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🎥 Command line media player
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C
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232/* * null audio output driver * * This file is part of mpv. * * mpv is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * mpv 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 Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with mpv. If not, see <http://www.gnu.org/licenses/>. */
/* * Note: this does much more than just ignoring audio output. It simulates * (to some degree) an ideal AO. */
#include <stdio.h>#include <stdlib.h>#include <math.h>
#include "mpv_talloc.h"
#include "osdep/timer.h"#include "options/m_option.h"#include "common/common.h"#include "common/msg.h"#include "audio/format.h"#include "ao.h"#include "internal.h"
struct priv { bool paused; double last_time; float buffered; // samples int buffersize; // samples bool playing;
bool untimed; float bufferlen; // seconds float speed; // multiplier float latency_sec; // seconds float latency; // samples bool broken_eof; bool broken_delay;
// Minimal unit of audio samples that can be written at once. If play() is // called with sizes not aligned to this, a rounded size will be returned. // (This is not needed by the AO API, but many AOs behave this way.) int outburst; // samples
struct m_channels channel_layouts; int format;};
static void drain(struct ao *ao){ struct priv *priv = ao->priv;
if (ao->untimed) { priv->buffered = 0; return; }
if (priv->paused) return;
double now = mp_time_sec(); if (priv->buffered > 0) { priv->buffered -= (now - priv->last_time) * ao->samplerate * priv->speed; if (priv->buffered < 0) priv->buffered = 0; } priv->last_time = now;}
static int init(struct ao *ao){ struct priv *priv = ao->priv;
if (priv->format) ao->format = priv->format;
ao->untimed = priv->untimed;
struct mp_chmap_sel sel = {.tmp = ao}; if (priv->channel_layouts.num_chmaps) { for (int n = 0; n < priv->channel_layouts.num_chmaps; n++) mp_chmap_sel_add_map(&sel, &priv->channel_layouts.chmaps[n]); } else { mp_chmap_sel_add_any(&sel); } if (!ao_chmap_sel_adjust(ao, &sel, &ao->channels)) mp_chmap_from_channels(&ao->channels, 2);
priv->latency = priv->latency_sec * ao->samplerate;
// A "buffer" for this many seconds of audio int bursts = (int)(ao->samplerate * priv->bufferlen + 1) / priv->outburst; ao->device_buffer = priv->outburst * bursts + priv->latency;
priv->last_time = mp_time_sec();
return 0;}
// close audio devicestatic void uninit(struct ao *ao){}
// stop playing and empty buffers (for seeking)static void reset(struct ao *ao){ struct priv *priv = ao->priv; priv->paused = false; priv->buffered = 0; priv->playing = false;}
static void start(struct ao *ao){ struct priv *priv = ao->priv;
if (priv->paused) MP_ERR(ao, "illegal state: start() while paused\n");
drain(ao); priv->paused = false; priv->last_time = mp_time_sec(); priv->playing = true;}
static bool set_pause(struct ao *ao, bool paused){ struct priv *priv = ao->priv;
if (!priv->playing) MP_ERR(ao, "illegal state: set_pause() while not playing\n");
if (priv->paused != paused) {
drain(ao); priv->paused = paused; if (!priv->paused) priv->last_time = mp_time_sec(); }
return true;}
static bool audio_write(struct ao *ao, void **data, int samples){ struct priv *priv = ao->priv;
if (priv->buffered <= 0) priv->buffered = priv->latency; // emulate fixed latency
priv->buffered += samples; return true;}
static void get_state(struct ao *ao, struct mp_pcm_state *state){ struct priv *priv = ao->priv;
drain(ao);
state->free_samples = ao->device_buffer - priv->latency - priv->buffered; state->free_samples = state->free_samples / priv->outburst * priv->outburst; state->queued_samples = priv->buffered;
// Note how get_state returns the delay in audio device time (instead of // adjusting for speed), since most AOs seem to also do that. state->delay = priv->buffered;
// Drivers with broken EOF handling usually always report the same device- // level delay that is additional to the buffer time. if (priv->broken_eof && priv->buffered < priv->latency) state->delay = priv->latency;
state->delay /= ao->samplerate;
if (priv->broken_delay) { // Report only multiples of outburst double q = priv->outburst / (double)ao->samplerate; if (state->delay > 0) state->delay = (int)(state->delay / q) * q; }
state->playing = priv->playing && priv->buffered > 0;}
#define OPT_BASE_STRUCT struct priv
const struct ao_driver audio_out_null = { .description = "Null audio output", .name = "null", .init = init, .uninit = uninit, .reset = reset, .get_state = get_state, .set_pause = set_pause, .write = audio_write, .start = start, .priv_size = sizeof(struct priv), .priv_defaults = &(const struct priv) { .bufferlen = 0.2, .outburst = 256, .speed = 1, }, .options = (const struct m_option[]) { {"untimed", OPT_BOOL(untimed)}, {"buffer", OPT_FLOAT(bufferlen), M_RANGE(0, 100)}, {"outburst", OPT_INT(outburst), M_RANGE(1, 100000)}, {"speed", OPT_FLOAT(speed), M_RANGE(0, 10000)}, {"latency", OPT_FLOAT(latency_sec), M_RANGE(0, 100)}, {"broken-eof", OPT_BOOL(broken_eof)}, {"broken-delay", OPT_BOOL(broken_delay)}, {"channel-layouts", OPT_CHANNELS(channel_layouts)}, {"format", OPT_AUDIOFORMAT(format)}, {0} }, .options_prefix = "ao-null",};