[FFmpeg-devel] [PATCH v2] ffmpeg: allow full range of dts_delta_threshold

[Michael Niedermayer]

On Wed, Apr 15, 2020 at 10:55:47AM +0530, Gyan Doshi wrote:
> 
> 
> On 15-04-2020 01:33 am, Michael Niedermayer wrote:
> >On Tue, Apr 14, 2020 at 02:48:47PM +0530, Gyan Doshi wrote:
> >>For inputs from demuxers with AVFMT_TS_DISCONT flag,
> >>the existing condition,
> >>
> >>   delta < -1LL*dts_delta_threshold*AV_TIME_BASE
> >>
> >>is rendered superflous due to the fixed threshold in
> >>
> >>pkt_dts + AV_TIME_BASE/10 < FFMAX(ist->pts, ist->dts)
> >>
> >>This prevents users from setting a high threshold to
> >>avoid discontinuity correction due to errant timestamps.
> >>
> >>Now, the maximum of the two thresholds is used.
> >>
> >>fate-mpeg4-resolution-change call changed to preserve existing
> >>timestamp correction by ffmpeg.c
> >>---
> >>Tested with multiple satellite MPEG-TS inputs.
> >>
> >>  fftools/ffmpeg.c     | 2 +-
> >>  tests/fate/mpeg4.mak | 2 +-
> >>  2 files changed, 2 insertions(+), 2 deletions(-)
> >breaks:
> >./ffmpeg -i 'concat:angels.mpg|angels.mpg'  -vsync 0  file.avi
> >
> >...
> >frame=   24 fps=0.0 q=12.5 Lsize=     215kB time=00:00:07.50 bitrate= 234.7kbits/s speed=75.5x
> >video:84kB audio:110kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 10.697786%
> >
> >vs.
> >
> >...
> >[avi @ 0x5601caccc180] Non-monotonous DTS in output stream 0:1; previous: 219, current: 86; changing to 220. This may result in incorrect timestamps in the output file.
> >[avi @ 0x5601caccc180] Non-monotonous DTS in output stream 0:1; previous: 220, current: 87; changing to 221. This may result in incorrect timestamps in the output file.
> >[avi @ 0x5601caccc180] Non-monotonous DTS in output stream 0:1; previous: 221, current: 88; changing to 222. This may result in incorrect timestamps in the output file.
> >[avi @ 0x5601caccc180] Non-monotonous DTS in output stream 0:1; previous: 222, current: 89; changing to 223. This may result in incorrect timestamps in the output file.
> >[avi @ 0x5601caccc180] Non-monotonous DTS in output stream 0:1; previous: 223, current: 90; changing to 224. This may result in incorrect timestamps in the output file.
> >[avi @ 0x5601caccc180] Non-monotonous DTS in output stream 0:1; previous: 224, current: 91; changing to 225. This may result in incorrect timestamps in the output file.
> >[mpeg4 @ 0x5601cac87540] Invalid pts (72) <= last (83)
> >Video encoding failed
> 
> Yes, if the input includes a mid-stream dts reset of gap less than the
> default value of dts_delta_threshold then timestamps won't be made
> continuous. Default value is 10 seconds but till now it wasn't enforced for
> negative jumps, so your command worked. With this change, user will have to
> set it manually if they expect smaller jumps.

Negative jumps should always be a discontinuity more or less.
What are you trying to fix exactly ?

is this about bitstream errors in the timestamps ?

thx

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you fake or manipulate statistics in a paper in physics you will never
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