Hi,
A patch for a new optional parameter for the mpegtsenc muxer.
Regards.
A.H.
---
From 7f9f1a992615e15121b661d4cd1b9c1e32e1c894 Mon Sep 17 00:00:00 2001
From: Andreas Hakon <andreas.ha...@protonmail.com>
Date: Thu, 25 Apr 2019 09:49:29 +0100
Subject: [PATCH] libavformat/mpegtsenc: enforce PCR packets without payload
This patch provides a new optional parameter for the mpegtsenc muxer.
The parameter "-pcr_without_payload" can be used to override the default
behaviour of writing PCR timestamps in TS packets with payload.
Using a value greater than 0 all TS packets carrying PCR timestamps will
be forced to have an empty payload. Otherwise (with 0) the regular behaviour is
used and PCR packets can have payload. Futhermore with a value greater than 1
the packet with the PCR will be repeated the number of times indicated.
The default value is "-pcr_without_payload 0", which corresponds to the current
behaviour.
This can be handy for many reasons.
Signed-off-by: Andreas Hakon <andreas.ha...@protonmail.com>
---
doc/muxers.texi | 5 +++++
libavformat/mpegtsenc.c | 18 ++++++++++++++----
2 files changed, 19 insertions(+), 4 deletions(-)
diff --git a/doc/muxers.texi b/doc/muxers.texi
index 83ae017..9acdee3 100644
--- a/doc/muxers.texi
+++ b/doc/muxers.texi
@@ -1564,6 +1564,11 @@ Set a constant muxrate. Default is VBR.
@item pes_payload_size @var{integer}
Set minimum PES packet payload in bytes. Default is @code{2930}.
+@item pcr_without_payload @var{integer}
+Generates PCR packets without payload. When the value is greater than 1
+it repeats the PCR packet N times. With a 0 value it generates regular
+PCR packets with payload. Default is @code{0}.
+
@item mpegts_flags @var{flags}
Set mpegts flags. Accepts the following options:
@table @samp
diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
index fc0ea22..0cc42cd 100644
--- a/libavformat/mpegtsenc.c
+++ b/libavformat/mpegtsenc.c
@@ -97,6 +97,7 @@ typedef struct MpegTSWrite {
int pmt_start_pid;
int start_pid;
int m2ts_mode;
+ int pcr_repetition;
int reemit_pat_pmt; // backward compatibility
@@ -1093,12 +1094,13 @@ static void mpegts_insert_null_packet(AVFormatContext
*s)
}
/* Write a single transport stream packet with a PCR and no payload */
-static void mpegts_insert_pcr_only(AVFormatContext *s, AVStream *st)
+static void mpegts_insert_pcr_only(AVFormatContext *s, AVStream *st, int
repetition)
{
MpegTSWrite *ts = s->priv_data;
MpegTSWriteStream *ts_st = st->priv_data;
uint8_t *q;
uint8_t buf[TS_PACKET_SIZE];
+ int i;
q = buf;
*q++ = 0x47;
@@ -1119,7 +1121,9 @@ static void mpegts_insert_pcr_only(AVFormatContext *s,
AVStream *st)
/* stuffing bytes */
memset(q, 0xFF, TS_PACKET_SIZE - (q - buf));
mpegts_prefix_m2ts_header(s);
- avio_write(s->pb, buf, TS_PACKET_SIZE);
+ for (i=0; i<repetition; i++) {
+ avio_write(s->pb, buf, TS_PACKET_SIZE);
+ }
}
static void write_pts(uint8_t *q, int fourbits, int64_t pts)
@@ -1212,12 +1216,15 @@ static void mpegts_write_pes(AVFormatContext *s,
AVStream *st,
(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);
+ mpegts_insert_pcr_only(s, st, ts->pcr_repetition < 1 ? 1 :
ts->pcr_repetition);
else
mpegts_insert_null_packet(s);
/* recalculate write_pcr and possibly retransmit si_info */
continue;
}
+ if (write_pcr && ts->pcr_repetition > 0) {
+ mpegts_insert_pcr_only(s, st, ts->pcr_repetition);
+ }
/* prepare packet header */
q = buf;
@@ -1241,7 +1248,7 @@ static void mpegts_write_pes(AVFormatContext *s, AVStream
*st,
set_af_flag(buf, 0x40);
q = get_ts_payload_start(buf);
}
- if (write_pcr) {
+ if (write_pcr && ts->pcr_repetition == 0) {
set_af_flag(buf, 0x10);
q = get_ts_payload_start(buf);
// add 11, pcr references the last byte of program clock reference
base
@@ -1926,6 +1933,9 @@ static const AVOption options[] = {
{ "pes_payload_size", "Minimum PES packet payload in bytes",
offsetof(MpegTSWrite, pes_payload_size), AV_OPT_TYPE_INT,
{ .i64 = DEFAULT_PES_PAYLOAD_SIZE }, 0, INT_MAX,
AV_OPT_FLAG_ENCODING_PARAM },
+ { "pcr_without_payload", "Generate PCR packets without payload",
+ offsetof(MpegTSWrite, pcr_repetition), AV_OPT_TYPE_INT,
+ { .i64 = 0 }, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
{ "mpegts_flags", "MPEG-TS muxing flags",
offsetof(MpegTSWrite, flags), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, 0,
INT_MAX,
AV_OPT_FLAG_ENCODING_PARAM, "mpegts_flags" },
--
1.7.10.4
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