[FFmpeg-devel] libavformat/mpegtsenc: fix incorrect PCR with multiple programs [v3]
Marton Balint
cus at passwd.hu
Thu Aug 1 00:58:58 EEST 2019
On Sun, 28 Jul 2019, Andreas Håkon wrote:
> Hi,
>
> This last version fixes the small bug discovered by Michael Niedermayer:
> https://patchwork.ffmpeg.org/patch/14099/
>
> This version is finally clean.
> From 8381febd0e881cfcd53583b0ccdd7eb2c580e422 Mon Sep 17 00:00:00 2001
> From: Andreas Hakon <andreas.hakon at protonmail.com>
> Date: Mon, 29 Jul 2019 12:02:06 +0100
> Subject: [PATCH] libavformat/mpegtsenc: fix incorrect PCR with multiple
> programs [v4]
>
> The MPEG-TS muxer has a serious bug related to the use of multiple programs:
> in that case, the PCR pid selection is incomplete for all services except one.
> This patch solves this problem and select correct streams for each program.
> Furthermore, it passes all the checks and doesn't generate any regression.
> Also fully compatible with shared pids over services.
>
> You can check it with this example command:
>
> $ ./ffmpeg -loglevel verbose -y -f data -i /dev/zero \
> -filter_complex "nullsrc=s=60x60,split=2[v0][v1],anullsrc[a]" \
> -map [v0] -c:v:0 rawvideo \
> -map [v1] -c:v:1 rawvideo \
> -map [a] -c:a:0 pcm_s8 \
> -program st=0,2 -program st=1,2 -program st=2 -program st=0 -f mpegts out.ts
>
> And you will see something like:
>
> [mpegts @ 0x55f8452797c0] service 1 using PCR in pid=256
> [mpegts @ 0x55f8452797c0] service 2 using PCR in pid=257
> [mpegts @ 0x55f8452797c0] service 3 using PCR in pid=258
> [mpegts @ 0x55f8452797c0] service 4 using PCR in pid=256
>
>
> Signed-off-by: Andreas Hakon <andreas.hakon at protonmail.com>
> ---
> libavformat/mpegtsenc.c | 167 +++++++++++++++++++++++++++++------------------
> 1 file changed, 105 insertions(+), 62 deletions(-)
>
> diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
> index fc0ea22..6a0dd55 100644
> --- a/libavformat/mpegtsenc.c
> +++ b/libavformat/mpegtsenc.c
> @@ -60,6 +60,7 @@ typedef struct MpegTSService {
> int pcr_packet_count;
> int pcr_packet_period;
> AVProgram *program;
> + AVStream *pcr_st;
> } MpegTSService;
>
> // service_type values as defined in ETSI 300 468
> @@ -774,7 +775,7 @@ static int mpegts_init(AVFormatContext *s)
> MpegTSWrite *ts = s->priv_data;
> MpegTSWriteStream *ts_st;
> MpegTSService *service;
> - AVStream *st, *pcr_st = NULL;
> + AVStream *st;
> AVDictionaryEntry *title, *provider;
> int i, j;
> const char *service_name;
> @@ -831,6 +832,11 @@ static int mpegts_init(AVFormatContext *s)
> }
> }
>
> + for (i = 0; i < ts->nb_services; i++) {
> + service = ts->services[i];
> + service->pcr_st = NULL;
> + }
> +
This loop is not needed as far as I see. service is already initialized
and service->pcr_st is zero initialized so you don't need to set it to
NULL explicitly.
> ts->pat.pid = PAT_PID;
> /* Initialize at 15 so that it wraps and is equal to 0 for the
> * first packet we write. */
> @@ -872,17 +878,6 @@ static int mpegts_init(AVFormatContext *s)
> goto fail;
> }
>
> - program = av_find_program_from_stream(s, NULL, i);
> - if (program) {
> - for (j = 0; j < ts->nb_services; j++) {
> - if (ts->services[j]->program == program) {
> - service = ts->services[j];
> - break;
> - }
> - }
> - }
> -
> - ts_st->service = service;
> /* MPEG pid values < 16 are reserved. Applications which set st->id in
> * this range are assigned a calculated pid. */
> if (st->id < 16) {
> @@ -895,11 +890,6 @@ static int mpegts_init(AVFormatContext *s)
> ret = AVERROR(EINVAL);
> goto fail;
> }
> - if (ts_st->pid == service->pmt.pid) {
> - av_log(s, AV_LOG_ERROR, "Duplicate stream id %d\n", ts_st->pid);
> - ret = AVERROR(EINVAL);
> - goto fail;
> - }
> for (j = 0; j < i; j++) {
> if (pids[j] == ts_st->pid) {
> av_log(s, AV_LOG_ERROR, "Duplicate stream id %d\n", ts_st->pid);
> @@ -913,12 +903,7 @@ static int mpegts_init(AVFormatContext *s)
> ts_st->first_pts_check = 1;
> ts_st->cc = 15;
> ts_st->discontinuity = ts->flags & MPEGTS_FLAG_DISCONT;
> - /* update PCR pid by using the first video stream */
> - if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
> - service->pcr_pid == 0x1fff) {
> - service->pcr_pid = ts_st->pid;
> - pcr_st = st;
> - }
> +
> if (st->codecpar->codec_id == AV_CODEC_ID_AAC &&
> st->codecpar->extradata_size > 0) {
> AVStream *ast;
> @@ -949,50 +934,109 @@ static int mpegts_init(AVFormatContext *s)
> if (st->codecpar->codec_id == AV_CODEC_ID_OPUS) {
> ts_st->opus_pending_trim_start = st->codecpar->initial_padding * 48000 / st->codecpar->sample_rate;
> }
> +
> + /* program service checks */
> + program = av_find_program_from_stream(s, NULL, i);
> + do {
> + for (j = 0; j < ts->nb_services; j++) {
> + if (program) {
> + /* search for the services corresponding to this program */
> + if (ts->services[j]->program == program)
> + service = ts->services[j];
> + else
> + continue;
> + }
Maybe I miss something but as far as I see only this block needs to be in
the loop, the rest is not. So you can actually write this:
/* program service checks */
program = av_find_program_from_stream(s, NULL, i);
do {
if (program) {
for (j = 0; j < ts->nb_services; j++) {
if (ts->services[j]->program == program) {
service = ts->services[j];
break;
}
}
}
ts_st->service = service;
/* check for PMT pid conflicts */
...
This way you also ensure that ts_st->service is always set for every
stream which is kind of how the old code worked, right?
> +
> + ts_st->service = service;
You are setting this for all programs of the stream, so effectively the
stream's service will be the last program (service) the stream is part of.
Maybe you should aim for the first instead?
> +
> + /* check for PMT pid conflicts */
> + if (ts_st->pid == service->pmt.pid) {
> + av_log(s, AV_LOG_ERROR, "Duplicate stream id %d\n", ts_st->pid);
> + ret = AVERROR(EINVAL);
> + goto fail;
> + }
> +
> + /* update PCR pid by using the first video stream */
> + if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
> + service->pcr_pid == 0x1fff) {
> + service->pcr_pid = ts_st->pid;
> + service->pcr_st = st;
> + }
> +
> + /* store this stream as a candidate PCR if the service doesn't have any */
> + if (service->pcr_pid == 0x1fff &&
> + !service->pcr_st) {
> + service->pcr_st = st;
> + }
> +
> + /* exit when just one single service */
> + if (!program)
> + break;
With the change above this check should be no longer needed.
> + }
> + program = program ? av_find_program_from_stream(s, program, i) : NULL;
> + } while (program);
> }
>
> av_freep(&pids);
>
> - /* if no video stream, use the first stream as PCR */
> - if (service->pcr_pid == 0x1fff && s->nb_streams > 0) {
> - pcr_st = s->streams[0];
> - ts_st = pcr_st->priv_data;
> - service->pcr_pid = ts_st->pid;
> - } else
> - ts_st = pcr_st->priv_data;
> -
> - if (ts->mux_rate > 1) {
> - service->pcr_packet_period = (int64_t)ts->mux_rate * ts->pcr_period /
> - (TS_PACKET_SIZE * 8 * 1000);
> - ts->sdt_packet_period = (int64_t)ts->mux_rate * SDT_RETRANS_TIME /
> - (TS_PACKET_SIZE * 8 * 1000);
> - ts->pat_packet_period = (int64_t)ts->mux_rate * PAT_RETRANS_TIME /
> - (TS_PACKET_SIZE * 8 * 1000);
> -
> - if (ts->copyts < 1)
> - ts->first_pcr = av_rescale(s->max_delay, PCR_TIME_BASE, AV_TIME_BASE);
> - } else {
> - /* Arbitrary values, PAT/PMT will also be written on video key frames */
> - ts->sdt_packet_period = 200;
> - ts->pat_packet_period = 40;
> - if (pcr_st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
> - int frame_size = av_get_audio_frame_duration2(pcr_st->codecpar, 0);
> - if (!frame_size) {
> - av_log(s, AV_LOG_WARNING, "frame size not set\n");
> - service->pcr_packet_period =
> - pcr_st->codecpar->sample_rate / (10 * 512);
> + for (i = 0; i < ts->nb_services; i++) {
> + service = ts->services[i];
> +
> + if (!service->pcr_st) {
> + av_log(s, AV_LOG_ERROR, "no PCR selected for the service %i\n", service->sid);
> + ret = AVERROR(EINVAL);
> + goto fail_at_end;
> + }
> + /* get the PCR stream (real or candidate) */
> + ts_st = service->pcr_st->priv_data;
> +
> + /* if no video stream then use the pid of the candidate PCR */
> + if (service->pcr_pid == 0x1fff)
> + service->pcr_pid = ts_st->pid;
> +
> + if (ts->mux_rate > 1) {
> + service->pcr_packet_period = (int64_t)ts->mux_rate * ts->pcr_period /
> + (TS_PACKET_SIZE * 8 * 1000);
> + ts->sdt_packet_period = (int64_t)ts->mux_rate * SDT_RETRANS_TIME /
> + (TS_PACKET_SIZE * 8 * 1000);
> + ts->pat_packet_period = (int64_t)ts->mux_rate * PAT_RETRANS_TIME /
> + (TS_PACKET_SIZE * 8 * 1000);
> + if (ts->copyts < 1)
> + ts->first_pcr = av_rescale(s->max_delay, PCR_TIME_BASE, AV_TIME_BASE);
> + } else {
> + /* Arbitrary values, PAT/PMT will also be written on video key frames */
> + ts->sdt_packet_period = 200;
> + ts->pat_packet_period = 40;
> + if (service->pcr_st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
> + int frame_size = av_get_audio_frame_duration2(service->pcr_st->codecpar, 0);
> + if (!frame_size) {
> + av_log(s, AV_LOG_WARNING, "frame size not set\n");
> + service->pcr_packet_period =
> + service->pcr_st->codecpar->sample_rate / (10 * 512);
> + } else {
> + service->pcr_packet_period =
> + service->pcr_st->codecpar->sample_rate / (10 * frame_size);
> + }
> } else {
> + // max delta PCR 0.1s
> + // TODO: should be avg_frame_rate
> service->pcr_packet_period =
> - pcr_st->codecpar->sample_rate / (10 * frame_size);
> + ts_st->user_tb.den / (10 * ts_st->user_tb.num);
> }
> - } else {
> - // max delta PCR 0.1s
> - // TODO: should be avg_frame_rate
> - service->pcr_packet_period =
> - ts_st->user_tb.den / (10 * ts_st->user_tb.num);
> + if (!service->pcr_packet_period)
> + service->pcr_packet_period = 1;
> }
> - if (!service->pcr_packet_period)
> - service->pcr_packet_period = 1;
> +
> + // output a PCR as soon as possible
> + service->pcr_packet_count = service->pcr_packet_period;
> +
> + av_log(s, AV_LOG_VERBOSE, "service %i using PCR in pid=%i\n", service->sid, service->pcr_pid);
> + }
> +
> + if (!ts_st->service) {
> + av_log(s, AV_LOG_ERROR, "empty services!\n");
> + ret = AVERROR(EINVAL);
> + goto fail_at_end;
> }
I guess this check will no longer be needed if ts_st->service is always
set.
>
> ts->last_pat_ts = AV_NOPTS_VALUE;
> @@ -1005,8 +1049,6 @@ static int mpegts_init(AVFormatContext *s)
> ts->sdt_packet_period = INT_MAX;
> }
>
> - // output a PCR as soon as possible
> - service->pcr_packet_count = service->pcr_packet_period;
> ts->pat_packet_count = ts->pat_packet_period - 1;
> ts->sdt_packet_count = ts->sdt_packet_period - 1;
>
> @@ -1016,7 +1058,7 @@ static int mpegts_init(AVFormatContext *s)
> av_log(s, AV_LOG_VERBOSE, "muxrate %d, ", ts->mux_rate);
> av_log(s, AV_LOG_VERBOSE,
> "pcr every %d pkts, sdt every %d, pat/pmt every %d pkts\n",
> - service->pcr_packet_period,
> + ts_st->service->pcr_packet_period,
> ts->sdt_packet_period, ts->pat_packet_period);
>
> if (ts->m2ts_mode == -1) {
> @@ -1031,6 +1073,7 @@ static int mpegts_init(AVFormatContext *s)
>
> fail:
> av_freep(&pids);
> +fail_at_end:
> return ret;
> }
>
Regards,
Marton
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