[FFmpeg-trac] #1731(avformat:new): libavformat muxers destroy initial timestamp offsets
FFmpeg
trac at avcodec.org
Thu Sep 13 14:01:19 CEST 2012
#1731: libavformat muxers destroy initial timestamp offsets
-------------------------------------+-------------------------------------
Reporter: saste | Owner:
Type: defect | Status: new
Priority: normal | Component: avformat
Version: | Keywords: muxer
unspecified | timestamp flv avi
Blocked By: | Blocking:
Reproduced by developer: 0 | Analyzed by developer: 0
-------------------------------------+-------------------------------------
Many muxers in libavformat (tested: avi, flv) destory the initial offset.
This is meant as a feature, but has the effect that remuxing a file will
destroy the original timestamp information. This is especially annoying in
case streams from different sources need to be synched.
How to reproduce:
{{{
ffmpeg -f lavfi -i "aevalsrc=sin(2*PI*400*t)::d=5,asetpts=PTS+10/TB" -y
out.flv
}
then check the packet timestamps with ffprobe -show_packets out.flv.
A possible workaround:
{{{
ffmpeg -f lavfi -i
"aevalsrc=sin(2*PI*400*t)::d=5,asetpts=PTS+10/TB,aresample=min_comp=0.001:min_hard_comp=0.0010"
-y out.flv
}}}
(with video the problem can't be easily worked around).
The behavior with respect to the initial offset could be made configurable
through some options.
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1731>
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