[MPlayer-users] Suggested Low Bitrate Encoding Options

[RC]

I've spent about a week trying to make lavc not look like crap at
very low bitrates, and I've finally worked out something that is
decent.  FMP4 with these options looks much, much better (sharper) than
Xvid, though with just slightly more artifacts...  I found it very sad
that Xvid quantizes out most of the stars, in a movie that takes place
in space.

Even with my best efforts, both codecs still get easily beaten at low
bitrates by (the rather old) VP3.2, which is then surpassed by x264.


Preferred lavcopts, followed by comments:

v4mv:trell:mbd=2:mv0:cbp:dia=-6:predia=-1:last_pred=3:nr=300:vqcomp=0.6
:scplx_mask=0.2:tcplx_mask=0.1:dark_mask=0.1:lumi_mask=0.2
:border_mask=0.3:naq:vlelim=50:vcelim=-4:vmax_b_frames=2:brd_scale=3
:bidir_refine=4:vb_strategy=2:mpeg_quant
:intra_matrix=8,16,19,22,26,27,99,99,16,16,22,24,27,29,99,99,19,22,26,
27,29,34,99,99,22,22,26,27,29,34,99,99,22,26,27,29,32,35,99,99,26,27,29,
32,35,40,99,99,26,27,29,34,38,99,99,99,27,29,35,38,99,99,99,99
:inter_matrix=16,17,18,19,20,21,99,99,17,18,19,20,21,22,99,99,18,19,20,
21,22,23,99,99,19,20,21,22,23,24,99,99,20,21,22,23,25,26,99,99,21,22,23
,24,26,99,99,99,22,23,24,26,99,99,99,99,23,24,25,99,99,99,99,99

I'd really like a large vqcomp for fast reaction, but ratecontrol goes
screwy.  I seriously considered rewriting the ratecontrol equation for a
while there, when I was fighting with it.

Remove *_mask options (or lower by 0.1) for high/medium bitrate
encodes.

vlelim might not be ideal.  99 seemed a bit blocky, so I tried 50. 
It's better than 0, and I didn't notice artifacts.  Don't touch vcelim,
though.

2 b-frames looks much better than 0 or 4.  Should test with 1. A b-frame
speed-up could really help, as they half encoding speed in my tests.  I
didn't yet test strategy=1/0, or lower "refine" values.

That quantitizer is "Angel best very low".  I tested 2 dozen different
quants on multiple videos, and Angel's are the only ones that
effectively suppresses quantization noise, while otherwise keeping the
picture sharp (unlike Xvid).  It makes a huge difference just by itself,
and seems to work pretty well with any content, at any bitrate, entirely
unlike the *_mask options.