[FFmpeg-user] Lavfi video generator slow performance

Carl Zwanzig cpz at tuunq.com
Fri Apr 6 07:56:29 EEST 2018

A few things-

On 4/5/2018 9:23 PM, Elliott Balsley wrote:
> I have 8 SSDs in RAID5 on a LSI 9361 SAS controller, formatted as NTFS.
> I got the 3000 number from AJA System Test.  That test was writing a
> single file, so probably performance would drop when writing lots of
> small files.  I will benchmark again with small files.
Writing to RAID5 is really only as fast as a single drive since for every 
block written, it has to write that data, read the entire stripe, 
calculate/write the new parity. (And RAID5 is generally considered to be 

I wouldn't trust Aja's number; download a copy of 'fio' and use that (or one 
of the several windows-based disk benchmarks). Since you're doing lots of 
"small" files, the file system overhead will be really eat into the throughput.

> This machine has 28 real CPU cores, so I’m wondering if ffmpeg or lavfi
> is limited to one core?
Use SysInternals "process explorer" to watch the individual cores while 
coding; it's much better than the windoze task manager.

All of these are readily find-able via google :).

Do you _really_ need a bunch of identical TIFF files? If they're all the 
same, make one file and use a script to copy/rename it a bunch of times. 
(And TIFFs are huge compared to other still image formats anyway.)



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