Re: [FFmpeg-devel] [PATCH v3 3/3] avformat/mpegtsenc: Write stream_id into PES after stream_id decision
On Sat, Apr 24, 2021 at 5:09 PM Mao Hata wrote: > > > v3 patch looks good to me. > Then, since the patch itself is based on ISO_IEC_13818-1, it perhaps has > some (side) effects for ATSC/DVB as well. If possible, you might want to > wait for opinions from ATSC/DVB sides. > > Mao Hata > I will add arib_superimpose codec later once this patchset got merged. Just waiting for other maintainers to review and merge this, yet. Regards, zheng > P.S. > I confirmed the effect of your patch with the following command. > $ ffmpeg -i some_arib_mpeg.ts -c:v libx264 -map 0:v -c:a aac -map 0:a > -map 0:4 dest.ts > > Here "-map 0:4" points to private_stream_2 (ARIB-superimpose). > The command now properly remuxes "-map 0:4" stream into "dest.ts" > without any editing. > ___ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH v3 3/3] avformat/mpegtsenc: Write stream_id into PES after stream_id decision
On 2021/04/22 21:03, zheng qian wrote:
Changes since v2:
Fix PES_packet_length mismatch bug
According to the PES packet definition defined in Table 2-17
of ISO_IEC_13818-1 specification, some fields like PTS/DTS or
pes_extension could only appears if the stream_id meets the
condition:
if (stream_id != 0xBC && // program_stream_map
stream_id != 0xBE && // padding_stream
stream_id != 0xBF && // private_stream_2
stream_id != 0xF0 && // ECM
stream_id != 0xF1 && // EMM
stream_id != 0xFF && // program_stream_directory
stream_id != 0xF2 && // DSMCC_stream
stream_id != 0xF8) // ITU-T Rec. H.222.1 type E stream
And the following stream_id types don't have fields like PTS/DTS:
else if ( stream_id == program_stream_map
|| stream_id == private_stream_2
|| stream_id == ECM
|| stream_id == EMM
|| stream_id == program_stream_directory
|| stream_id == DSMCC_stream
|| stream_id == ITU-T Rec. H.222.1 type E stream ) {
for (i = 0; i < PES_packet_length; i++) {
PES_packet_data_byte
}
}
Current implementation skipped the judgement of stream_id
causing some kind of stream like private_stream_2 to be
incorrectly written with PTS/DTS field. For example,
Japan DTV transmits news and alerts through ARIB superimpose
that utilizes private_stream_2 still could not be remuxed
correctly for now.
This patch set fixes the remuxing for private_stream_2 and
other stream_id types.
Signed-off-by: zheng qian
---
libavformat/mpegtsenc.c | 15 +++
1 file changed, 15 insertions(+)
diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
index f302af84ff..b59dab5174 100644
--- a/libavformat/mpegtsenc.c
+++ b/libavformat/mpegtsenc.c
@@ -1476,6 +1476,16 @@ static void mpegts_write_pes(AVFormatContext *s,
AVStream *st,
}
}
header_len = 0;
+
+if (stream_id != 0xBC && // program_stream_map
+stream_id != 0xBE && // padding_stream
+stream_id != 0xBF && // private_stream_2
+stream_id != 0xF0 && // ECM
+stream_id != 0xF1 && // EMM
+stream_id != 0xFF && // program_stream_directory
+stream_id != 0xF2 && // DSMCC_stream
+stream_id != 0xF8) { // ITU-T Rec. H.222.1 type E stream > +
flags = 0;
if (pts != AV_NOPTS_VALUE) {
header_len += 5;
@@ -1569,6 +1579,11 @@ static void mpegts_write_pes(AVFormatContext *s,
AVStream *st,
memset(q, 0xff, pes_header_stuffing_bytes);
q += pes_header_stuffing_bytes;
}
+} else {
+len = payload_size;
+*q++ = len >> 8;
+*q++ = len;
+}
is_start = 0;
}
/* header size */
Your patch changes the behavior of mpegts_write_pes() function only if
its "st->codecpar->codec_type" parameter is AVMEDIA_TYPE_DATA. In other
cases, "stream_id" variable in this function is set to any of the following:
STREAM_ID_EXTENDED_STREAM_ID (0xfd)
STREAM_ID_VIDEO_STREAM_0 (0xe0)
STREAM_ID_AUDIO_STREAM_0 (0xc0)
STREAM_ID_EXTENDED_STREAM_ID (0xfd)
STREAM_ID_PRIVATE_STREAM_1 (0xbd)
So, the "if (stream_id != ...)" statement added by the patch is always
true, therefore, the function behaves the same as before.
If "st->codecpar->codec_type" parameter is AVMEDIA_TYPE_DATA, unless
additionally conditioned by "st->codecpar->codec_id" parameter,
basically, the "stream_id" value given as an argument is written to PES
packets as it is. In this case, the behavior of the function should be
fixed as you commented.
v3 patch looks good to me.
Then, since the patch itself is based on ISO_IEC_13818-1, it perhaps has
some (side) effects for ATSC/DVB as well. If possible, you might want to
wait for opinions from ATSC/DVB sides.
Mao Hata
P.S.
I confirmed the effect of your patch with the following command.
$ ffmpeg -i some_arib_mpeg.ts -c:v libx264 -map 0:v -c:a aac -map 0:a
-map 0:4 dest.ts
Here "-map 0:4" points to private_stream_2 (ARIB-superimpose).
The command now properly remuxes "-map 0:4" stream into "dest.ts"
without any editing.
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[FFmpeg-devel] [PATCH v3 3/3] avformat/mpegtsenc: Write stream_id into PES after stream_id decision
Since stream_id will have effect on the existences of
PES header fields like PTS/DTS, it should be better to
guarantee stream_id variable to be identical with
exact written value.
Signed-off-by: zheng qian
---
libavformat/mpegtsenc.c | 15 ---
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
index 967f98931d..525c68ffd1 100644
--- a/libavformat/mpegtsenc.c
+++ b/libavformat/mpegtsenc.c
@@ -1445,28 +1445,28 @@ static void mpegts_write_pes(AVFormatContext *s,
AVStream *st,
is_dvb_teletext = 0;
if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
if (st->codecpar->codec_id == AV_CODEC_ID_DIRAC)
-*q++ = STREAM_ID_EXTENDED_STREAM_ID;
+stream_id = STREAM_ID_EXTENDED_STREAM_ID;
else
-*q++ = STREAM_ID_VIDEO_STREAM_0;
+stream_id = STREAM_ID_VIDEO_STREAM_0;
} else if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
(st->codecpar->codec_id == AV_CODEC_ID_MP2 ||
st->codecpar->codec_id == AV_CODEC_ID_MP3 ||
st->codecpar->codec_id == AV_CODEC_ID_AAC)) {
-*q++ = STREAM_ID_AUDIO_STREAM_0;
+stream_id = STREAM_ID_AUDIO_STREAM_0;
} else if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
st->codecpar->codec_id == AV_CODEC_ID_AC3 &&
ts->m2ts_mode) {
-*q++ = STREAM_ID_EXTENDED_STREAM_ID;
+stream_id = STREAM_ID_EXTENDED_STREAM_ID;
} else if (st->codecpar->codec_type == AVMEDIA_TYPE_DATA &&
st->codecpar->codec_id == AV_CODEC_ID_TIMED_ID3) {
-*q++ = STREAM_ID_PRIVATE_STREAM_1;
+stream_id = STREAM_ID_PRIVATE_STREAM_1;
} else if (st->codecpar->codec_type == AVMEDIA_TYPE_DATA) {
-*q++ = stream_id != -1 ? stream_id : STREAM_ID_METADATA_STREAM;
+stream_id = stream_id != -1 ? stream_id :
STREAM_ID_METADATA_STREAM;
if (stream_id == STREAM_ID_PRIVATE_STREAM_1) /* asynchronous
KLV */
pts = dts = AV_NOPTS_VALUE;
} else {
-*q++ = STREAM_ID_PRIVATE_STREAM_1;
+stream_id = STREAM_ID_PRIVATE_STREAM_1;
if (st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE) {
if (st->codecpar->codec_id == AV_CODEC_ID_DVB_SUBTITLE) {
is_dvb_subtitle = 1;
@@ -1475,6 +1475,7 @@ static void mpegts_write_pes(AVFormatContext *s, AVStream
*st,
}
}
}
+*q++ = stream_id;
header_len = 0;
if (stream_id != 0xBC && // program_stream_map
--
2.29.2
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