[FFmpeg-user] Need help resolving concat error

Moritz Barsnick barsnick at gmx.net
Sun Jul 24 18:16:28 EEST 2016

On Sun, Jul 24, 2016 at 16:49:30 +0200, Peter White wrote:
> <(for f in ./*.MOV; do echo "file '$PWD/$f'"; done)
> is a very fancy way of saying *.MOV. ;) Essentially that is what
> happens there:
> ffmpeg -i *.MOV

No, it isn't at all. It's a bash-ism (or perhaps zdh-ism) which
provides a pseudo file containing the output of the command within the
brackets as content. Valid approach, and it's used in the wiki as well.

This one resulting file is passed as a concat file to "-i".

But, as Cley pointed out, that file doesn't have a proper extension or
a proper header, so "-f concat" should be added as an input option.
And/or a proper header added.

> I suppose files.txt is a list of one file path per line? I believe
> this is not accepted as input by ffmpeg. It expects media files not
> text files listing those.

The original poster is using the concat demuxer, read about it in the
docs or on the wiki page link I mentioned above.

You are right though in saying that "files.txt" is being interpreted as
a multimedia file. It either needs the extension .concat (I believe),
or better "-f concat".

> Also have a look at what Cley Faye wrote in their reply. To concatenate
> files you need the concat filter. Just using "-c:v copy -c:a copy" only
> gets you what ffmpeg deems the best quality input.

That's total nonsense. You *cannot* use a filter with "-c copy".

Mark is using the concat *demuxer*, and that may just be fine.

I had said he should check the single input files first, but you
(Peter) are right in saying that ffmpeg's interpretation of files.txt
was misleading the process.


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