[vlc] parameters for H264 encoding with x264

[Aurele]

Dear all,

I'm working with VLC 0.8.6h on ubuntu Gutsy.
I need some precisions with H264 encoding.
when i use for example: --sout 
"#transcode{vcodec=h264,vb=1024,scale=1,venc=x264{psnr=1}}:std{access=file,mux=mp4,dst="test"}"
what is the exact syntax for psnr option in the x264 module.If i want to 
enable PSNR computation, what should i use; psnr=1 or just psnr. And 
also, if i want to disable cabac for example: cabac=0 or no-cabac

Any idea or suggestion is welcome.

Thanks,

Aurele