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fftools_sync_queue.c
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/*
* This file is part of FFmpeg.
* Copyright (c) 2023 ARTHENICA LTD
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*
* This file is the modified version of sync_queue.c file living in ffmpeg source code under the fftools folder. We
* manually update it each time we depend on a new ffmpeg version. Below you can see the list of changes applied
* by us to develop ffmpeg-kit library.
*
* ffmpeg-kit changes by ARTHENICA LTD
*
* 07.2023
* --------------------------------------------------------
* - FFmpeg 6.0 changes migrated
* - fftools header names updated
*/
#include <stdint.h>
#include <string.h>
#include "libavutil/avassert.h"
#include "libavutil/error.h"
#include "libavutil/fifo.h"
#include "libavutil/mathematics.h"
#include "libavutil/mem.h"
#include "fftools_objpool.h"
#include "fftools_sync_queue.h"
typedef struct SyncQueueStream {
AVFifo *fifo;
AVRational tb;
/* stream head: largest timestamp seen */
int64_t head_ts;
int limiting;
/* no more frames will be sent for this stream */
int finished;
uint64_t frames_sent;
uint64_t frames_max;
} SyncQueueStream;
struct SyncQueue {
enum SyncQueueType type;
/* no more frames will be sent for any stream */
int finished;
/* sync head: the stream with the _smallest_ head timestamp
* this stream determines which frames can be output */
int head_stream;
/* the finished stream with the smallest finish timestamp or -1 */
int head_finished_stream;
// maximum buffering duration in microseconds
int64_t buf_size_us;
SyncQueueStream *streams;
unsigned int nb_streams;
// pool of preallocated frames to avoid constant allocations
ObjPool *pool;
};
static void frame_move(const SyncQueue *sq, SyncQueueFrame dst,
SyncQueueFrame src)
{
if (sq->type == SYNC_QUEUE_PACKETS)
av_packet_move_ref(dst.p, src.p);
else
av_frame_move_ref(dst.f, src.f);
}
static int64_t frame_ts(const SyncQueue *sq, SyncQueueFrame frame)
{
return (sq->type == SYNC_QUEUE_PACKETS) ?
frame.p->pts + frame.p->duration :
frame.f->pts + frame.f->duration;
}
static int frame_null(const SyncQueue *sq, SyncQueueFrame frame)
{
return (sq->type == SYNC_QUEUE_PACKETS) ? (frame.p == NULL) : (frame.f == NULL);
}
static void finish_stream(SyncQueue *sq, unsigned int stream_idx)
{
SyncQueueStream *st = &sq->streams[stream_idx];
st->finished = 1;
if (st->limiting && st->head_ts != AV_NOPTS_VALUE) {
/* check if this stream is the new finished head */
if (sq->head_finished_stream < 0 ||
av_compare_ts(st->head_ts, st->tb,
sq->streams[sq->head_finished_stream].head_ts,
sq->streams[sq->head_finished_stream].tb) < 0) {
sq->head_finished_stream = stream_idx;
}
/* mark as finished all streams that should no longer receive new frames,
* due to them being ahead of some finished stream */
st = &sq->streams[sq->head_finished_stream];
for (unsigned int i = 0; i < sq->nb_streams; i++) {
SyncQueueStream *st1 = &sq->streams[i];
if (st != st1 && st1->head_ts != AV_NOPTS_VALUE &&
av_compare_ts(st->head_ts, st->tb, st1->head_ts, st1->tb) <= 0)
st1->finished = 1;
}
}
/* mark the whole queue as finished if all streams are finished */
for (unsigned int i = 0; i < sq->nb_streams; i++) {
if (!sq->streams[i].finished)
return;
}
sq->finished = 1;
}
static void queue_head_update(SyncQueue *sq)
{
if (sq->head_stream < 0) {
/* wait for one timestamp in each stream before determining
* the queue head */
for (unsigned int i = 0; i < sq->nb_streams; i++) {
SyncQueueStream *st = &sq->streams[i];
if (st->limiting && st->head_ts == AV_NOPTS_VALUE)
return;
}
// placeholder value, correct one will be found below
sq->head_stream = 0;
}
for (unsigned int i = 0; i < sq->nb_streams; i++) {
SyncQueueStream *st_head = &sq->streams[sq->head_stream];
SyncQueueStream *st_other = &sq->streams[i];
if (st_other->limiting && st_other->head_ts != AV_NOPTS_VALUE &&
av_compare_ts(st_other->head_ts, st_other->tb,
st_head->head_ts, st_head->tb) < 0)
sq->head_stream = i;
}
}
/* update this stream's head timestamp */
static void stream_update_ts(SyncQueue *sq, unsigned int stream_idx, int64_t ts)
{
SyncQueueStream *st = &sq->streams[stream_idx];
if (ts == AV_NOPTS_VALUE ||
(st->head_ts != AV_NOPTS_VALUE && st->head_ts >= ts))
return;
st->head_ts = ts;
/* if this stream is now ahead of some finished stream, then
* this stream is also finished */
if (sq->head_finished_stream >= 0 &&
av_compare_ts(sq->streams[sq->head_finished_stream].head_ts,
sq->streams[sq->head_finished_stream].tb,
ts, st->tb) <= 0)
finish_stream(sq, stream_idx);
/* update the overall head timestamp if it could have changed */
if (st->limiting &&
(sq->head_stream < 0 || sq->head_stream == stream_idx))
queue_head_update(sq);
}
/* If the queue for the given stream (or all streams when stream_idx=-1)
* is overflowing, trigger a fake heartbeat on lagging streams.
*
* @return 1 if heartbeat triggered, 0 otherwise
*/
static int overflow_heartbeat(SyncQueue *sq, int stream_idx)
{
SyncQueueStream *st;
SyncQueueFrame frame;
int64_t tail_ts = AV_NOPTS_VALUE;
/* if no stream specified, pick the one that is most ahead */
if (stream_idx < 0) {
int64_t ts = AV_NOPTS_VALUE;
for (int i = 0; i < sq->nb_streams; i++) {
st = &sq->streams[i];
if (st->head_ts != AV_NOPTS_VALUE &&
(ts == AV_NOPTS_VALUE ||
av_compare_ts(ts, sq->streams[stream_idx].tb,
st->head_ts, st->tb) < 0)) {
ts = st->head_ts;
stream_idx = i;
}
}
/* no stream has a timestamp yet -> nothing to do */
if (stream_idx < 0)
return 0;
}
st = &sq->streams[stream_idx];
/* get the chosen stream's tail timestamp */
for (size_t i = 0; tail_ts == AV_NOPTS_VALUE &&
av_fifo_peek(st->fifo, &frame, 1, i) >= 0; i++)
tail_ts = frame_ts(sq, frame);
/* overflow triggers when the tail is over specified duration behind the head */
if (tail_ts == AV_NOPTS_VALUE || tail_ts >= st->head_ts ||
av_rescale_q(st->head_ts - tail_ts, st->tb, AV_TIME_BASE_Q) < sq->buf_size_us)
return 0;
/* signal a fake timestamp for all streams that prevent tail_ts from being output */
tail_ts++;
for (unsigned int i = 0; i < sq->nb_streams; i++) {
SyncQueueStream *st1 = &sq->streams[i];
int64_t ts;
if (st == st1 || st1->finished ||
(st1->head_ts != AV_NOPTS_VALUE &&
av_compare_ts(tail_ts, st->tb, st1->head_ts, st1->tb) <= 0))
continue;
ts = av_rescale_q(tail_ts, st->tb, st1->tb);
if (st1->head_ts != AV_NOPTS_VALUE)
ts = FFMAX(st1->head_ts + 1, ts);
stream_update_ts(sq, i, ts);
}
return 1;
}
int sq_send(SyncQueue *sq, unsigned int stream_idx, SyncQueueFrame frame)
{
SyncQueueStream *st;
SyncQueueFrame dst;
int64_t ts;
int ret;
av_assert0(stream_idx < sq->nb_streams);
st = &sq->streams[stream_idx];
av_assert0(st->tb.num > 0 && st->tb.den > 0);
if (frame_null(sq, frame)) {
finish_stream(sq, stream_idx);
return 0;
}
if (st->finished)
return AVERROR_EOF;
ret = objpool_get(sq->pool, (void**)&dst);
if (ret < 0)
return ret;
frame_move(sq, dst, frame);
ts = frame_ts(sq, dst);
ret = av_fifo_write(st->fifo, &dst, 1);
if (ret < 0) {
frame_move(sq, frame, dst);
objpool_release(sq->pool, (void**)&dst);
return ret;
}
stream_update_ts(sq, stream_idx, ts);
st->frames_sent++;
if (st->frames_sent >= st->frames_max)
finish_stream(sq, stream_idx);
return 0;
}
static int receive_for_stream(SyncQueue *sq, unsigned int stream_idx,
SyncQueueFrame frame)
{
SyncQueueStream *st_head = sq->head_stream >= 0 ?
&sq->streams[sq->head_stream] : NULL;
SyncQueueStream *st;
av_assert0(stream_idx < sq->nb_streams);
st = &sq->streams[stream_idx];
if (av_fifo_can_read(st->fifo)) {
SyncQueueFrame peek;
int64_t ts;
int cmp = 1;
av_fifo_peek(st->fifo, &peek, 1, 0);
ts = frame_ts(sq, peek);
/* check if this stream's tail timestamp does not overtake
* the overall queue head */
if (ts != AV_NOPTS_VALUE && st_head)
cmp = av_compare_ts(ts, st->tb, st_head->head_ts, st_head->tb);
/* We can release frames that do not end after the queue head.
* Frames with no timestamps are just passed through with no conditions.
*/
if (cmp <= 0 || ts == AV_NOPTS_VALUE) {
frame_move(sq, frame, peek);
objpool_release(sq->pool, (void**)&peek);
av_fifo_drain2(st->fifo, 1);
return 0;
}
}
return (sq->finished || (st->finished && !av_fifo_can_read(st->fifo))) ?
AVERROR_EOF : AVERROR(EAGAIN);
}
static int receive_internal(SyncQueue *sq, int stream_idx, SyncQueueFrame frame)
{
int nb_eof = 0;
int ret;
/* read a frame for a specific stream */
if (stream_idx >= 0) {
ret = receive_for_stream(sq, stream_idx, frame);
return (ret < 0) ? ret : stream_idx;
}
/* read a frame for any stream with available output */
for (unsigned int i = 0; i < sq->nb_streams; i++) {
ret = receive_for_stream(sq, i, frame);
if (ret == AVERROR_EOF || ret == AVERROR(EAGAIN)) {
nb_eof += (ret == AVERROR_EOF);
continue;
}
return (ret < 0) ? ret : i;
}
return (nb_eof == sq->nb_streams) ? AVERROR_EOF : AVERROR(EAGAIN);
}
int sq_receive(SyncQueue *sq, int stream_idx, SyncQueueFrame frame)
{
int ret = receive_internal(sq, stream_idx, frame);
/* try again if the queue overflowed and triggered a fake heartbeat
* for lagging streams */
if (ret == AVERROR(EAGAIN) && overflow_heartbeat(sq, stream_idx))
ret = receive_internal(sq, stream_idx, frame);
return ret;
}
int sq_add_stream(SyncQueue *sq, int limiting)
{
SyncQueueStream *tmp, *st;
tmp = av_realloc_array(sq->streams, sq->nb_streams + 1, sizeof(*sq->streams));
if (!tmp)
return AVERROR(ENOMEM);
sq->streams = tmp;
st = &sq->streams[sq->nb_streams];
memset(st, 0, sizeof(*st));
st->fifo = av_fifo_alloc2(1, sizeof(SyncQueueFrame), AV_FIFO_FLAG_AUTO_GROW);
if (!st->fifo)
return AVERROR(ENOMEM);
/* we set a valid default, so that a pathological stream that never
* receives even a real timebase (and no frames) won't stall all other
* streams forever; cf. overflow_heartbeat() */
st->tb = (AVRational){ 1, 1 };
st->head_ts = AV_NOPTS_VALUE;
st->frames_max = UINT64_MAX;
st->limiting = limiting;
return sq->nb_streams++;
}
void sq_set_tb(SyncQueue *sq, unsigned int stream_idx, AVRational tb)
{
SyncQueueStream *st;
av_assert0(stream_idx < sq->nb_streams);
st = &sq->streams[stream_idx];
av_assert0(!av_fifo_can_read(st->fifo));
if (st->head_ts != AV_NOPTS_VALUE)
st->head_ts = av_rescale_q(st->head_ts, st->tb, tb);
st->tb = tb;
}
void sq_limit_frames(SyncQueue *sq, unsigned int stream_idx, uint64_t frames)
{
SyncQueueStream *st;
av_assert0(stream_idx < sq->nb_streams);
st = &sq->streams[stream_idx];
st->frames_max = frames;
if (st->frames_sent >= st->frames_max)
finish_stream(sq, stream_idx);
}
SyncQueue *sq_alloc(enum SyncQueueType type, int64_t buf_size_us)
{
SyncQueue *sq = av_mallocz(sizeof(*sq));
if (!sq)
return NULL;
sq->type = type;
sq->buf_size_us = buf_size_us;
sq->head_stream = -1;
sq->head_finished_stream = -1;
sq->pool = (type == SYNC_QUEUE_PACKETS) ? objpool_alloc_packets() :
objpool_alloc_frames();
if (!sq->pool) {
av_freep(&sq);
return NULL;
}
return sq;
}
void sq_free(SyncQueue **psq)
{
SyncQueue *sq = *psq;
if (!sq)
return;
for (unsigned int i = 0; i < sq->nb_streams; i++) {
SyncQueueFrame frame;
while (av_fifo_read(sq->streams[i].fifo, &frame, 1) >= 0)
objpool_release(sq->pool, (void**)&frame);
av_fifo_freep2(&sq->streams[i].fifo);
}
av_freep(&sq->streams);
objpool_free(&sq->pool);
av_freep(psq);
}
nb_streams
__thread int nb_streams
Definition fftools_ffprobe.c:336
objpool_alloc_packets
ObjPool * objpool_alloc_packets(void)
Definition fftools_objpool.c:138
objpool_alloc_frames
ObjPool * objpool_alloc_frames(void)
Definition fftools_objpool.c:142
objpool_release
void objpool_release(ObjPool *op, void **obj)
Definition fftools_objpool.c:92
objpool_free
void objpool_free(ObjPool **pop)
Definition fftools_objpool.c:68
objpool_get
int objpool_get(ObjPool *op, void **obj)
Definition fftools_objpool.c:81
fftools_objpool.h
frame_ts
static int64_t frame_ts(const SyncQueue *sq, SyncQueueFrame frame)
Definition fftools_sync_queue.c:89
sq_alloc
SyncQueue * sq_alloc(enum SyncQueueType type, int64_t buf_size_us)
Definition fftools_sync_queue.c:419
queue_head_update
static void queue_head_update(SyncQueue *sq)
Definition fftools_sync_queue.c:135
finish_stream
static void finish_stream(SyncQueue *sq, unsigned int stream_idx)
Definition fftools_sync_queue.c:101
sq_send
int sq_send(SyncQueue *sq, unsigned int stream_idx, SyncQueueFrame frame)
Definition fftools_sync_queue.c:248
receive_for_stream
static int receive_for_stream(SyncQueue *sq, unsigned int stream_idx, SyncQueueFrame frame)
Definition fftools_sync_queue.c:291
sq_set_tb
void sq_set_tb(SyncQueue *sq, unsigned int stream_idx, AVRational tb)
Definition fftools_sync_queue.c:392
stream_update_ts
static void stream_update_ts(SyncQueue *sq, unsigned int stream_idx, int64_t ts)
Definition fftools_sync_queue.c:161
frame_null
static int frame_null(const SyncQueue *sq, SyncQueueFrame frame)
Definition fftools_sync_queue.c:96
sq_limit_frames
void sq_limit_frames(SyncQueue *sq, unsigned int stream_idx, uint64_t frames)
Definition fftools_sync_queue.c:407
sq_receive
int sq_receive(SyncQueue *sq, int stream_idx, SyncQueueFrame frame)
Definition fftools_sync_queue.c:353
overflow_heartbeat
static int overflow_heartbeat(SyncQueue *sq, int stream_idx)
Definition fftools_sync_queue.c:190
frame_move
static void frame_move(const SyncQueue *sq, SyncQueueFrame dst, SyncQueueFrame src)
Definition fftools_sync_queue.c:80
receive_internal
static int receive_internal(SyncQueue *sq, int stream_idx, SyncQueueFrame frame)
Definition fftools_sync_queue.c:329
sq_free
void sq_free(SyncQueue **psq)
Definition fftools_sync_queue.c:442
sq_add_stream
int sq_add_stream(SyncQueue *sq, int limiting)
Definition fftools_sync_queue.c:365
fftools_sync_queue.h
SyncQueueType
SyncQueueType
Definition fftools_sync_queue.h:41
SYNC_QUEUE_PACKETS
@ SYNC_QUEUE_PACKETS
Definition fftools_sync_queue.h:42
ObjPool
Definition fftools_objpool.c:44
SyncQueue
Definition fftools_sync_queue.c:59
SyncQueue::finished
int finished
Definition fftools_sync_queue.c:63
SyncQueue::streams
SyncQueueStream * streams
Definition fftools_sync_queue.c:73
SyncQueue::head_stream
int head_stream
Definition fftools_sync_queue.c:66
SyncQueue::type
enum SyncQueueType type
Definition fftools_sync_queue.c:60
SyncQueue::pool
ObjPool * pool
Definition fftools_sync_queue.c:77
SyncQueue::buf_size_us
int64_t buf_size_us
Definition fftools_sync_queue.c:71
SyncQueue::nb_streams
unsigned int nb_streams
Definition fftools_sync_queue.c:74
SyncQueue::head_finished_stream
int head_finished_stream
Definition fftools_sync_queue.c:68
SyncQueueStream
Definition fftools_sync_queue.c:45
SyncQueueStream::tb
AVRational tb
Definition fftools_sync_queue.c:47
SyncQueueStream::limiting
int limiting
Definition fftools_sync_queue.c:51
SyncQueueStream::finished
int finished
Definition fftools_sync_queue.c:53
SyncQueueStream::fifo
AVFifo * fifo
Definition fftools_sync_queue.c:46
SyncQueueStream::frames_sent
uint64_t frames_sent
Definition fftools_sync_queue.c:55
SyncQueueStream::frames_max
uint64_t frames_max
Definition fftools_sync_queue.c:56
SyncQueueStream::head_ts
int64_t head_ts
Definition fftools_sync_queue.c:50
SyncQueueFrame
Definition fftools_sync_queue.h:46
SyncQueueFrame::f
AVFrame * f
Definition fftools_sync_queue.h:47
SyncQueueFrame::p
AVPacket * p
Definition fftools_sync_queue.h:48