[MPlayer-users] Problem Encoding Solid Color Objects With LAVC MPEG4

[Angel]

I've reported this problem before but nothing really came of it. I more or 
less dismissed the problem as being a limitation of mpeg4/bitrate etc. 
However, I recently encoded the movie Bad Boys and during one of the scenes 
there is a solid colored background behind one of the characters and it came 
out looking like an 8 puzzle with large blocks shifting around. I decided to 
try encoding the movie using DIVX 5.1 and virtualdub just to see how the 
results would compare. To my extreme disappointment... the DIVX 5.1 version 
looked 1000% better. The background looks kind of noisy (as it should) and 
there are no large blocks moving around. Just for the hell of it... I also 
tried encoding it using mencoder/xvid. The results were very similar to the 
DIVX 5.1 results. I don't know if I should report this here or to the ffmpeg 
list. I am willing to upload the source/results if that would be helpful. 
Just for reference, here are the encoding parameters used:

LAVC Command Line:

mencoder stream.dump \
-oac pcm \
-ovc lavc \
-lavcopts vcodec=mpeg4:vbitrate=1500:\
vhq:keyint=300:trell:qpel:vmax_b_frames=1:mbqmin=1:\
vqmin=1:vqmax=31:vpass=1 \
-vf scale=650:-2,crop=640:352:4:5 \
-zoom \
-sws 2 \
-ofps 23.976 \
-o /dev/null

mencoder stream.dump \
-oac pcm \
-ovc lavc \
-lavcopts vcodec=mpeg4:vbitrate=1500:\
vhq:keyint=300:trell:qpel:vmax_b_frames=1:mbqmin=1:\
vqmin=1:vqmax=31:vpass=2 \
-vf scale=650:-2,crop=640:352:4:5 \
-zoom \
-sws 2 \
-ofps 23.976 \
-o movie.avi

Xvid Command Line (using CVS version):

mencoder stream.dump \
-oac pcm \	
-ovc xvid \
-xvidencopts bitrate=1500:hq_ac:4mv:vhq=4:qpel:\
mpeg_quant:max_key_interval=300:pass=1 \
-vf scale=650:-2,crop=640:352:4:5 \
-zoom \
-sws 2 \
-ofps 23.976 \
-o /dev/null

mencoder stream.dump \
-oac pcm \	
-ovc xvid \
-xvidencopts bitrate=1500:hq_ac:4mv:vhq=4:qpel:\
mpeg_quant:max_key_interval=300:pass=2 \
-vf scale=650:-2,crop=640:352:4:5 \
-zoom \
-sws 2 \
-ofps 23.976 \
-o movie.avi

Divx 5.1:

Performance / Quality = Standard
2-Pass Mode
Bitrate = 1500kbps
B-Frames,Qpel,GMC enabled
Psychovisual Enhancements Disabled
Pre Processing Disabled
Keyframe Interval = 300

-Angel