On Sun, Jan 14, 2024 at 8:24 AM Mark Filipak <[email protected]> wrote: > > This is not the way to do things, Andrew. > > Please do not add your notice of a trac ticket submission to my reply. It has > nothing to do with my > reply. > > Your ticket has justifiably been closed. > > Trac is not a place to get extra help. It is for bug reporting. Instead to a > trac ticket, post your > concerns here and try to gain help/confirmation/clarification here.
well, at least it was closed with explanation: ============ There is a limitation with time value displays in showinfo but this is not it. showinfo uses a field width of 7 characters, so it can and does display e.g. 2.96667. When there are fewer characters shown, it means the remaining digits are 0 i.e. pts_time:1 indicates 1.00000. As for ffprobe, using the bare command will just show the input dump (same as ffmpeg) which is meant to be a summary display. For precision, you should use the sectional display. For input container duration, you would use ffprobe -show_entries format=duration -i INPUT which will print with microsecond precision, e.g. [FORMAT] duration=179.468005 [/FORMAT] ====== this is valuable information > > --Mark. > > On 13/01/2024 22.11, Andrew Randrianasulu wrote: > > On Sat, Jan 13, 2024 at 10:27 PM Mark Filipak > > <[email protected]> wrote: > >> > >> On 13/01/2024 12.50, Andrew Randrianasulu wrote: > >>> On Sat, Jan 13, 2024 at 8:57 PM Def Etienne <[email protected]> wrote: > >> -snip- > >>>> ffmpeg -i ~/6029.mp4 -copyts c:v copy -c:acopy -t 64.600 > >>>> dev/shm/6029_cut.mp4 > >> > >> According to Devon Heitmueller -- thanks again, Devon -- '-copyts' and > >> '-muxdelay 0' are _both_ needed. > >> > >> '-copyts' -- before the input -- bypasses a routine that apparently is > >> named "tsfixup". > >> > >> '-muxdelay 0' -- after the input -- bypasses another ts fixup that > >> defaults to adding 0.7 seconds to > >> the timestamps. > >> > >> Exactly why ffmpeg does those fixups is a mystery. > >> > >> I can confirm that when cutting off the beginning: > >> ffmpeg -copyts -ss ... -i ... -c copy -muxdelay 0 ... > >> works. It preserves the timestamps (DTS, PTS). > >> > >> > >> Regarding cutting off the ending: > >> ffmpeg -to ... -i ... -c copy ... > >> I am trying to determine the behavior of '-to'. Is it PTS? Or is it ticks > >> (i.e., duration in > >> timebase units)? And does ffmpeg do fixups for '-to' clauses, also? It > >> appears there are such '-to' > >> fixups. > >> > >> > >> Also be aware that MPV rounds time, and rounds to milliseconds whereas > >> ffmpeg truncates time and > >> truncates frame numbers, DTSs, and PTSs. So times from MPV may miss an > >> I-frame in ffmpeg. What I do > >> is use MPV times to find approximate frame number. Then I use '-vf > >> showinfo' to find exact frame > >> number. Then I compute exact DTS and exact PTS from exact frame number. > >> Then I convert DTS and PTS > >> to nanoseconds in the '-ss' clause. > > > > I added ticket about ffprobe/vf_showinfo displaying truncated duration: > > > > https://trac.ffmpeg.org/ticket/10799#ticket > > > > > >> > >> Why does 'ffmpeg -ss' use times instead of relative timebase ticks (i.e. > >> durations) or absolute DTSs > >> and PTSs? Your guess is as good as mine, but it is a super PITA. > >> > >> Why does ffmpeg apply ts fixups? Your guess is as good as mine, but it is > >> a super PITA. > >> > >> > >> Also, be aware that in this listing: > >> > >>> [Parsed_showinfo_0 @ 0xee202580] n:1612 pts:5803200 ... > >> > >> the reported PTS is _not_ PTS. It is ticks (i.e., duration in timebase > >> units) that is marked "pts" > >> but isn't -- another super PITA. > >> > >> > >> Also, remuxing from M2TS to MP4 for example, applies more unknown fixups > >> even when they have the > >> exact same timebase -- another super PITA -- so don't change packet type > >> until the very end of your > >> timming and concatenating. > >> > >> --Mark. > > > _______________________________________________ > ffmpeg-user mailing list > [email protected] > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". _______________________________________________ ffmpeg-user mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
