[MPlayer-users] mediocre results when dvd-ripping/encoding

Arpi arpi at thot.banki.hu
Sat Jul 6 16:38:44 CEST 2002


Hi,

> Recommended video bitrate for 700MB CD: 751
> 
> mencoder From_Russia_With_Love.avi -oac copy -ovc lavc -lavcopts
> vcodec=mpeg4:vbitrate=751:vhq:vqmin=1:vqmax=31:vpass=1 -vop
> scale=640:400 -sws 2 -o movie.avi
> 
> ^^^^^^^^ no...br is toooo low! i get a result of a much smaller
> file--about 500-600MB, not the 700MB i want... So I try a higher one...

strange. maybe the original ai file (you encode from) is too bad?

i've done several encoding, mostly from 2/3 svcd (400x400 or 400x576 source)
or 2 vcd (352x240x30fps) and i always got exactly (+-100kB!) the wanted
size, but the quality was not statisfying.

i've also found that for vcd->mpeg4, i get much better quality if i
upscale(!) the video while encoding, to eg 512x320 or so.
it seems that lavc mpeg4 codec (nor divx4) produces high quality at low
resolutions.

or maybe we just expect too much at 600-800 kbit...

2-pass video encoding should solve this, by using very high bitrate for
action scenes, and very low for slideshow ;) but i don't get much better
result with 2-pass than 1-pass. probably i should tune 2-pass with those
parameters, but i had no time to do it yet. anyway there are 3 algos for
2-pass control, 0/1/2, 2 is the default but i've found 1 i much better.

maybe someone with a good sample file (good quality source, ~15% action 75%
slowmotion) should make several test and find out how those parameters 
affect the results.

> mencoder From_Russia_With_Love.avi -oac copy -ovc lavc -lavcopts
> vcodec=mpeg4:vbitrate=1000:vhq:vqmin=1:vqmax=31:vpass=1 -vop
> scale=640:400 -sws 2 -o movie.avi
> 
> I still don't get the quality i want, and have seen in other 700MB AVIs.
> Also: two things...
> 
> 1. Why is the br i get after using lame to encode my audio too low?
it is not too low, it's ok
compare the requested and the resulting bitrate of video.
i always got the requested rate, but there were many reports on this list
saying it roduces much smaller rate, dunno why. vqmin=1 usually solved
these.

> 2. In case youre wondering, from russia with love is not some weird
> porno or something...it's one of the origional james bond 007 movies...
> If you don't believe me, look it up at amazon.com :)
:)


A'rpi / Astral & ESP-team

--
Developer of MPlayer, the Movie Player for Linux - http://www.MPlayerHQ.hu




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