[MPlayer-users] Recent lavc ratecontrol changes

[Tobias Diedrich]

Yay!

With the recent ratecontrol changes, 2-pass encoding now works well
with high bitrates and low quantizers.

Source:
Cowboy Bebop Knocking on Heavens Door Japanese RC2 Release

Commandline used (vpass=1 in pass 1):
mencoder -nosound -ovc lavc -vf pp=hb/vb/dr,hqdn3d -fps 29.97 -mc 0
-ofps 23.976 -lavcopts vcodec=mpeg2video:vqmin=1:mbqmin=1:lmin=0.1:
vbitrate=4000:vrc_minrate=400:vrc_maxrate=9000:vrc_buf_size=1835:mbd=2:
keyint=25:vmax_b_frames=2:vpsize=2000:scplx_mask=0.2:trell:precmp=2:cmp=2:
subcmp=2:cbp:mv0:psnr:vrc_eq=tex:vpass=2 dvd://1 -dvd-device /dev/cdrom
-ss 500 -endpos 30 -of mpeg -o test2.mpg

Results:
Video stream: 4006.863 kbit/s  (500857 bps)  size: 15040839 bytes 30.030 secs  720 frames
PSNR: Y:47.14, Cb:50.87, Cr:50.67, All:48.05

Bitrate viewer stats:
Peak bitrate 6607KBit, average 3774KBit
Peak qlevel 2.57, average 1.87 (more or less constant in the graph)
VBV buffer size 224KByte

The bitrate viewer average value is too low and does not match
file_size/file_duration (15040839/30 => 501361 bps) for the video stream.

It took me a bit to find the still undocumented lmin switch, which
defaults to 2.0 and limits the quantizers.

-- 
Tobias						PGP: http://9ac7e0bc.2ya.com
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