mirror of https://github.com/mpv-player/mpv
130 lines
3.2 KiB
C
130 lines
3.2 KiB
C
/*
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* null audio output driver
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*
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* This file is part of MPlayer.
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*
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* MPlayer is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* MPlayer is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with MPlayer; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "talloc.h"
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#include "config.h"
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#include "osdep/timer.h"
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#include "audio/format.h"
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#include "ao.h"
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struct priv {
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unsigned last_time;
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float buffered_bytes;
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};
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static void drain(struct ao *ao)
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{
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struct priv *priv = ao->priv;
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unsigned now = GetTimer();
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priv->buffered_bytes -= (now - priv->last_time) / 1e6 * ao->bps;
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if (priv->buffered_bytes < 0)
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priv->buffered_bytes = 0;
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priv->last_time = now;
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}
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static int init(struct ao *ao, char *params)
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{
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struct priv *priv = talloc_zero(ao, struct priv);
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ao->priv = priv;
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int samplesize = af_fmt2bits(ao->format) / 8;
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ao->outburst = 256 * ao->channels * samplesize;
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// A "buffer" for about 0.2 seconds of audio
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ao->buffersize = (int)(ao->samplerate * 0.2 / 256 + 1) * ao->outburst;
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ao->bps = ao->channels * ao->samplerate * samplesize;
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priv->last_time = GetTimer();
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return 0;
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}
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// close audio device
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static void uninit(struct ao *ao, bool cut_audio)
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{
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}
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// stop playing and empty buffers (for seeking/pause)
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static void reset(struct ao *ao)
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{
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struct priv *priv = ao->priv;
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priv->buffered_bytes = 0;
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}
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// stop playing, keep buffers (for pause)
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static void pause(struct ao *ao)
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{
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// for now, just call reset();
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reset(ao);
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}
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// resume playing, after audio_pause()
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static void resume(struct ao *ao)
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{
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}
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static int get_space(struct ao *ao)
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{
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struct priv *priv = ao->priv;
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drain(ao);
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return ao->buffersize - priv->buffered_bytes;
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}
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static int play(struct ao *ao, void *data, int len, int flags)
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{
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struct priv *priv = ao->priv;
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int maxbursts = (ao->buffersize - priv->buffered_bytes) / ao->outburst;
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int playbursts = len / ao->outburst;
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int bursts = playbursts > maxbursts ? maxbursts : playbursts;
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priv->buffered_bytes += bursts * ao->outburst;
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return bursts * ao->outburst;
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}
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static float get_delay(struct ao *ao)
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{
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struct priv *priv = ao->priv;
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drain(ao);
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return priv->buffered_bytes / ao->bps;
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}
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const struct ao_driver audio_out_null = {
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.is_new = true,
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.info = &(const struct ao_info) {
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"Null audio output",
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"null",
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"Tobias Diedrich <ranma+mplayer@tdiedrich.de>",
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"",
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},
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.init = init,
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.uninit = uninit,
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.reset = reset,
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.get_space = get_space,
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.play = play,
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.get_delay = get_delay,
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.pause = pause,
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.resume = resume,
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};
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