[FFmpeg-user] Selecting/dropping frames without re-encoding

Moritz Barsnick barsnick at gmx.net
Fri Oct 7 15:06:25 EEST 2016


On Fri, Oct 07, 2016 at 13:07:53 +0200, Carl Eugen Hoyos wrote:
> 2016-10-06 17:34 GMT+02:00 Moritz Barsnick <barsnick at gmx.net>:
> > $ ffmpeg -r 25 -f concat -i concatscript.txt -c:v copy output.mxf
> 
> This scales very badly, no?

It's just a proof of concept. :) It scales nicely (linearly? or is
seeking more expensive the deeper you seek?), and works assuming you
have CFR input and output, and you know those rates, and ... , and ...
;-)

It "scales" better then writing every frame to disk and selecting every
second one by symlinking. That's 180000 intermediate files plus 90000
symlinks for one hour of video. Then I'd rather have ffmpeg seek into
the input file 90000 times. But both basically suck. I still prefer
that "select" bitstream filter. ;-)

Moritz


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