Mencoder

When compressing video on a Unix system Mencoder is an easy choice. Its a part of the Mplayer packed, that is also used in the KiSS players and therefore 100% compatible. Its also one of most widely used and therefore well supported.

With compression you can achieve up to 10 times less size and there by save a lot of disk space. The trade-off is that the quality is slightly reduced (Picture noise and compression artefacts) and that fast forwarding/rewinding doesn't work as well as with the native Mpeg2 files. But if you are not fanatical with the picture quality, it's a good deal.

There is a lot of consideration to take in to account when compressing a video. If you want the best possible quality of your compression, you will have to adjust it to the movie, as different movies should have different settings. Here I try to present the best settings, for an all-round compression of recorded TV on a KiSS player, in PAL 4:3 format. It's not as good as what aXXo dose (A pirate sharing through bit-torrent) but hopefully we will be able to share experiences here and improve on it over time?

Two pass operation There is no way around a 2 pass compression, if you want this level of compression in a reasonably quality. First pass create a log file (divx2pass.log) and throw the compressed movie output away. The logfile is the used by the 2nd pass to adjust the use of bits in the most effective way.

The complete commands:

Pass 1

mencoder -oac mp3lame -lameopts cbr:br=128 -ovc lavc  -mc 0 
-lavcopts vcodec=mpeg4:vmax_b_frames=1:vb_strategy=1:trell:mbd=2:v4mv:
last_pred=3:predia=2:dia=2:preme=2:precmp=2:cmp=3:subcmp=3:mv0:cbp:vqcomp=0.6:
vbitrate=800:vpass=1:turbo 
-vf crop=688:544:16:16,lavcdeint,hqdn3d=2:1:2
-o/dev/null <input file>

Pass 2

mencoder -oac mp3lame -lameopts cbr:br=128 -ovc lavc -mc 0 
-lavcopts vcodec=mpeg4:vmax_b_frames=1:vb_strategy=1:trell:mbd=2:v4mv:
last_pred=3:predia=2:dia=2:preme=2:precmp=2:cmp=3:subcmp=3:mv0:cbp:vqcomp=0.6:
vbitrate=800:vpass=2 
-vf crop=688:544:16:16,lavcdeint,hqdn3d=2:1:2 -ffourcc XVID  
-o<output file> <input file>