There are ffmpeg instances/process and there are threads, although u did not ask about them. ffmpeg/x264 tends to use all existing CPU cores (Linux) to run a thread for every ffmpeg instance/process. This means that if u have 24 or 32 cores ffmpeg will run 24/32 concurrent x264 encoding threads. And this is HIGHLY un-recommended due to severe quality reduction. Use at most 4-5 threads (via '-threads' operand) for every ffmpeg process.
According to my tests u can quite safely run number of ffmpeg processes that is up to twice the number of CPU cores - 48 ffmpegs for server with 24 CPU For higher factor (>2) the overhead becomes more significant. At factor 4 and higher, the run-time is doubled and some of the processes crashed. It is possible that this kind of misbehavior was caused by disk NFS problems, I did not go that far to investigate those issues. There was no difference between 1 threaded and 4 threaded processes. Tested with ffmpeg 2.3.1/2.7.2. Although, I don't know how ffmpeg 3+ and newer x264 behaves, but I think that it works the same On Fri, Sep 16, 2016 at 2:00 PM, Carl Eugen Hoyos <[email protected]> wrote: > 2016-09-16 4:29 GMT+02:00 James Heliker <[email protected]>: > > > Basically, can someone tell me what factors should be considered > > when determining how many instances of FFmpeg can be run > > concurrently (efficiently) on a single machine? > > You mean apart from cpu, memory and disk bandwidth? > (Assuming you are not using hardware acceleration.) > > Carl Eugen > _______________________________________________ > ffmpeg-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". > _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
