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mpv/video/out/vo_lavc.c
wm4 793b43020c vo_lavc: remove messy delayed subtitle rendering logic 
For some reason vo_lavc's draw_image can buffer the frame and encode it
only later. Also, there is logic for rendering the OSD (i.e. subtitles)
only when needed.

In theory this can lead to subtitles being pruned before it tries to
render them (as the subtitle logic doesn't know that the VO still needs
them later), although this probably never happens in reality.

The worse issue, that actually happened, is that if the last frame gets
buffered, it attempts to render subtitles in the uninit callback. At
this point, the subtitle decoder is already torn down and all subtitles
removed, thus it will draw nothing. This didn't always happen. I'm not
sure why - potentially in the working cases, the frame wasn't buffered.

Since this logic doesn't have much worth, except a minor performance
advantage if frames with subtitles are dropped, just remove it.

Hopefully fixes #4689.
2017-11-07 05:29:26 +01:00

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/*
* video encoding using libavformat
*
* Copyright (C) 2010 Nicolas George <george@nsup.org>
* Copyright (C) 2011-2012 Rudolf Polzer <divVerent@xonotic.org>
*
* 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 <stdio.h>
#include <stdlib.h>
#include "config.h"
#include "common/common.h"
#include "options/options.h"
#include "video/fmt-conversion.h"
#include "video/mp_image.h"
#include "mpv_talloc.h"
#include "vo.h"
#include "common/encode_lavc.h"
#include "sub/osd.h"
struct priv {
AVStream *stream;
AVCodecContext *codec;
int have_first_packet;
int harddup;
double lastpts;
int64_t lastipts;
int64_t lastframeipts;
int64_t lastencodedipts;
int64_t mindeltapts;
double expected_next_pts;
mp_image_t *lastimg;
int lastdisplaycount;
AVRational worst_time_base;
int worst_time_base_is_stream;
bool shutdown;
};
static int preinit(struct vo *vo)
{
struct priv *vc;
if (!encode_lavc_available(vo->encode_lavc_ctx)) {
MP_ERR(vo, "the option --o (output file) must be specified\n");
return -1;
}
vo->priv = talloc_zero(vo, struct priv);
vc = vo->priv;
vc->harddup = vo->encode_lavc_ctx->options->harddup;
return 0;
}
static void draw_image_unlocked(struct vo *vo, mp_image_t *mpi);
static void uninit(struct vo *vo)
{
struct priv *vc = vo->priv;
if (!vc || vc->shutdown)
return;
pthread_mutex_lock(&vo->encode_lavc_ctx->lock);
if (vc->lastipts >= 0 && vc->stream)
draw_image_unlocked(vo, NULL);
mp_image_unrefp(&vc->lastimg);
pthread_mutex_unlock(&vo->encode_lavc_ctx->lock);
vc->shutdown = true;
}
static int reconfig(struct vo *vo, struct mp_image_params *params)
{
struct priv *vc = vo->priv;
enum AVPixelFormat pix_fmt = imgfmt2pixfmt(params->imgfmt);
AVRational aspect = {params->p_w, params->p_h};
uint32_t width = params->w;
uint32_t height = params->h;
if (!vc || vc->shutdown)
return -1;
pthread_mutex_lock(&vo->encode_lavc_ctx->lock);
if (vc->stream) {
/* NOTE:
* in debug builds we get a "comparison between signed and unsigned"
* warning here. We choose to ignore that; just because ffmpeg currently
* uses a plain 'int' for these struct fields, it doesn't mean it always
* will */
if (width == vc->codec->width &&
height == vc->codec->height) {
if (aspect.num != vc->codec->sample_aspect_ratio.num ||
aspect.den != vc->codec->sample_aspect_ratio.den) {
/* aspect-only changes are not critical */
MP_WARN(vo, "unsupported pixel aspect ratio change from %d:%d to %d:%d\n",
vc->codec->sample_aspect_ratio.num,
vc->codec->sample_aspect_ratio.den,
aspect.num, aspect.den);
}
goto done;
}
/* FIXME Is it possible with raw video? */
MP_ERR(vo, "resolution changes not supported.\n");
goto error;
}
// When we get here, this must be the first call to reconfigure(). Thus, we
// can rely on no existing data in vc having been allocated yet.
// Reason:
// - Second calls after reconfigure() already failed once fail (due to the
// vc->shutdown check above).
// - Second calls after reconfigure() already succeeded once return early
// (due to the vc->stream check above).
vc->lastipts = AV_NOPTS_VALUE;
vc->lastframeipts = AV_NOPTS_VALUE;
vc->lastencodedipts = AV_NOPTS_VALUE;
if (pix_fmt == AV_PIX_FMT_NONE) {
MP_FATAL(vo, "Format %s not supported by lavc.\n",
mp_imgfmt_to_name(params->imgfmt));
goto error;
}
if (encode_lavc_alloc_stream(vo->encode_lavc_ctx,
AVMEDIA_TYPE_VIDEO,
&vc->stream, &vc->codec) < 0)
goto error;
vc->stream->sample_aspect_ratio = vc->codec->sample_aspect_ratio =
aspect;
vc->codec->width = width;
vc->codec->height = height;
vc->codec->pix_fmt = pix_fmt;
encode_lavc_set_csp(vo->encode_lavc_ctx, vc->codec, params->color.space);
encode_lavc_set_csp_levels(vo->encode_lavc_ctx, vc->codec, params->color.levels);
if (encode_lavc_open_codec(vo->encode_lavc_ctx, vc->codec) < 0)
goto error;
done:
pthread_mutex_unlock(&vo->encode_lavc_ctx->lock);
return 0;
error:
pthread_mutex_unlock(&vo->encode_lavc_ctx->lock);
vc->shutdown = true;
return -1;
}
static int query_format(struct vo *vo, int format)
{
enum AVPixelFormat pix_fmt = imgfmt2pixfmt(format);
if (!vo->encode_lavc_ctx)
return 0;
pthread_mutex_lock(&vo->encode_lavc_ctx->lock);
int flags = 0;
if (encode_lavc_supports_pixfmt(vo->encode_lavc_ctx, pix_fmt))
flags = 1;
pthread_mutex_unlock(&vo->encode_lavc_ctx->lock);
return flags;
}
static void write_packet(struct vo *vo, AVPacket *packet)
{
struct priv *vc = vo->priv;
packet->stream_index = vc->stream->index;
if (packet->pts != AV_NOPTS_VALUE) {
packet->pts = av_rescale_q(packet->pts,
vc->codec->time_base,
vc->stream->time_base);
} else {
MP_VERBOSE(vo, "codec did not provide pts\n");
packet->pts = av_rescale_q(vc->lastipts,
vc->worst_time_base,
vc->stream->time_base);
}
if (packet->dts != AV_NOPTS_VALUE) {
packet->dts = av_rescale_q(packet->dts,
vc->codec->time_base,
vc->stream->time_base);
}
if (packet->duration > 0) {
packet->duration = av_rescale_q(packet->duration,
vc->codec->time_base,
vc->stream->time_base);
} else {
// HACK: libavformat calculates dts wrong if the initial packet
// duration is not set, but ONLY if the time base is "high" and if we
// have b-frames!
if (!packet->duration)
if (!vc->have_first_packet)
if (vc->codec->has_b_frames
|| vc->codec->max_b_frames)
if (vc->stream->time_base.num * 1000LL <=
vc->stream->time_base.den)
packet->duration = FFMAX(1, av_rescale_q(1,
vc->codec->time_base, vc->stream->time_base));
}
if (encode_lavc_write_frame(vo->encode_lavc_ctx,
vc->stream, packet) < 0) {
MP_ERR(vo, "error writing at %d %d/%d\n",
(int) packet->pts,
vc->stream->time_base.num,
vc->stream->time_base.den);
return;
}
vc->have_first_packet = 1;
}
static void encode_video_and_write(struct vo *vo, AVFrame *frame)
{
struct priv *vc = vo->priv;
AVPacket packet = {0};
int status = avcodec_send_frame(vc->codec, frame);
if (status < 0) {
MP_ERR(vo, "error encoding at %d %d/%d\n",
frame ? (int) frame->pts : -1,
vc->codec->time_base.num,
vc->codec->time_base.den);
return;
}
for (;;) {
av_init_packet(&packet);
status = avcodec_receive_packet(vc->codec, &packet);
if (status == AVERROR(EAGAIN)) { // No more packets for now.
if (frame == NULL) {
MP_ERR(vo, "sent flush frame, got EAGAIN");
}
break;
}
if (status == AVERROR_EOF) { // No more packets, ever.
if (frame != NULL) {
MP_ERR(vo, "sent image frame, got EOF");
}
break;
}
if (status < 0) {
MP_ERR(vo, "error encoding at %d %d/%d\n",
frame ? (int) frame->pts : -1,
vc->codec->time_base.num,
vc->codec->time_base.den);
break;
}
encode_lavc_write_stats(vo->encode_lavc_ctx, vc->codec);
write_packet(vo, &packet);
av_packet_unref(&packet);
}
}
static void draw_image_unlocked(struct vo *vo, mp_image_t *mpi)
{
struct priv *vc = vo->priv;
struct encode_lavc_context *ectx = vo->encode_lavc_ctx;
AVCodecContext *avc;
int64_t frameipts;
double nextpts;
double pts = mpi ? mpi->pts : MP_NOPTS_VALUE;
if (mpi) {
assert(vo->params);
struct mp_osd_res dim = osd_res_from_image_params(vo->params);
osd_draw_on_image(vo->osd, dim, mpi->pts, OSD_DRAW_SUB_ONLY, mpi);
}
if (!vc || vc->shutdown)
goto done;
if (!encode_lavc_start(ectx)) {
MP_WARN(vo, "NOTE: skipped initial video frame (probably because audio is not there yet)\n");
goto done;
}
if (pts == MP_NOPTS_VALUE) {
if (mpi)
MP_WARN(vo, "frame without pts, please report; synthesizing pts instead\n");
pts = vc->expected_next_pts;
}
avc = vc->codec;
if (vc->worst_time_base.den == 0) {
//if (avc->time_base.num / avc->time_base.den >= vc->stream->time_base.num / vc->stream->time_base.den)
if (avc->time_base.num * (double) vc->stream->time_base.den >=
vc->stream->time_base.num * (double) avc->time_base.den) {
MP_VERBOSE(vo, "NOTE: using codec time base "
"(%d/%d) for frame dropping; the stream base (%d/%d) is "
"not worse.\n", (int)avc->time_base.num,
(int)avc->time_base.den, (int)vc->stream->time_base.num,
(int)vc->stream->time_base.den);
vc->worst_time_base = avc->time_base;
vc->worst_time_base_is_stream = 0;
} else {
MP_WARN(vo, "NOTE: not using codec time base (%d/%d) for frame "
"dropping; the stream base (%d/%d) is worse.\n",
(int)avc->time_base.num, (int)avc->time_base.den,
(int)vc->stream->time_base.num, (int)vc->stream->time_base.den);
vc->worst_time_base = vc->stream->time_base;
vc->worst_time_base_is_stream = 1;
}
if (ectx->options->maxfps)
vc->mindeltapts = ceil(vc->worst_time_base.den /
(vc->worst_time_base.num * ectx->options->maxfps));
else
vc->mindeltapts = 0;
// NOTE: we use the following "axiom" of av_rescale_q:
// if time base A is worse than time base B, then
// av_rescale_q(av_rescale_q(x, A, B), B, A) == x
// this can be proven as long as av_rescale_q rounds to nearest, which
// it currently does
// av_rescale_q(x, A, B) * B = "round x*A to nearest multiple of B"
// and:
// av_rescale_q(av_rescale_q(x, A, B), B, A) * A
// == "round av_rescale_q(x, A, B)*B to nearest multiple of A"
// == "round 'round x*A to nearest multiple of B' to nearest multiple of A"
//
// assume this fails. Then there is a value of x*A, for which the
// nearest multiple of B is outside the range [(x-0.5)*A, (x+0.5)*A[.
// Absurd, as this range MUST contain at least one multiple of B.
}
double timeunit = (double)vc->worst_time_base.num / vc->worst_time_base.den;
double outpts;
if (ectx->options->rawts)
outpts = pts;
else if (ectx->options->copyts) {
// fix the discontinuity pts offset
nextpts = pts;
if (ectx->discontinuity_pts_offset == MP_NOPTS_VALUE) {
ectx->discontinuity_pts_offset = ectx->next_in_pts - nextpts;
}
else if (fabs(nextpts + ectx->discontinuity_pts_offset - ectx->next_in_pts) > 30) {
MP_WARN(vo, "detected an unexpected discontinuity (pts jumped by "
"%f seconds)\n",
nextpts + ectx->discontinuity_pts_offset - ectx->next_in_pts);
ectx->discontinuity_pts_offset = ectx->next_in_pts - nextpts;
}
outpts = pts + ectx->discontinuity_pts_offset;
}
else {
// adjust pts by knowledge of audio pts vs audio playback time
double duration = 0;
if (ectx->last_video_in_pts != MP_NOPTS_VALUE)
duration = pts - ectx->last_video_in_pts;
if (duration < 0)
duration = timeunit; // XXX warn about discontinuity?
outpts = vc->lastpts + duration;
if (ectx->audio_pts_offset != MP_NOPTS_VALUE) {
double adj = outpts - pts - ectx->audio_pts_offset;
adj = FFMIN(adj, duration * 0.1);
adj = FFMAX(adj, -duration * 0.1);
outpts -= adj;
}
}
vc->lastpts = outpts;
ectx->last_video_in_pts = pts;
frameipts = floor((outpts + encode_lavc_getoffset(ectx, vc->codec))
/ timeunit + 0.5);
// calculate expected pts of next video frame
vc->expected_next_pts = pts + timeunit;
if (!ectx->options->rawts && ectx->options->copyts) {
// set next allowed output pts value
nextpts = vc->expected_next_pts + ectx->discontinuity_pts_offset;
if (nextpts > ectx->next_in_pts)
ectx->next_in_pts = nextpts;
}
// never-drop mode
if (ectx->options->neverdrop) {
int64_t step = vc->mindeltapts ? vc->mindeltapts : 1;
if (frameipts < vc->lastipts + step) {
MP_INFO(vo, "--oneverdrop increased pts by %d\n",
(int) (vc->lastipts - frameipts + step));
frameipts = vc->lastipts + step;
vc->lastpts = frameipts * timeunit - encode_lavc_getoffset(ectx, vc->codec);
}
}
if (vc->lastipts != AV_NOPTS_VALUE) {
// we have a valid image in lastimg
while (vc->lastimg && vc->lastipts < frameipts) {
int64_t thisduration = vc->harddup ? 1 : (frameipts - vc->lastipts);
// we will ONLY encode this frame if it can be encoded at at least
// vc->mindeltapts after the last encoded frame!
int64_t skipframes =
(vc->lastencodedipts == AV_NOPTS_VALUE)
? 0
: vc->lastencodedipts + vc->mindeltapts - vc->lastipts;
if (skipframes < 0)
skipframes = 0;
if (thisduration > skipframes) {
AVFrame *frame = mp_image_to_av_frame(vc->lastimg);
if (!frame)
abort();
// this is a nop, unless the worst time base is the STREAM time base
frame->pts = av_rescale_q(vc->lastipts + skipframes,
vc->worst_time_base, avc->time_base);
frame->pict_type = 0; // keep this at unknown/undefined
frame->quality = avc->global_quality;
encode_video_and_write(vo, frame);
av_frame_free(&frame);
++vc->lastdisplaycount;
vc->lastencodedipts = vc->lastipts + skipframes;
}
vc->lastipts += thisduration;
}
}
if (!mpi) {
// finish encoding
encode_video_and_write(vo, NULL);
} else {
if (frameipts >= vc->lastframeipts) {
if (vc->lastframeipts != AV_NOPTS_VALUE && vc->lastdisplaycount != 1)
MP_INFO(vo, "Frame at pts %d got displayed %d times\n",
(int) vc->lastframeipts, vc->lastdisplaycount);
talloc_free(vc->lastimg);
vc->lastimg = mpi;
mpi = NULL;
vc->lastframeipts = vc->lastipts = frameipts;
if (ectx->options->rawts && vc->lastipts < 0) {
MP_ERR(vo, "why does this happen? DEBUG THIS! vc->lastipts = %lld\n", (long long) vc->lastipts);
vc->lastipts = -1;
}
vc->lastdisplaycount = 0;
} else {
MP_INFO(vo, "Frame at pts %d got dropped "
"entirely because pts went backwards\n", (int) frameipts);
}
}
done:
talloc_free(mpi);
}
static void draw_image(struct vo *vo, mp_image_t *mpi)
{
pthread_mutex_lock(&vo->encode_lavc_ctx->lock);
draw_image_unlocked(vo, mpi);
pthread_mutex_unlock(&vo->encode_lavc_ctx->lock);
}
static void flip_page(struct vo *vo)
{
}
static int control(struct vo *vo, uint32_t request, void *data)
{
return VO_NOTIMPL;
}
const struct vo_driver video_out_lavc = {
.encode = true,
.description = "video encoding using libavcodec",
.name = "lavc",
.untimed = true,
.preinit = preinit,
.query_format = query_format,
.reconfig = reconfig,
.control = control,
.uninit = uninit,
.draw_image = draw_image,
.flip_page = flip_page,
};
// vim: sw=4 ts=4 et tw=80
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