bundled ffmpeg isn't multithreaded

[RMerlin]

Hi,

The version of ffmpeg bundled with Mezzmo 2.1.8 isn't multithreaded (or at least the libx264 library linked with isn't).

I modified a device profile to use -threads 8 (default was -threads 4). This is my CPU usage (i7 860: 4 phy cores + 4 HT threads) while transcoding using the Conceiva bundled ffmpeg:



This one is while using a static build from http://ffmpeg.arrozcru.org/autobuilds/ :



The test was done with the same sample file in both case (an MPEG2 AC3 being transcoded to libx264 and AC3)

On a related subject, a suggestion: add an option to Mezzmo to determine the number of threads to use, and pass that information to ffmpeg instead of hardcoding it into device profiles. I would suggest querying the PC to determine how many CPU threads are supported by the computer, then offer the user to select between 1 and the number of threads available, with the addition of "Auto" (as the default option), which would automatically pass the maximum number of threads to ffmpeg.