Re: mulithread rework

On 24/04/2008, Michael Niedermayer <[email protected]> wrote:
> If anyone is interrested in seeing how scaleable multithreaded encoding
> based on independant slices is (or is not ...) and by how much it worsens
> the quality per bitrate. FFmpegs mpeg1/2/4/h263 encoders support
> multithreaded encoding based on independant slices.
>
> PS: for a realistic test with ffmpeg one should tweak the parameters
> as our defaults are no good quality/bitrate wise.
>
> PS2: I dont have a multi cpu system, so i actually dont know how bad
> ffmpeg scales ...

ffmpeg scales very well with cpus, and the effect on quality is so
small compared to the speed gains on a quad core that I never use
ffmpeg without multiple threads. Quality wise for equivalent
quantization and psnr vs bitrate, ffmpeg edges out xvid at the lower
quantization settings by a decent margin (that's not the case at lower
bitrates / higher quantization settings). So why am I even looking at
xvid? Well ffmpeg is not really "stable" and has random different
problems at various intervals, and, well, there was this xvid code
lying around that was screaming out for someone to have a play with
it. Also, I still see most windows users using xvid for their AVI
encoding.

--
-ck