[FFmpeg-devel] [PATCH 00/11] CRC32 support for Matroska muxer

Jerome Martinez jerome at mediaarea.net
Thu Oct 6 15:10:31 EEST 2016

Le 06/10/2016 à 12:29, Michael Niedermayer a écrit :
> Does this reduce writing speed ?

in the same manner as e.g. reducing FFV1 writing speed with default 
configuration, i.e. with CRC per slice (same kind of job).
On my machine (i7 from 2012), CRC computing takes less than 1% of the 
CPU when I decode FFV1, so I estimate the impact of CRC on both FFV1 
level and Matroska level to less than 2% in case FFV1 is used. I don't 
think it would be a more with e.g. AVC as frame byte size is smaller.

> for example when remuxing high bitrate data like rawvideo ?

On my machine (i7 from 2012), with the "4 bytes at once" algorithm used 
by FFmpeg if I well understood FFmpeg code on this part, I benched CRC 
computing at 1 GB/s per core, so it should be more than enough also for 

CRC element could be an option as it is for FFV1, but I argue for having 
it set by default, for the same reasons it is set by default with FFV1.

> [...]

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