[FFmpeg-trac] #4789(undetermined:closed): v4l2 -ts abs not always working
FFmpeg
trac at avcodec.org
Fri Aug 21 13:14:15 CEST 2015
#4789: v4l2 -ts abs not always working
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Reporter: basinilya | Owner:
Type: defect | Status: closed
Priority: normal | Component:
Version: 2.7 | undetermined
Keywords: v4l2 | Resolution: invalid
Blocking: | Blocked By:
Analyzed by developer: 0 | Reproduced by developer: 0
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Changes (by basinilya):
* status: new => closed
* resolution: => invalid
Comment:
Replying to [comment:1 cehoyos]:
> Replying to [ticket:4789 basinilya]:
> > Duration: N/A, start: 83594.430406, bitrate: 165888 kb/s
I was looking at:
> > pts: 0 pts_time:0
Nevertheless, you are right: there's a difference in ffplay and ffmpeg.
When I grab /dev/video0 with ffplay, shown PTS starts with wallclock,
while in ffmpeg PTS starts with zero. I didn't use ffplay directly with
real device, because it crashes the device driver. Instead I piped ffmpeg
to ffplay and saw zero PTS, which confused me.
Sorry for that.
Since I do need wallclock PTS in filter expressions (but not 'time(0)',
because it's laggy) in ffmpeg, I found a workaround:
{{{
-vf "setpts='PTS+(RTCSTART/(TB*1000000))',do
stuff...,setpts='PTS-(RTCSTART/(TB*1000000))'"
}}}
--
Ticket URL: <https://trac.ffmpeg.org/ticket/4789#comment:2>
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