[FFmpeg-trac] #3714(avformat:open): Remuxing mpegts results in 5% bigger file size than original file
FFmpeg
trac at avcodec.org
Tue Jul 15 14:00:45 CEST 2014
#3714: Remuxing mpegts results in 5% bigger file size than original file
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Reporter: DavJames | Owner:
Type: defect | Status: open
Priority: normal | Component: avformat
Version: git-master | Resolution:
Keywords: mpegts | Blocked By:
Blocking: | Reproduced by developer: 1
Analyzed by developer: 0 |
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Comment (by AndyF):
You may find that the software that recorded the sample has heavily
reduced the PAT/PMT packets.
They do seem a lot lower than recordings I have and ISTR the recorder I
use reduced them in the past, possibly a bit now, but not by as much, if
at all, due to issues that arose from heavy reduction.
There are slight differences between the sample and the remux in the vid
and audio streams, but most of the extra size is more PAT/PMT packets and
it seems that one is duplicated with a different PID - I don't know if
that is intentional for eg. compatibility, or is an issue.
Below is some output from a (rubbish) ts analyser I cobbled together ages
ago. Apart from the dup the output from ffmpeg looks more like what I am
user to seeing than the sample.
{{{
Sample -
Total packets = 1585830 Errored packets = 0
PID Total RAI PUSI PCR PMD(ms) CFail Cut1
Cut2 Flags
0x0000 1384 0 1384 0 0 0 0
0
0x0100 1384 0 1384 0 0 0 0
0
0x0201 1555747 6 3660 3653 56 0 481150
642662 AE PD EP DI
0x0202 27314 1 6863 2 0 0 571861
0 AE PD EP DI
0x1fff 1 0 0 0 0 0 0
0
remux -
Total packets = 1668255 Errored packets = 0
PID Total RAI PUSI PCR PMD(ms) CFail Cut1
Cut2 Flags
0x0000 39671 0 39671 0 0 0 0
0
0x0011 7906 0 7906 0 0 0 0
0
0x0100 1557595 325 7320 3688 40 0 3
6095 AE PD EP DI
0x0101 23412 1706 1697 13 0 0 4877
4889 AE PD EP DI
0x1000 39671 0 39671 0 0 0 0
0
}}}
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Ticket URL: <https://trac.ffmpeg.org/ticket/3714#comment:5>
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