[FFmpeg-user] Verifying lossless rewrapping/transcoding in one step?

Moritz Barsnick barsnick at gmx.net
Sat Aug 3 15:07:20 EEST 2019

On Fri, Aug 02, 2019 at 14:51:36 +0200, Peter B. wrote:
> I assume no answer means there's no option to do that.

No, there isn't.

I believe in using the right tools for the right tasks. If it can be
glued together with a script, why worry about modifying an existing
program to do the same?

That said, regarding your request, I believe the showstopper is in the
concept: To re-calculate the checksum of the output, it needs to be
decoded again. That's not something ffmpeg can do within its binary, it
can't use the output and chain it as its own input. You *can* do that
by scripting (obviously), and you could construct some program with the
libav* libraries. But at the end of the day, you want the features of
ffmpeg (the command line tool), which you can't just reeinvent. So
basically, you need to prop something into the command line tool which
can chain encodes and decodes. And that's no small task, I believe,
unlike "yet another special muxer/demuxer".

That's my take on it: Way too much effort for the gain.


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