[FFmpeg-user] is variable quantization per macroblock supported in mpeg2video codec?

[Richard Buteau]

Hi all,
I am trying to get best possible video quality in one pass with mpeg2video encoder for 1080i at low bitrate in CBR.

I can only get fix quantization per frame when I used mpeg2video.
Is variable quantization per macroblock supported in mpeg2video codec?
If so how do I turn this feature on?

Here is the command line I am using right now.
-vcodec mpeg2video -bf 3 -b:v 5740000 -flags +ildct+ilme  -dia_size 1024 -trellis 2 -cmp 2 -subcmp 6 -muxdelay 1.000000 -keyint_min 0 -minrate 5740000 -maxrate 5740000 -bufsize 4177920  -g 60

Also I also been playing around with -dia_size and value of 1024 give slightly higher PSNR but I haven't seen a noticeable difference in the clip.
Any suggestions on improving these settings would be appreciated.