[FFmpeg-user] Why is concat so slow on a powerful machine?

Carlos E. R. robin.listas at telefonica.net
Thu Oct 19 19:08:42 EEST 2017

On 2017-10-19 17:51, Kevin Duffey wrote:
> So I would assume that if I can copy the two files in a matter of
> seconds from one dir to another on the SSD, that copying them together
> would be similar speed. However I did try that and it seemed to hang..
> or appear to do nothing. I unfortunately had to stop it but if it was
> working, it was taking a long while as well.
> Which now has me wondering..why? If it is just copying two files into
> one.. why is that way way slower than copying the two files to another
> location individually? A copy is a copy. It is not rendering.. it is
> merely moving the bits to another location (er.. copying them) no
> different than copying the two files individually.

Well, if concatenating two files (which is, as you say, just a file
copy) in your system fails or is slow, ffmpeg will also be slow.

I would say that your SSD can not cope with the operation, but you say
that a plain copy of the same two files to another directory in the same
disk worked fast - wait, did you try that?

Do you have another disk, rotating rust type? Try there.

Cheers / Saludos,

		Carlos E. R.
		(from 42.2 x86_64 "Malachite" at Telcontar)

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