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

Kevin Duffey kevinmduffey at yahoo.com
Thu Oct 19 18:51:47 EEST 2017

 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.
Is there any other setting for ffmpeg, like I should specify the output codec, or something.. to ensure it is copying and not rendering?

    On Wednesday, October 18, 2017, 6:00:20 AM PDT, Carlos E. R. <robin.listas at telefonica.net> wrote:  
 On 2017-10-18 10:49, Kevin Duffey wrote:
> Thanks. Sorry I should have included that info.
> I have two files.. both are the same.. DNxHR SQ codec. Usually they are about 45mins each, sometimes different depending on if my battery died while filming! Sports games.
> They reside on an SSD drive. I am on Windows 10 Home. I have a txt file set up demux.txt. The call I do is:

To verify if the hardware is related to the problem, you can do:

copy file1.mov + file2.mov fileout.mov

Or something similar, my windows skills are rusty.

Cheers / Saludos,

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