[FFmpeg-user] Suggestions for a PSNR-oriented coding

[Gavino L. Maddau]

Hi everyone.
I have to make a comparison between these codecs: MPEG-1, MPEG-2, x264, vp8 applied to some of these video sequences (CIF format):
http://trace.eas.asu.edu/yuv/
I'm going to use ffmpeg for the MPEG-1 and MPEG-2 coding, while for x264 and vp8 i'm going to use their own codecs.
The metric i'm going to use is PSNR, even if it's not as image quality correlated as other metrics (i.e. SSIM).
I looked for over the internet and i've found a good configuration for the x264 codec:
x264 --tune psnr --keyint 500 --preset placebo, two pass
I've to choose three different quality settings, which in the x264 case means switching the preset in three different ways, i.e. fast, slow and placebo.
The only thing i've to care is obtain a PSNR value higher than 30 dB (i'm going to use the MSU VQM Tool for the measurements).
I thought to translate the x264 configuration to a ffmpeg one and to use it for MPEG-1 and MPEG-2, but it doesn't seem a good idea, they are different codecs.
Then i'd like if you could suggest me a good configuration for the MPEG-1 and MPEG-2 coding through ffmpeg, and a way to switch between the three quality level.
For the vp8 configuration i'll obviously ask to the vp8 group, if you want to help me for that codec too i'd be very glad, but i don't want to annoy you with those extra deals.
Thank you in advance.