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video.c
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/*
* 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/>.
*/
#include <stddef.h>
#include <stdbool.h>
#include <inttypes.h>
#include <math.h>
#include <assert.h>
#include "mpv_talloc.h"
#include "common/msg.h"
#include "options/options.h"
#include "options/m_config.h"
#include "options/m_option.h"
#include "common/common.h"
#include "common/encode.h"
#include "options/m_property.h"
#include "osdep/timer.h"
#include "audio/out/ao.h"
#include "audio/format.h"
#include "demux/demux.h"
#include "stream/stream.h"
#include "sub/osd.h"
#include "video/hwdec.h"
#include "filters/f_decoder_wrapper.h"
#include "video/out/vo.h"
#include "core.h"
#include "command.h"
#include "screenshot.h"
enum {
// update_video() - code also uses: <0 error, 0 eof, >0 progress
VD_ERROR = -1,
VD_EOF = 0, // end of file - no new output
VD_PROGRESS = 1, // progress, but no output; repeat call with no waiting
VD_NEW_FRAME = 2, // the call produced a new frame
VD_WAIT = 3, // no EOF, but no output; wait until wakeup
};
static const char av_desync_help_text[] =
"\n"
"Audio/Video desynchronisation detected! Possible reasons include too slow\n"
"hardware, temporary CPU spikes, broken drivers, and broken files. Audio\n"
"position will not match to the video (see A-V status field).\n"
"Consider trying `--profile=fast` and/or `--hwdec=auto-safe` as they may help.\n"
"\n";
static bool recreate_video_filters(struct MPContext *mpctx)
{
struct MPOpts *opts = mpctx->opts;
struct vo_chain *vo_c = mpctx->vo_chain;
assert(vo_c);
return mp_output_chain_update_filters(vo_c->filter, opts->vf_settings);
}
int reinit_video_filters(struct MPContext *mpctx)
{
struct vo_chain *vo_c = mpctx->vo_chain;
if (!vo_c)
return 0;
if (!recreate_video_filters(mpctx))
return -1;
mp_force_video_refresh(mpctx);
mp_notify(mpctx, MPV_EVENT_VIDEO_RECONFIG, NULL);
return 0;
}
static void vo_chain_reset_state(struct vo_chain *vo_c)
{
vo_seek_reset(vo_c->vo);
vo_c->underrun = false;
vo_c->underrun_signaled = false;
}
void reset_video_state(struct MPContext *mpctx)
{
if (mpctx->vo_chain) {
vo_chain_reset_state(mpctx->vo_chain);
struct track *t = mpctx->vo_chain->track;
if (t && t->dec)
mp_decoder_wrapper_set_play_dir(t->dec, mpctx->play_dir);
}
for (int n = 0; n < mpctx->num_next_frames; n++)
mp_image_unrefp(&mpctx->next_frames[n]);
mpctx->num_next_frames = 0;
mp_image_unrefp(&mpctx->saved_frame);
mpctx->delay = 0;
mpctx->time_frame = 0;
mpctx->video_pts = MP_NOPTS_VALUE;
mpctx->last_frame_duration = 0;
mpctx->num_past_frames = 0;
mpctx->total_avsync_change = 0;
mpctx->last_av_difference = 0;
mpctx->mistimed_frames_total = 0;
mpctx->drop_message_shown = 0;
mpctx->display_sync_drift_dir = 0;
mpctx->display_sync_error = 0;
mpctx->video_status = mpctx->vo_chain ? STATUS_SYNCING : STATUS_EOF;
}
void uninit_video_out(struct MPContext *mpctx)
{
uninit_video_chain(mpctx);
if (mpctx->video_out) {
vo_destroy(mpctx->video_out);
mpctx->video_out = NULL;
mp_notify(mpctx, MPV_EVENT_VIDEO_RECONFIG, NULL);
}
}
static void vo_chain_uninit(struct vo_chain *vo_c)
{
struct track *track = vo_c->track;
if (track) {
assert(track->vo_c == vo_c);
track->vo_c = NULL;
if (vo_c->dec_src)
assert(track->dec->f->pins[0] == vo_c->dec_src);
talloc_free(track->dec->f);
track->dec = NULL;
}
if (vo_c->filter_src)
mp_pin_disconnect(vo_c->filter_src);
talloc_free(vo_c->filter->f);
talloc_free(vo_c);
// this does not free the VO
}
void uninit_video_chain(struct MPContext *mpctx)
{
if (mpctx->vo_chain) {
reset_video_state(mpctx);
vo_chain_uninit(mpctx->vo_chain);
mpctx->vo_chain = NULL;
mpctx->video_status = STATUS_EOF;
mp_notify(mpctx, MPV_EVENT_VIDEO_RECONFIG, NULL);
}
}
int init_video_decoder(struct MPContext *mpctx, struct track *track)
{
assert(!track->dec);
if (!track->stream)
goto err_out;
struct mp_filter *parent = mpctx->filter_root;
// If possible, set this as parent so the decoder gets the hwdec and DR
// interfaces.
// Note: We rely on being able to get rid of all references to the VO by
// destroying the VO chain. Thus, decoders not linked to vo_chain
// must not use the hwdec context.
if (track->vo_c)
parent = track->vo_c->filter->f;
track->dec = mp_decoder_wrapper_create(parent, track->stream);
if (!track->dec)
goto err_out;
if (!mp_decoder_wrapper_reinit(track->dec))
goto err_out;
return 1;
err_out:
if (track->sink)
mp_pin_disconnect(track->sink);
track->sink = NULL;
error_on_track(mpctx, track);
return 0;
}
void reinit_video_chain(struct MPContext *mpctx)
{
struct track *track = mpctx->current_track[0][STREAM_VIDEO];
if (!track || !track->stream) {
error_on_track(mpctx, track);
return;
}
reinit_video_chain_src(mpctx, track);
}
static void filter_update_subtitles(void *ctx, double pts)
{
struct MPContext *mpctx = ctx;
if (osd_get_render_subs_in_filter(mpctx->osd))
update_subtitles(mpctx, pts);
}
// (track=NULL creates a blank chain, used for lavfi-complex)
void reinit_video_chain_src(struct MPContext *mpctx, struct track *track)
{
assert(!mpctx->vo_chain);
if (!mpctx->video_out) {
struct vo_extra ex = {
.input_ctx = mpctx->input,
.osd = mpctx->osd,
.encode_lavc_ctx = mpctx->encode_lavc_ctx,
.wakeup_cb = mp_wakeup_core_cb,
.wakeup_ctx = mpctx,
};
mpctx->video_out = init_best_video_out(mpctx->global, &ex);
if (!mpctx->video_out) {
MP_FATAL(mpctx, "Error opening/initializing "
"the selected video_out (--vo) device.\n");
mpctx->error_playing = MPV_ERROR_VO_INIT_FAILED;
goto err_out;
}
mpctx->mouse_cursor_visible = true;
}
update_window_title(mpctx, true);
struct vo_chain *vo_c = talloc_zero(NULL, struct vo_chain);
mpctx->vo_chain = vo_c;
vo_c->log = mpctx->log;
vo_c->vo = mpctx->video_out;
vo_c->filter =
mp_output_chain_create(mpctx->filter_root, MP_OUTPUT_CHAIN_VIDEO);
mp_output_chain_set_vo(vo_c->filter, vo_c->vo);
vo_c->filter->update_subtitles = filter_update_subtitles;
vo_c->filter->update_subtitles_ctx = mpctx;
if (track) {
vo_c->track = track;
track->vo_c = vo_c;
if (!init_video_decoder(mpctx, track))
goto err_out;
vo_c->dec_src = track->dec->f->pins[0];
vo_c->filter->container_fps =
mp_decoder_wrapper_get_container_fps(track->dec);
vo_c->is_coverart = !!track->attached_picture;
vo_c->is_sparse = track->stream->still_image || vo_c->is_coverart;
if (vo_c->is_coverart)
mp_decoder_wrapper_set_coverart_flag(track->dec, true);
track->vo_c = vo_c;
vo_c->track = track;
mp_pin_connect(vo_c->filter->f->pins[0], vo_c->dec_src);
}
if (!recreate_video_filters(mpctx))
goto err_out;
update_content_type(mpctx, track);
update_screensaver_state(mpctx);
vo_set_paused(vo_c->vo, get_internal_paused(mpctx));
reset_video_state(mpctx);
term_osd_set_subs(mpctx, NULL);
return;
err_out:
uninit_video_chain(mpctx);
error_on_track(mpctx, track);
handle_force_window(mpctx, true);
}
// Try to refresh the video by doing a precise seek to the currently displayed
// frame. This can go wrong in all sorts of ways, so use sparingly.
void mp_force_video_refresh(struct MPContext *mpctx)
{
struct MPOpts *opts = mpctx->opts;
struct vo_chain *vo_c = mpctx->vo_chain;
if (!vo_c)
return;
// If not paused, the next frame should come soon enough.
if (opts->pause || mpctx->time_frame >= 0.5 ||
mpctx->video_status == STATUS_EOF)
{
issue_refresh_seek(mpctx, MPSEEK_VERY_EXACT);
}
}
static void check_framedrop(struct MPContext *mpctx, struct vo_chain *vo_c)
{
struct MPOpts *opts = mpctx->opts;
// check for frame-drop:
if (mpctx->video_status == STATUS_PLAYING && !mpctx->paused &&
mpctx->audio_status == STATUS_PLAYING && !ao_untimed(mpctx->ao) &&
vo_c->track && vo_c->track->dec && (opts->frame_dropping & 2))
{
float fps = vo_c->filter->container_fps;
// it's a crappy heuristic; avoid getting upset by incorrect fps
if (fps <= 20 || fps >= 500)
return;
double frame_time = 1.0 / fps;
// try to drop as many frames as we appear to be behind
mp_decoder_wrapper_set_frame_drops(vo_c->track->dec,
MPCLAMP((mpctx->last_av_difference - 0.010) / frame_time, 0, 100));
}
}
/* Modify video timing to match the audio timeline. There are two main
* reasons this is needed. First, video and audio can start from different
* positions at beginning of file or after a seek (MPlayer starts both
* immediately even if they have different pts). Second, the file can have
* audio timestamps that are inconsistent with the duration of the audio
* packets, for example two consecutive timestamp values differing by
* one second but only a packet with enough samples for half a second
* of playback between them.
*/
static void adjust_sync(struct MPContext *mpctx, double v_pts, double frame_time)
{
struct MPOpts *opts = mpctx->opts;
if (mpctx->audio_status != STATUS_PLAYING)
return;
double a_pts = written_audio_pts(mpctx) + opts->audio_delay - mpctx->delay;
double av_delay = a_pts - v_pts;
double change = av_delay * 0.1;
double factor = fabs(av_delay) < 0.3 ? 0.1 : 0.4;
double max_change = opts->default_max_pts_correction >= 0 ?
opts->default_max_pts_correction : frame_time * factor;
if (change < -max_change)
change = -max_change;
else if (change > max_change)
change = max_change;
mpctx->delay += change;
mpctx->total_avsync_change += change;
if (mpctx->display_sync_active)
mpctx->total_avsync_change = 0;
}
// Make the frame at position 0 "known" to the playback logic. This must happen
// only once for each frame, so this function has to be called carefully.
// Generally, if position 0 gets a new frame, this must be called.
static void handle_new_frame(struct MPContext *mpctx)
{
assert(mpctx->num_next_frames >= 1);
double frame_time = 0;
double pts = mpctx->next_frames[0]->pts;
bool is_sparse = mpctx->vo_chain && mpctx->vo_chain->is_sparse;
if (mpctx->video_pts != MP_NOPTS_VALUE) {
frame_time = pts - mpctx->video_pts;
double tolerance = mpctx->demuxer->ts_resets_possible &&
!is_sparse ? 5 : 1e4;
if (frame_time <= 0 || frame_time >= tolerance) {
// Assume a discontinuity.
MP_WARN(mpctx, "Invalid video timestamp: %f -> %f\n",
mpctx->video_pts, pts);
frame_time = 0;
}
}
mpctx->time_frame += frame_time / mpctx->video_speed;
if (mpctx->ao_chain && mpctx->ao_chain->audio_started)
mpctx->delay -= frame_time;
if (mpctx->video_status >= STATUS_PLAYING)
adjust_sync(mpctx, pts, frame_time);
MP_TRACE(mpctx, "frametime=%5.3f\n", frame_time);
}
// Remove the first frame in mpctx->next_frames
static void shift_frames(struct MPContext *mpctx)
{
if (mpctx->num_next_frames < 1)
return;
talloc_free(mpctx->next_frames[0]);
for (int n = 0; n < mpctx->num_next_frames - 1; n++)
mpctx->next_frames[n] = mpctx->next_frames[n + 1];
mpctx->num_next_frames -= 1;
}
static bool use_video_lookahead(struct MPContext *mpctx)
{
return mpctx->video_out &&
!(mpctx->video_out->driver->caps & VO_CAP_NORETAIN) &&
!(mpctx->opts->untimed || mpctx->video_out->driver->untimed) &&
!mpctx->opts->video_latency_hacks;
}
static int get_req_frames(struct MPContext *mpctx, bool eof)
{
// On EOF, drain all frames.
if (eof)
return 1;
if (!use_video_lookahead(mpctx))
return 1;
if (mpctx->vo_chain && mpctx->vo_chain->is_sparse)
return 1;
// Normally require at least 2 frames, so we can compute a frame duration.
int min = 2;
// On the first frame, output a new frame as quickly as possible.
if (mpctx->video_pts == MP_NOPTS_VALUE)
return min;
int req = vo_get_num_req_frames(mpctx->video_out);
return MPCLAMP(req, min, MP_ARRAY_SIZE(mpctx->next_frames) - 1);
}
// Whether it's fine to call add_new_frame() now.
static bool needs_new_frame(struct MPContext *mpctx)
{
return mpctx->num_next_frames < get_req_frames(mpctx, false);
}
// Queue a frame to mpctx->next_frames[]. Call only if needs_new_frame() signals ok.
static void add_new_frame(struct MPContext *mpctx, struct mp_image *frame)
{
assert(mpctx->num_next_frames < MP_ARRAY_SIZE(mpctx->next_frames));
assert(frame);
mpctx->next_frames[mpctx->num_next_frames++] = frame;
if (mpctx->num_next_frames == 1)
handle_new_frame(mpctx);
}
// Enough video filtered already to push one frame to the VO?
// Set eof to true if no new frames are to be expected.
static bool have_new_frame(struct MPContext *mpctx, bool eof)
{
return mpctx->num_next_frames >= get_req_frames(mpctx, eof);
}
// Fill mpctx->next_frames[] with a newly filtered or decoded image.
// logical_eof: is set to true if there is EOF after currently queued frames
// returns VD_* code
static int video_output_image(struct MPContext *mpctx, bool *logical_eof)
{
struct vo_chain *vo_c = mpctx->vo_chain;
bool hrseek = false;
double hrseek_pts = mpctx->hrseek_pts;
double tolerance = mpctx->hrseek_backstep ? 0 : .005;
if (mpctx->video_status == STATUS_SYNCING) {
hrseek = mpctx->hrseek_active;
// playback_pts is normally only set when audio and video have started
// playing normally. If video is in syncing mode, then this must mean
// video was just enabled via track switching - skip to current time.
if (!hrseek && mpctx->playback_pts != MP_NOPTS_VALUE) {
hrseek = true;
hrseek_pts = mpctx->playback_pts;
}
}
if (vo_c->is_coverart) {
*logical_eof = true;
if (vo_has_frame(mpctx->video_out))
return VD_EOF;
hrseek = false;
}
if (have_new_frame(mpctx, false))
return VD_NEW_FRAME;
// Get a new frame if we need one.
int r = VD_PROGRESS;
if (needs_new_frame(mpctx)) {
// Filter a new frame.
struct mp_image *img = NULL;
struct mp_frame frame = mp_pin_out_read(vo_c->filter->f->pins[1]);
if (frame.type == MP_FRAME_NONE) {
r = vo_c->filter->got_output_eof ? VD_EOF : VD_WAIT;
} else if (frame.type == MP_FRAME_EOF) {
r = VD_EOF;
} else if (frame.type == MP_FRAME_VIDEO) {
img = frame.data;
} else {
MP_ERR(mpctx, "unexpected frame type %s\n",
mp_frame_type_str(frame.type));
mp_frame_unref(&frame);
return VD_ERROR;
}
if (img) {
double endpts = get_play_end_pts(mpctx);
if (endpts != MP_NOPTS_VALUE)
endpts *= mpctx->play_dir;
if ((endpts != MP_NOPTS_VALUE && img->pts >= endpts) ||
mpctx->max_frames == 0)
{
mp_pin_out_unread(vo_c->filter->f->pins[1], frame);
img = NULL;
r = VD_EOF;
} else if (hrseek && (img->pts < hrseek_pts - tolerance ||
mpctx->hrseek_lastframe))
{
/* just skip - but save in case it was the last frame */
mp_image_setrefp(&mpctx->saved_frame, img);
} else {
if (hrseek && mpctx->hrseek_backstep) {
if (mpctx->saved_frame) {
add_new_frame(mpctx, mpctx->saved_frame);
mpctx->saved_frame = NULL;
} else {
MP_WARN(mpctx, "Backstep failed.\n");
}
mpctx->hrseek_backstep = false;
}
mp_image_unrefp(&mpctx->saved_frame);
add_new_frame(mpctx, img);
img = NULL;
}
talloc_free(img);
}
}
if (!hrseek)
mp_image_unrefp(&mpctx->saved_frame);
if (r == VD_EOF) {
// If hr-seek went past EOF, use the last frame.
if (mpctx->saved_frame)
add_new_frame(mpctx, mpctx->saved_frame);
mpctx->saved_frame = NULL;
*logical_eof = true;
}
return have_new_frame(mpctx, r <= 0) ? VD_NEW_FRAME : r;
}
static bool check_for_hwdec_fallback(struct MPContext *mpctx)
{
struct vo_chain *vo_c = mpctx->vo_chain;
if (!vo_c->filter->failed_output_conversion || !vo_c->track || !vo_c->track->dec)
return false;
if (mp_decoder_wrapper_control(vo_c->track->dec,
VDCTRL_FORCE_HWDEC_FALLBACK, NULL) != CONTROL_OK)
return false;
mp_output_chain_reset_harder(vo_c->filter);
return true;
}
static bool check_for_forced_eof(struct MPContext *mpctx)
{
struct vo_chain *vo_c = mpctx->vo_chain;
if (!vo_c->track || !vo_c->track->dec)
return false;
struct mp_decoder_wrapper *dec = vo_c->track->dec;
bool forced_eof = false;
mp_decoder_wrapper_control(dec, VDCTRL_CHECK_FORCED_EOF, &forced_eof);
return forced_eof;
}
/* Update avsync before a new video frame is displayed. Actually, this can be
* called arbitrarily often before the actual display.
* This adjusts the time of the next video frame */
static void update_avsync_before_frame(struct MPContext *mpctx)
{
struct MPOpts *opts = mpctx->opts;
struct vo *vo = mpctx->video_out;
if (mpctx->video_status < STATUS_READY) {
mpctx->time_frame = 0;
} else if (mpctx->display_sync_active || vo->opts->video_sync == VS_NONE) {
// don't touch the timing
} else if (mpctx->audio_status == STATUS_PLAYING &&
mpctx->video_status == STATUS_PLAYING &&
!ao_untimed(mpctx->ao))
{
double buffered_audio = ao_get_delay(mpctx->ao);
double predicted = mpctx->delay / mpctx->video_speed +
mpctx->time_frame;
double difference = buffered_audio - predicted;
MP_STATS(mpctx, "value %f audio-diff", difference);
if (opts->autosync) {
/* Smooth reported playback position from AO by averaging
* it with the value expected based on previous value and
* time elapsed since then. May help smooth video timing
* with audio output that have inaccurate position reporting.
* This is badly implemented; the behavior of the smoothing
* now undesirably depends on how often this code runs
* (mainly depends on video frame rate). */
buffered_audio = predicted + difference / opts->autosync;
}
mpctx->time_frame = buffered_audio - mpctx->delay / mpctx->video_speed;
} else {
/* If we're more than 200 ms behind the right playback
* position, don't try to speed up display of following
* frames to catch up; continue with default speed from
* the current frame instead.
* If untimed is set always output frames immediately
* without sleeping.
*/
if (mpctx->time_frame < -0.2 || opts->untimed || vo->driver->untimed)
mpctx->time_frame = 0;
}
}
// Update the A/V sync difference when a new video frame is being shown.
static void update_av_diff(struct MPContext *mpctx, double offset)
{
struct MPOpts *opts = mpctx->opts;
mpctx->last_av_difference = 0;
if (mpctx->audio_status != STATUS_PLAYING ||
mpctx->video_status != STATUS_PLAYING)
return;
if (mpctx->vo_chain && mpctx->vo_chain->is_sparse)
return;
double a_pos = written_audio_pts(mpctx);
if (a_pos != MP_NOPTS_VALUE && mpctx->video_pts != MP_NOPTS_VALUE) {
a_pos -= mpctx->audio_speed * ao_get_delay(mpctx->ao);
mpctx->last_av_difference = a_pos - mpctx->video_pts
+ opts->audio_delay + offset;
}
if (fabs(mpctx->last_av_difference) > 0.5 && !mpctx->drop_message_shown) {
MP_WARN(mpctx, "%s", av_desync_help_text);
mpctx->drop_message_shown = true;
}
}
double calc_average_frame_duration(struct MPContext *mpctx)
{
double total = 0;
int num = 0;
for (int n = 0; n < mpctx->num_past_frames; n++) {
double dur = mpctx->past_frames[n].approx_duration;
if (dur <= 0)
continue;
total += dur;
num += 1;
}
return num > 0 ? total / num : 0;
}
// Find a speed factor such that the display FPS is an integer multiple of the
// effective video FPS. If this is not possible, try to do it for multiples,
// which still leads to an improved end result.
// Both parameters are durations in seconds.
static double calc_best_speed(double vsync, double frame,
double max_change, int max_factor)
{
double ratio = frame / vsync;
for (int factor = 1; factor <= max_factor; factor++) {
double scale = ratio * factor / rint(ratio * factor);
if (fabs(scale - 1) <= max_change)
return scale;
}
return -1;
}
static double find_best_speed(struct MPContext *mpctx, double vsync)
{
double total = 0;
int num = 0;
for (int n = 0; n < mpctx->num_past_frames; n++) {
double dur = mpctx->past_frames[n].approx_duration;
if (dur <= 0)
continue;
double best = calc_best_speed(vsync, dur / mpctx->opts->playback_speed,
mpctx->opts->sync_max_video_change / 100,
mpctx->opts->sync_max_factor);
if (best <= 0)
continue;
total += best;
num++;
}
// If it doesn't work, play at normal speed.
return num > 0 ? total / num : 1;
}
static bool using_spdif_passthrough(struct MPContext *mpctx)
{
if (mpctx->ao_chain && mpctx->ao_chain->ao) {
int samplerate;
int format;
struct mp_chmap channels;
ao_get_format(mpctx->ao_chain->ao, &samplerate, &format, &channels);
return !af_fmt_is_pcm(format);
}
return false;
}
// Compute the relative audio speed difference by taking A/V dsync into account.
static double compute_audio_drift(struct MPContext *mpctx, double vsync)
{
// Least-squares linear regression, using relative real time for x, and
// audio desync for y. Assume speed didn't change for the frames we're
// looking at for simplicity. This also should actually use the realtime
// (minus paused time) for x, but use vsync scheduling points instead.
if (mpctx->num_past_frames <= 10)
return NAN;
int num = mpctx->num_past_frames - 1;
double sum_x = 0, sum_y = 0, sum_xy = 0, sum_xx = 0;
double x = 0;
for (int n = 0; n < num; n++) {
struct frame_info *frame = &mpctx->past_frames[n + 1];
if (frame->num_vsyncs < 0)
return NAN;
double y = frame->av_diff;
sum_x += x;
sum_y += y;
sum_xy += x * y;
sum_xx += x * x;
x -= frame->num_vsyncs * vsync;
}
return (sum_x * sum_y - num * sum_xy) / (sum_x * sum_x - num * sum_xx);
}
static void adjust_audio_drift_compensation(struct MPContext *mpctx, double vsync)
{
struct MPOpts *opts = mpctx->opts;
int mode = mpctx->video_out->opts->video_sync;
if ((mode != VS_DISP_RESAMPLE && mode != VS_DISP_TEMPO) ||
mpctx->audio_status != STATUS_PLAYING)
{
mpctx->speed_factor_a = mpctx->speed_factor_v;
return;
}
// Try to smooth out audio timing drifts. This can happen if either
// video isn't playing at expected speed, or audio is not playing at
// the requested speed. Both are unavoidable.
// The audio desync is made up of 2 parts: 1. drift due to rounding
// errors and imperfect information, and 2. an offset, due to
// unaligned audio/video start, or disruptive events halting audio
// or video for a small time.
// Instead of trying to be clever, just apply an awfully dumb drift
// compensation with a constant factor, which does what we want. In
// theory we could calculate the exact drift compensation needed,
// but it likely would be wrong anyway, and we'd run into the same
// issues again, except with more complex code.
// 1 means drifts to positive, -1 means drifts to negative
double max_drift = vsync / 2;
double av_diff = mpctx->last_av_difference;
int new = mpctx->display_sync_drift_dir;
if (av_diff * -mpctx->display_sync_drift_dir >= 0)
new = 0;
if (fabs(av_diff) > max_drift)
new = av_diff >= 0 ? 1 : -1;
bool change = mpctx->display_sync_drift_dir != new;
if (new || change) {
if (change)
MP_VERBOSE(mpctx, "Change display sync audio drift: %d\n", new);
mpctx->display_sync_drift_dir = new;
double max_correct = opts->sync_max_audio_change / 100;
double audio_factor = 1 + max_correct * -mpctx->display_sync_drift_dir;
if (new == 0) {
// If we're resetting, actually try to be clever and pick a speed
// which compensates the general drift we're getting.
double drift = compute_audio_drift(mpctx, vsync);
if (isnormal(drift)) {
// other = will be multiplied with audio_factor for final speed
double other = mpctx->opts->playback_speed * mpctx->speed_factor_v;
audio_factor = (mpctx->audio_speed - drift) / other;
MP_VERBOSE(mpctx, "Compensation factor: %f\n", audio_factor);
}
}
audio_factor = MPCLAMP(audio_factor, 1 - max_correct, 1 + max_correct);
mpctx->speed_factor_a = audio_factor * mpctx->speed_factor_v;
}
}
// Manipulate frame timing for display sync, or do nothing for normal timing.
static void handle_display_sync_frame(struct MPContext *mpctx,
struct vo_frame *frame)
{
struct MPOpts *opts = mpctx->opts;
struct vo *vo = mpctx->video_out;
int mode = vo->opts->video_sync;
if (!mpctx->display_sync_active) {
mpctx->display_sync_error = 0.0;
mpctx->display_sync_drift_dir = 0;
}
mpctx->display_sync_active = false;
if (!VS_IS_DISP(mode))
return;
bool resample = mode == VS_DISP_RESAMPLE || mode == VS_DISP_RESAMPLE_VDROP ||
mode == VS_DISP_RESAMPLE_NONE;
bool drop = mode == VS_DISP_VDROP || mode == VS_DISP_RESAMPLE ||
mode == VS_DISP_ADROP || mode == VS_DISP_RESAMPLE_VDROP ||
mode == VS_DISP_TEMPO;
drop &= frame->can_drop;
if (resample && using_spdif_passthrough(mpctx))
return;
double vsync = vo_get_vsync_interval(vo) / 1e9;
if (vsync <= 0)
return;
double approx_duration = MPMAX(0, mpctx->past_frames[0].approx_duration);
double adjusted_duration = approx_duration / opts->playback_speed;
if (adjusted_duration > 0.5)
return;
mpctx->speed_factor_v = 1.0;
if (mode != VS_DISP_VDROP)
mpctx->speed_factor_v = find_best_speed(mpctx, vsync);
// Determine for how many vsyncs a frame should be displayed. This can be
// e.g. 2 for 30hz on a 60hz display. It can also be 0 if the video
// framerate is higher than the display framerate.
// We use the speed-adjusted (i.e. real) frame duration for this.
double frame_duration = adjusted_duration / mpctx->speed_factor_v;
double ratio = (frame_duration + mpctx->display_sync_error) / vsync;
int num_vsyncs = MPMAX(lrint(ratio), 0);
double prev_error = mpctx->display_sync_error;
mpctx->display_sync_error += frame_duration - num_vsyncs * vsync;
MP_TRACE(mpctx, "s=%f vsyncs=%d dur=%f ratio=%f err=%.20f (%f/%f)\n",
mpctx->speed_factor_v, num_vsyncs, adjusted_duration, ratio,
mpctx->display_sync_error, mpctx->display_sync_error / vsync,
mpctx->display_sync_error / frame_duration);
double av_diff = mpctx->last_av_difference;
MP_STATS(mpctx, "value %f avdiff", av_diff);
// Intended number of additional display frames to drop (<0) or repeat (>0)
int drop_repeat = 0;
// If we are too far ahead/behind, attempt to drop/repeat frames.
// Tolerate some desync to avoid frame dropping due to jitter.
if (drop && fabs(av_diff) >= 0.020 && fabs(av_diff) / vsync >= 1)
drop_repeat = -av_diff / vsync; // round towards 0
// We can only drop all frames at most. We can repeat much more frames,
// but we still limit it to 10 times the original frames to avoid that
// corner cases or exceptional situations cause too much havoc.
drop_repeat = MPCLAMP(drop_repeat, -num_vsyncs, num_vsyncs * 10);
num_vsyncs += drop_repeat;
// Always show the first frame.
if (mpctx->num_past_frames <= 1 && num_vsyncs < 1)
num_vsyncs = 1;
// Estimate the video position, so we can calculate a good A/V difference
// value below. This is used to estimate A/V drift.
double time_left = vo_get_delay(vo);
// We also know that the timing is (necessarily) off, because we have to
// align frame timings on the vsync boundaries. This is unavoidable, and
// for the sake of the A/V sync calculations we pretend it's perfect.
time_left += prev_error;
// Likewise, we know sync is off, but is going to be compensated.
time_left += drop_repeat * vsync;
// If syncing took too long, disregard timing of the first frame.
if (mpctx->num_past_frames == 2 && time_left < 0) {
vo_discard_timing_info(vo);
time_left = 0;
}
if (drop_repeat) {
mpctx->mistimed_frames_total += 1;
MP_STATS(mpctx, "mistimed");
}
mpctx->total_avsync_change = 0;
update_av_diff(mpctx, time_left * opts->playback_speed);
mpctx->past_frames[0].num_vsyncs = num_vsyncs;
mpctx->past_frames[0].av_diff = mpctx->last_av_difference;
if (resample || mode == VS_DISP_ADROP || mode == VS_DISP_TEMPO) {
adjust_audio_drift_compensation(mpctx, vsync);
} else {
mpctx->speed_factor_a = 1.0;
}
// A bad guess, only needed when reverting to audio sync.
mpctx->time_frame = time_left;
frame->vsync_interval = vsync;
frame->vsync_offset = -prev_error;
frame->ideal_frame_duration = frame_duration;
frame->ideal_frame_vsync = (-prev_error / frame_duration) * approx_duration;
frame->ideal_frame_vsync_duration = (vsync / frame_duration) * approx_duration;
frame->num_vsyncs = num_vsyncs;
frame->display_synced = true;
frame->approx_duration = approx_duration;
// Adjust frame virtual vsyncs by the repeat count
if (drop_repeat > 0)
frame->ideal_frame_vsync_duration /= drop_repeat;
mpctx->display_sync_active = true;
// Try to avoid audio underruns that may occur if we update
// the playback speed while in the STATUS_SYNCING state.
if (mpctx->video_status != STATUS_SYNCING)
update_playback_speed(mpctx);
MP_STATS(mpctx, "value %f aspeed", mpctx->speed_factor_a - 1);
MP_STATS(mpctx, "value %f vspeed", mpctx->speed_factor_v - 1);
}
static void schedule_frame(struct MPContext *mpctx, struct vo_frame *frame)
{
handle_display_sync_frame(mpctx, frame);
if (mpctx->num_past_frames > 1 &&
((mpctx->past_frames[1].num_vsyncs >= 0) != mpctx->display_sync_active))
{
MP_VERBOSE(mpctx, "Video sync mode %s.\n",
mpctx->display_sync_active ? "enabled" : "disabled");
}
if (!mpctx->display_sync_active) {
mpctx->speed_factor_a = 1.0;
mpctx->speed_factor_v = 1.0;
update_playback_speed(mpctx);
update_av_diff(mpctx, mpctx->time_frame > 0 ?
mpctx->time_frame * mpctx->video_speed : 0);
}
}
// Determine the mpctx->past_frames[0] frame duration.
static void calculate_frame_duration(struct MPContext *mpctx)
{
struct vo_chain *vo_c = mpctx->vo_chain;
assert(mpctx->num_past_frames >= 1 && mpctx->num_next_frames >= 1);
double demux_duration = vo_c->filter->container_fps > 0
? 1.0 / vo_c->filter->container_fps : -1;
double duration = demux_duration;
if (mpctx->num_next_frames >= 2) {
double pts0 = mpctx->next_frames[0]->pts;
double pts1 = mpctx->next_frames[1]->pts;
if (pts0 != MP_NOPTS_VALUE && pts1 != MP_NOPTS_VALUE && pts1 >= pts0)
duration = pts1 - pts0;
}
// The following code tries to compensate for rounded Matroska timestamps
// by "unrounding" frame durations, or if not possible, approximating them.
// These formats usually round on 1ms. Some muxers do this incorrectly,
// and might go off by 1ms more, and compensate for it later by an equal
// rounding error into the opposite direction.
double tolerance = 0.001 * 3 + 0.0001;
double total = 0;
int num_dur = 0;
for (int n = 1; n < mpctx->num_past_frames; n++) {
// Eliminate likely outliers using a really dumb heuristic.
double dur = mpctx->past_frames[n].duration;
if (dur <= 0 || fabs(dur - duration) >= tolerance)
break;
total += dur;
num_dur += 1;
}
double approx_duration = num_dur > 0 ? total / num_dur : duration;