[FFmpeg-devel] [PATCH] Allow 'concat' filter to support inputs with different frame rates

Nicolas George george at nsup.org
Wed Mar 8 21:35:36 EET 2017

L'octidi 18 ventôse, an CCXXV, Calvin Walton a écrit :
> Hmm. Setting it to the same as the input value if all inputs match
> shouldn't be too hard, I think.
> In the actual case of inputs with different frame rates, would it be
> better to use the '1/0' value, or should it attempt to calculate a
> common framerate that's a multiple of all inputs? (e.g. for 24fps and
> 30fps inputs, it could pick 120fps).
> There's already a TODO listed in the filter code about determining a
> common timebase rather than using AV_TIME_BASE - if I'm doing the work
> to find a common framerate, I could probably do this at the same time.

If the inputs have different frame rates, then concat will be outputting
variable frame rate, not constant with a common divisor. Therefore 1/0
is better I think.

OTOH, printing a message when this happens would probably be useful, and
in that case, printing the common possible frame rate would be nice. But
is is not urgent.


  Nicolas George
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