[MPlayer-users] Encoding problems / tips needed

[Loren Merritt]

On Sun, 1 Aug 2004, JiHO wrote:
[snip long process description]
> 4/. Do video pass 1. You can use -oac copy to ensure good sync.
> mencoder dvd://1 -alang en -oac copy -vf crop=???,hqdn3d=2:1:2 \
> -ovc lavc -lavcopts \
> vcodec=mpeg4:vbitrate=???:v4mv:mbd=2:naq:trell:cmp=3:subcmp=3:mbcmp=3\
> :vlelim=-4:vcelim=9:lumi_mask=0.05:dark_mask=0.01:autoaspect:vpass=1 \
> -noskip -skiplimit 0 -noodml -o /dev/null

> The problems:
> hicup 1/ Movie duration in step 2 has to be read from lsdvd because
> mplayer's OSD seems to give a wrong value when playing DVDs.

Or from step 1. While the duration listed in the OSD can be innacurate, if
you actually play the movie from start to finish (while extracting audio),
then the last timestamp listed on the commandline is the duration. (Unless
you're encoding something funny like multiple episodes with the timestamps
reset in between.)
Or from the size of the WAV, or the length of the Ogg.

> hicup 3/ even using nearly all the "quality providing options" of lavc
> (if you think of others, please do not hesitate)

vmax_b_frames=1 (usually significant quality gain, but has some
side-effects, including increased cpu time to decode (+5% on my computer),
and reduced compatibility with some hardware players)

preme=2:predia=-4 (helps almost as much as 'dia', and is much faster)

and several other options with smaller gains for larger speed penalties.

> at quite high bitrates
> (up to 1400), I still get some problems with the dark areas of the
> movie. the dark greys are not very well dealt with and I got big black
> squares in the darkest parts of the movie, instead of the beautiful
> gradient of dark greys I hoped (see attached picture if you don't see
> what I mean - I hope the picture is not too heavy to be sent on this
> list). does any one have a trick to make things better? some filter
> options maybe or something like this?

1) I don't see any problems in that picture, unless I turn gamma waayy up.
2) Remove dark_mask - it decreases the quality of dark areas, hoping you
won't notice.

> Remark: Alternative method for MKV with MP3 audio:
[...]
> Question: I know that 3 pass encoding is deprecated but don't you think
> this could be used?

What do you hope to gain from this alternate method? Just access to
mencoder's bitrate calc?

--Loren Merritt