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

Cley Faye cleyfaye at gmail.com
Wed Oct 18 11:09:36 EEST 2017

2017-10-18 3:17 GMT+02:00 Kevin Duffey <kevinmduffey-at-yahoo.com at ffmpeg.org

> Yup. I do not specify the output. I just use the same .mov file extension
> as the two source files. Is it possible even though I specify -c copy
> out.mov it is rendering and not Concat??
​You really should provide a minimal command line reproducing the issue and
the output of ffmpeg, otherwise it will be impossible to divine what's

Or, if you want a general answer, no, concat should be fast assuming that
I/O are fast and the output muxer is fast. Without more information it is
hard to say anything more.​

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