‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Thursday, 18 de April de 2019 11:01, Andreas Håkon via ffmpeg-devel
<ffmpeg-devel@ffmpeg.org> wrote:
> Hi,
>
> This patch resolves one very specific use case:
>
> - When you use the mpegts muxer;
> - And use the global parameter “-copyts”;
> - And use the parameter “-muxrate” for the mpegts muxer;
> - And use too the parameter “-mpegts_copyts”.
>
> The problem is created because the member “first_pcr” of the MpegTSWrite
> struct isn’t initialized with a correct timestamp (so when copying the
> timestamps the initial value is 0). And in this case an infinite loop is
> created because the code never writes PES packets when the “mux_rate” isn’t
> VBR (equals to 1). See the block that creates the loop here (note the
> "continue" command at end):
>
> https://github.com/FFmpeg/FFmpeg/blob/a0559fcd81f42f446c93357a943699f9d44eeb79/libavformat/mpegtsenc.c#L1211
>
> So, this patch fixes the problem initializing the “first_pcr” with the
> first DTS value that comes when using the incoming timestamps.
>
> Regards.
> A.H.
>
Hi,
Here a new version of the patch.
The "fist_pcr" value is now derived from DTS in a more consistent way.
Regards,
A.H.
---
From c59569ca9426fef455edabfa648cb2ff678c1640 Mon Sep 17 00:00:00 2001
From: Andreas Hakon <andreas.ha...@protonmail.com>
Date: Fri, 19 Apr 2019 09:32:33 +0100
Subject: [PATCH] libavformat: fix copyts and muxrate in mpegts muxer v2
When using "-copyts" and "-muxrate" with the mpegts muxer the muxing fails
because the member "first_pcr" of the MpegTSWrite struct isn't initialized
with a correct timestamp.
The behaviour of the error is an infinite loop created in the function
mpegts_write_pes() because the code never writes PES packets.
This patch resolves the problem initializing the "first_pcr" with a value
derived from the first DTS value seen.
Signed-off-by: Andreas Hakon <andreas.ha...@protonmail.com>
---
libavformat/mpegtsenc.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
index fc0ea22..858b0d7 100644
--- a/libavformat/mpegtsenc.c
+++ b/libavformat/mpegtsenc.c
@@ -971,6 +971,9 @@ static int mpegts_init(AVFormatContext *s)
if (ts->copyts < 1)
ts->first_pcr = av_rescale(s->max_delay, PCR_TIME_BASE,
AV_TIME_BASE);
+ else
+ ts->first_pcr = AV_NOPTS_VALUE;
+
} else {
/* Arbitrary values, PAT/PMT will also be written on video key frames
*/
ts->sdt_packet_period = 200;
@@ -1186,12 +1189,16 @@ static void mpegts_write_pes(AVFormatContext *s,
AVStream *st,
int64_t pcr = -1; /* avoid warning */
int64_t delay = av_rescale(s->max_delay, 90000, AV_TIME_BASE);
int force_pat = st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && key &&
!ts_st->prev_payload_key;
+ int last_payload_size = 0;
av_assert0(ts_st->payload != buf || st->codecpar->codec_type !=
AVMEDIA_TYPE_VIDEO);
if (ts->flags & MPEGTS_FLAG_PAT_PMT_AT_FRAMES && st->codecpar->codec_type
== AVMEDIA_TYPE_VIDEO) {
force_pat = 1;
}
+ if (ts->mux_rate > 1 && dts != AV_NOPTS_VALUE && ts->first_pcr ==
AV_NOPTS_VALUE)
+ ts->first_pcr = (dts * 300) - av_rescale(s->max_delay, PCR_TIME_BASE,
AV_TIME_BASE);
+
is_start = 1;
while (payload_size > 0) {
retransmit_si_info(s, force_pat, dts);
@@ -1209,12 +1216,13 @@ static void mpegts_write_pes(AVFormatContext *s,
AVStream *st,
}
if (ts->mux_rate > 1 && dts != AV_NOPTS_VALUE &&
- (dts - get_pcr(ts, s->pb) / 300) > delay) {
+ last_payload_size != payload_size && (dts - get_pcr(ts, s->pb) /
300) > delay) {
/* pcr insert gets priority over null packet insert */
if (write_pcr)
mpegts_insert_pcr_only(s, st);
else
mpegts_insert_null_packet(s);
+ last_payload_size = payload_size;
/* recalculate write_pcr and possibly retransmit si_info */
continue;
}
--
1.7.10.4
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