[FFmpeg-user] DV playback rate issues, timecode is invalid

Dragan Randjelovic logicomyu at gmail.com
Tue Jan 24 18:06:16 EET 2023


Dear Stuart,

I could see video normally and audio was noticeably pitched down,

since there was no time code: [dv @ 000001c72fc2f840] Detected timecode is
invalid
I cannot know if people were moving faster, or it was just an after party :)


1.  change pcm codec to pcm_s24le in ffmpeg line.

2. try processing raw dv with ffmbc like this:

ffmbc.exe -y -i "input.dv" -vcodec copy -an "output.mov" -acodec pcm_s24le
-newaudio -map_audio_channel 0:1:0:0:1:0 -acodec  pcm_s24le  -newaudio
-map_audio_channel 0:1:1:0:2:0

and if it doesn't work, then definitely try to recapture with dv processor
in line.

P.S you may also relock video in transcoding phase


Regards.
Dragan


On Tue, Jan 24, 2023 at 3:24 PM Stuart Robinson <Stuart.Robinson at ed.ac.uk>
wrote:

>
>
> ________________________________
> From: ffmpeg-user <ffmpeg-user-bounces at ffmpeg.org> on behalf of Stuart
> Robinson <Stuart.Robinson at ed.ac.uk>
> Sent: 19 January 2023 09:04
> To: ffmpeg-user at ffmpeg.org <ffmpeg-user at ffmpeg.org>
> Subject: [FFmpeg-user] DV playback rate issues, timecode is invalid
>
> I am having terrible trouble with a long play DV I have captured that I am
> trying to transcode. It seems to be playing back slowly regardless of what
> I've tried. The original also plays back strangely, it was captured with
> ffmpeg from a dv camcorder.
>
>
>
> https://drive.google.com/file/d/1ya2C6JmbBQuRUJ_U-fJT8XODYVw0U1kr/view?usp=sharing
> [
> https://lh3.googleusercontent.com/2Z8CVgH_AoIH1LrOrsKKyOeyPmv6bNovZD9akGxW3FD_b0aqhfwUxCGUHIzzrcPW1Tg=w1200-h630-p
> ]<
> https://drive.google.com/file/d/1ya2C6JmbBQuRUJ_U-fJT8XODYVw0U1kr/view?usp=sharing
> >
> Test1.dv<
> https://drive.google.com/file/d/1ya2C6JmbBQuRUJ_U-fJT8XODYVw0U1kr/view?usp=sharing
> >
> drive.google.com
> Can someone take a look and let me know what might help? Are the first few
> frames throwing it off somehow?
>
> Thanks for any help.
>
> Stuart
>
> --
>
> Thanks,
>
> Stuart Robinson,
> __________________________________________________________________
> It looks as though this was an issue with the audio changing from 4ch
> 32kHz to 2 ch 48kHz at the start of the track due to a faulty recording
> (though it may also have had changes to the video stream), can the aac
> decoder accept changes?
>
> Answering in case anyone else has similar problems, I ended up
> re-capturing the file skipping out the bad patch at the start when the
> change happens.
>
> Stuart
>
>
> --
>
> Thanks,
>
>         Stuart Robinson,
>
>         AV Technician,
>
>         Sound Lab,
>
>         School of Scottish Studies,
>
>         University of Edinburgh,
>
>         29 George Square,
>
>         Edinburgh,
>
>         EH8 9LD
>
>
>
>         0131 651 5001
>
>
>
>
>
> The University of Edinburgh is a charitable body, registered in
>
> Scotland, with registration number SC005336.
>
>
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