[FFmpeg-trac] #9494(undetermined:new): Seeking in MPEG TS with copyts overflows for 13+ hours

FFmpeg trac at avcodec.org
Thu Nov 4 10:18:12 EET 2021

#9494: Seeking in MPEG TS with copyts overflows for 13+ hours
             Reporter:  Radek        |                    Owner:  (none)
  Hladík                             |
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  git-master   |               Resolution:
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
Comment (by Radek Hladík):

 Replying to [comment:1 Balling]:
 > >I know that mpegts timestamp have the resolution of cca 26.5 hours, but
 this problem occurs exactly in the half.
 > Not that simple, 2^33 / 90000 seconds = 26 hours 30 minutes 43.718
 seconds. There is rollover support, but not perfect. #7876, #7449, #8689.

 I did not want to clutter the original ticket message with the rollover
 too much as I think that it is an unrelated problem. I've read through a
 lot of tickets in this tracker before posting, I even tried the patch from
 #7876 and it did not change a thing.

 As far as I understand the rollover, the pts is 33-bit long unsigned
 number with 90000 timebase. However my problem occurs almost exactly at
 2^32^ /90000=4294967296/90000  = 47721.85884 seconds = 13.2560719012346
 hours. So it looks like to me that the 33rd bit gets lost somewhere and/or
 is converted into sign but I do not want to speculate as I do not know the
 ffmpeg code....

 Also if I just copy the whole file without seeking, then everything works

 % ffmpeg  -i 16hours.ts   -c copy -copyts test_copy_ts.ts >a6 2>&1


 and even the progress time is fine:
 frame=1440000 fps=76557 q=-1.0 Lsize= 1200748kB time=15:59:59.99 bitrate=
 170.8kbits/s speed=3.06e+03x
Ticket URL: <https://trac.ffmpeg.org/ticket/9494#comment:2>
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