[FFmpeg-user] ffmpeg -i reports a video of length 03:17.53, but splitting into frames at 2 fps only results in one frame

[Stéphane Chauveau]

The documenation to setpts says that the FR value may is only defined in 
constant frame-rate videos.
If its does not exists in your mpeg file then you could try something 
like 'setpts=N*30'

ps: the -vf argument in the first command in my previous message was 
supposed to be showideo (so without the setpts part).


On 7/16/19 7:20 PM, Stéphane Chauveau wrote:
> In your ffmpeg output, all frames have the same time=26:19:06.00 and 
> that could indicate an overflow in the PTS (presentation time stamp) 
> values probably because your video is part of a very long video stream.
>
> Add the filter showinfo to your command.
>
> ffmpeg -i input.mpg -vf  setpts='N*FR',showvideo  .......
>
> That should give out information about each decoded video frame. 
> Something like that
>
> [Parsed_showinfo_0 @ 0x7f5e58cfe580] n: 122 pts:   3160 
> pts_time:3.16    pos:   981301 fmt:yuv420p ...
>
> In a proper video, pts and pts_time are expected to be strictly 
> increasing. If this is not the case then you could try to reassign the 
> pts using the setpts filter.
>
> ffmpeg -i input.mpg  -vf  setpts='N*FR',showvideo   .......
>
> I am not sure that 'N*FR' is the appropriate formula. The idea is to 
> recreate a pts value that makes sense. (N=the frame numeber, FR=the 
> framerate).
>
> See http://ffmpeg.org/ffmpeg-all.html#setpts_002c-asetpts for the 
> other variables that can be used in setpts.
>
> PS: When I use setpts=10000 on a valid video, I only get 1 output jpeg 
> file so that tells me that a constant pts could be the problem.
>
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