[FFmpeg-user] theoretical concurrency limitations

[Anatol]

Sorry for the top-post, unintentionally.

The high thread count caused significant quality reduction with older
ffmpeg/x264 encoders.
I'll run some tests with the newer versions and post the results.

In most cases there is no reason for multi threaded decoding.
On the other hand 4 threaded x264 encoding runs 2.5-3 times faster than a
single threaded encoding, assuming that there are enough free CPU.
With 4 threads the quality insignificantly lower, almost invisible.
Unfortunately, I did not keep the PSNR results.