[FFmpeg-devel] Filter with external image manupilation?

[Evert Vorster]

I thank you for the very prompt reply.


This is more of a question for ffmpeg-user, actually.
>
My apologies!

>
> > Is it possible to pause decoding and encoding of a file with a script?
>
> You can suspend ffmpeg with a signal. But that won't be very precise in
> terms of timing.
>
Ctrl+z? I'll have to educate myself on that. Does this work for encoding,
too?


>
> > During the pause between the frames, we want to manipulate the extracted
> > frame. This is done with other tools in a script. The manipulations is
> with
> > a hugin template, Panotool's nona and enblend, so it's a little outside
> of
> > what ffmpeg filters can do. (I think?)
>
> I guess there's no such filter (yet).
>
Now that would be awesome. I am sure we are doing things very
inefficiently. All the frames are transformed in exactly the same way.


> > The ultimate aim of this is to avoid eating many gigabytes of disk space
> by
> > completely expanding a input video into lossless frames.
>
> I suggest to extract the frames to stdout using the image2pipe format,
> and pipe that output to a wrapper script which (somehow) detects a
> completed frame and passes it on to your processing chain. If you block
> the output pipe once a complete frame has been received, ffmpeg should
> pause processing; once you continue to pull data from the pipe, ffmpeg
> will continue to process.
>
> I just quickly checked by piping ffmpeg's image2pipe format to "less",
> and it seems that ffmpeg only continued to process when I allowed
> "less" to read more input.
>
> Try if that works for you. The wrapper may not be trivial though.
>
Thank you very much for this valuable information. I will have a play with
it.

Kind regards,
Evert