the new timer
calls is that they don't wrap, and storing microseconds in unsigned int
variables would negate this.

In some cases, remove wrap-around handling for time values.
2013-05-26 16:44:20 +02:00

135 lines
3.3 KiB
C

/*
* 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 "talloc.h"
#include "config.h"
#include "osdep/timer.h"
#include "audio/format.h"
#include "ao.h"
struct priv {
double last_time;
float buffered_bytes;
};
static void drain(struct ao *ao)
{
struct priv *priv = ao->priv;
double now = mp_time_sec();
priv->buffered_bytes -= (now - priv->last_time) * ao->bps;
if (priv->buffered_bytes < 0)
priv->buffered_bytes = 0;
priv->last_time = now;
}
static int init(struct ao *ao, char *params)
{
struct priv *priv = talloc_zero(ao, struct priv);
ao->priv = priv;
struct mp_chmap_sel sel = {0};
mp_chmap_sel_add_any(&sel);
if (!ao_chmap_sel_adjust(ao, &sel, &ao->channels))
return -1;
int samplesize = af_fmt2bits(ao->format) / 8;
ao->outburst = 256 * ao->channels.num * samplesize;
// A "buffer" for about 0.2 seconds of audio
ao->buffersize = (int)(ao->samplerate * 0.2 / 256 + 1) * ao->outburst;
ao->bps = ao->channels.num * ao->samplerate * samplesize;
priv->last_time = mp_time_sec();
return 0;
}
// close audio device
static void uninit(struct ao *ao, bool cut_audio)
{
}
// stop playing and empty buffers (for seeking/pause)
static void reset(struct ao *ao)
{
struct priv *priv = ao->priv;
priv->buffered_bytes = 0;
}
// stop playing, keep buffers (for pause)
static void pause(struct ao *ao)
{
// for now, just call reset();
reset(ao);
}
// resume playing, after audio_pause()
static void resume(struct ao *ao)
{
}
static int get_space(struct ao *ao)
{
struct priv *priv = ao->priv;
drain(ao);
return ao->buffersize - priv->buffered_bytes;
}
static int play(struct ao *ao, void *data, int len, int flags)
{
struct priv *priv = ao->priv;
int maxbursts = (ao->buffersize - priv->buffered_bytes) / ao->outburst;
int playbursts = len / ao->outburst;
int bursts = playbursts > maxbursts ? maxbursts : playbursts;
priv->buffered_bytes += bursts * ao->outburst;
return bursts * ao->outburst;
}
static float get_delay(struct ao *ao)
{
struct priv *priv = ao->priv;
drain(ao);
return priv->buffered_bytes / ao->bps;
}
const struct ao_driver audio_out_null = {
.info = &(const struct ao_info) {
"Null audio output",
"null",
"Tobias Diedrich <ranma+mplayer@tdiedrich.de>",
"",
},
.init = init,
.uninit = uninit,
.reset = reset,
.get_space = get_space,
.play = play,
.get_delay = get_delay,
.pause = pause,
.resume = resume,
};