My current mencoder methodology:

[evade]

I encode xvid with mencoder and this is how do it for ntsc non-interlaced content which is the bulk of what I do. Suggestions comments and quesitons are welcome.

I use xvid's ability to store aspect ratio and I also use the mencoder modules support for autoaspect which appeared in the mplayer CVS on feb 4 a recent cvs build of mplayer.

First I rip the DVD. I do this with dvd::rip because it has a nice interface for pgc ripping and has a gui for bitrate calculation.
From the transcode screen on dvd::rip I select target size and the audio track I am going to use, note the resulting video bitrate. I can now close dvd::rip discarding the project.

The Rest is done on the command line
First I cd into the directory where the vobs are and store the bitrate in a file so I don't have to remember it


dave@hammer 001 $ cd /raid/dvdrip/data/zeroeffect/vob/001/
dave@hammer 001 $ echo 1296 > bitrate

Then I determine how much I need to crop with this command (I use the second vob so the opening credits don't confuse the filter)

dave@hammer 001 $ mencoder -ovc lavc -oac copy -o /dev/null -vf cropdetect zeroeffect-002.vob

This outputs a suggested crop. I run this command with lavc because it doesn't require and options, quicker to type. Let it run for a about thirty seconds and the run the same command on the third vob, if the values differ its usually due to some very dark scenes and it is a safe bet to take the larger of the two.
( if you want to preview the crop run mplayer with the -vf crop option. I find this unnescessary as the cropdect filter does a great job.)

This movie doesn't need cropping but for examples sake I am putting a crop filter in which takes nothing off.
So now I generate some samples with this script called xvid-samples:

dave@hammer 001 $ /export/scripts/xvid-samples `pwd` Zero_Effect '-vf crop=720:480:0:0'

or if I want to use a noise filter

dave@hammer 001 $ /export/scripts/xvid-samples `pwd` Zero_Effect '-vf crop=720:480:0:0,hqdn3d'

xvid-samples:

#!/bin/tcsh
# ${1}=path to vobs
# ${2}=name of movie
# ${3}=extra (eg -vf crop=)
cd ${1}
mkdir samples
@ br=`cat bitrate`
# hvs-good matrix
echo "`date` ${2}.hvs-good.avi start encoding" >> xvid-samples.log
mencoder -o /dev/null -ofps 23.976 -ovc xvid -xvidencopts pass=1:packed=1:turbo=1:vhq=1:quant_intra_matrix=/export/scripts/hvs-good.intra.txt:quant_inter_matrix=/export/scripts/hvs-good.inter.txt:autoaspect ${3} -endpos 2:00 -aid 128 -oac copy *2.vob
echo "`date` ${2}.hvs-good.avi Pass 1 complete" >> xvid-samples.log
mencoder -o samples/${2}.hvs-good.avi -ofps 23.976 -ovc xvid -xvidencopts pass=2:packed=1:turbo=1:vhq=1:bitrate=$br\:quant_intra_matrix=/export/scripts/hvs-good.intra.txt:quant_inter_matrix=/export/scripts/hvs-good.inter.txt:autoaspect ${3} -endpos 2:00 -aid 128 -oac copy *2.vob
echo "`date` ${2}.hvs-good.avi Finished encoding" >> xvid-samples.log
# hvs-better matrix
echo "`date` ${2}.hvs-better.avi start encoding" >> xvid-samples.log
mencoder -o /dev/null -ofps 23.976 -ovc xvid -xvidencopts pass=1:packed=1:turbo=1:vhq=1:quant_intra_matrix=/export/scripts/hvs-better.intra.txt:quant_inter_matrix=/export/scripts/hvs-better.inter.txt:autoaspect ${3} -endpos 2:00 -aid 128 -oac copy *2.vob
echo "`date` ${2}.hvs-better.avi Pass 1 complete" >> xvid-samples.log
mencoder -o samples/${2}.hvs-better.avi -ofps 23.976 -ovc xvid -xvidencopts pass=2:packed=1:turbo=1:vhq=1:bitrate=$br\:quant_intra_matrix=/export/scripts/hvs-better.intra.txt:quant_inter_matrix=/export/scripts/hvs-better.inter.txt:autoaspect ${3} -endpos 2:00 -aid 128 -oac copy *2.vob
echo "`date` ${2}.hvs-better.avi Finished encoding" >> xvid-samples.log
# hvs-best matrix
echo "`date` ${2}.hvs-best.avi start encoding" >> xvid-samples.log
mencoder -o /dev/null -ofps 23.976 -ovc xvid -xvidencopts pass=1:packed=1:turbo=1:vhq=1:quant_intra_matrix=/export/scripts/hvs-best.intra.txt:quant_inter_matrix=/export/scripts/hvs-best.inter.txt:autoaspect ${3} -endpos 2:00 -aid 128 -oac copy *2.vob
echo "`date` ${2}.hvs-best.avi Pass 1 complete" >> xvid-samples.log
mencoder -o samples/${2}.hvs-best.avi -ofps 23.976 -ovc xvid -xvidencopts pass=2:packed=1:turbo=1:vhq=1:bitrate=$br\:quant_intra_matrix=/export/scripts/hvs-best.intra.txt:quant_inter_matrix=/export/scripts/hvs-best.inter.txt:autoaspect ${3} -endpos 2:00 -aid 128 -oac copy *2.vob
echo "`date` ${2}.hvs-best.avi Finished encoding" >> xvid-samples.log
# mpeg matrix
echo "`date` ${2}.mpeg.avi start encoding" >> xvid-samples.log
mencoder -o /dev/null -ofps 23.976 -ovc xvid -xvidencopts pass=1:packed=1:turbo=1:vhq=1:quant_type=mpeg:autoaspect ${3} -endpos 2:00 -aid 128 -oac copy *2.vob
echo "`date` ${2}.mpeg.avi Pass 1 complete" >> xvid-samples.log
mencoder -o samples/${2}.mpeg.avi -ofps 23.976 -ovc xvid -xvidencopts pass=2:packed=1:turbo=1:vhq=1:bitrate=$br\:quant_type=mpeg:autoaspect ${3} -endpos 2:00 -aid 128 -oac copy *2.vob
echo "`date` ${2}.mpeg.avi Finished encoding" >> xvid-samples.log
# h263 matrix
echo "`date` ${2}.h263.avi start encoding" >> xvid-samples.log
mencoder -o /dev/null -ofps 23.976 -ovc xvid -xvidencopts pass=1:packed=1:turbo=1:vhq=1:quant_type=h263:autoaspect ${3} -endpos 2:00 -aid 128 -oac copy *2.vob
echo "`date` ${2}.h263.avi Pass 1 complete" >> xvid-samples.log
mencoder -o samples/${2}.h263.avi -ofps 23.976 -ovc xvid -xvidencopts pass=2:packed=1:turbo=1:vhq=1:bitrate=$br\:quant_type=h263:autoaspect ${3} -endpos 2:00 -aid 128 -oac copy *2.vob
echo "`date` ${2}.h263.avi Finished encoding" >> xvid-samples.log


This produces 2 minute samples from the movie encoded at my desired bitrate with good better and best hvs matrices as well as mpeg and h263.

If I was unhappy with this particular sample I could do this to grab a different two minutes from 20 minutes later:

dave@hammer 001 $ /export/scripts/xvid-samples `pwd` Zero_Effect '-vf crop=720:480:0:0 --ss 20:00'

More often than not I will choose an hvs matrix so I run my xvid-hvs script with the following command:

dave@hammer 001 $ /export/scripts/xvid-hvs `pwd` Zero_Effect best '-vf crop=720:480:0:0'

Or if I am sshing into my box I will daemonize it with the at command, this also runs the process at a nice level of 2.

dave@hammer 001 $ echo "/export/scripts/xvid-hvs `pwd` Zero_Effect best '-vf crop=720:480:0:0'" | at now

Or add it to a batch and run it with other jobs

dave@hammer 001 $ echo "/export/scripts/xvid-hvs `pwd` /raid/movies/Zero_Effect.avi best '-vf crop=720:480:0:0'" >> ~/batch.txt

and later run them all at 1am while I am sleeping:

dave@hammer 001 $ at -f ~/batch.txt 01:00

here is xvid-hvs:

#!/bin/tcsh
# ${1}=path to vobs
# ${2}=filename
# ${3}=hvs matrix
# ${4}=extra options eg -vf crop
cd ${1}
@ br=`cat bitrate`
echo "`date` ${2} start encoding" >> encode.log
cat *.vob | mencoder -o /dev/null -ofps 23.976 -ovc xvid -xvidencopts pass=1:packed=1:vhq=1:quant_intra_matrix=/export/scripts/hvs-${3}.intra.txt:quant_inter_matrix=/export/scripts/hvs-${3}.inter.txt:autoaspect ${4} -aid 128 -oac copy -
echo "`date` ${2} Pass 1 complete" >> encode.log
cat *.vob | mencoder -o ${2} -ofps 23.976 -ovc xvid -xvidencopts pass=2:packed=1:vhq=1:bitrate=$br\:quant_intra_matrix=/export/scripts/hvs-${3}.intra.txt:quant_inter_matrix=/export/scripts/hvs-${3}.inter.txt:autoaspect ${4} -aid 128 -oac copy -
echo "`date` ${2} Finished encoding" >> encode.log

[unixfs]

- One of the main filter developers always suggests to crop at x16 boundaries (if necessary) to prevent the misalignment of the chroma plane, even at the expense of few rows of film.

- I never saw any difference between vhq=1 and vhq=0 (that is much
faster).

- actually xvid encodes 2 b frames by default; I often saw bad things
with b-frames enabled

[evade]

Thank you unixfs, exactly the kind of feedback I was hoping for.

So that is multiples of 16 for width and height? If cropdetect says:
(-vf crop=718:346:0:66) would you do -vf crop=720:336:0:66 ?

At some point the xvid/mencoder module developers developers made vhq=1 and 2 bframes the default. I will do some tests and see which I prefer.

Have you noticed any differences going higher like vhq=2 or vhq=4?

[unixfs]

Originally posted by evade
Thank you unixfs, exactly the kind of feedback I was hoping for.

So that is multiples of 16 for width and height? If cropdetect says:
(-vf crop=718:346:0:66) would you do -vf crop=720:336:0:66 ?

Maybe it's better to use -vf crop=720:352:0:64: not only the size should
be x16m but the offsets too (that's why I was talking of chroma plane misalignment)

At some point the xvid/mencoder module developers developers made vhq=1 and 2 bframes the default. I will do some tests and see which I prefer.

Have you noticed any differences going higher like vhq=2 or vhq=4?

I never tested xvid with vhq > 1

[unixfs]

Sorry, wrong informations.
This thread in enlightening (esp. the first answer)

http://www.mplayerhq.hu/pipermail/mp...ch/043325.html

So cropping offsets should be simply even for horizontal and x4
(in case of interlaced or telecined content) for vertical resolution.

[evade]

I have been reading a bunch on the mplayer user list, this thread and others. The rules to follow seem to be:

1) crop the movie at even numbers.

2) offsets must be even. (except for interlaced content, which must be by 4)

3) The movie you encode should have width and height in multples of 16.


following these guidlines with a cropdetect result of -vf crop=718:346:0:66.

I want to encode at multiples of 16 height and width. I can reach that goal through any combination of cropping and scaling. The autoaspect option tracks the filter chain and preserves my aspect ratio. so I could do this:
-sws 9 -vf crop=718:346:0:66,scale=704:336:0:1

This would produce a movie without any black bars that preserves all of the visible image at the closest possible to original resolution and also one that would play back perfectly fine on MPlayer or on my XBOX or on Videolan Player.

Granted it would look really funny if someone tried to play it on Windows Media Player




Am I on the right track or am I blathering?

[evade]

Of course I could also skip the scale and either chop a little more of the image or leave some black bars:

-vf crop=704:336:0:66

-vf crop=720:352:0:66

[unixfs]

Right track, but 346 doesn't divide by 4, so if you video is interlaced
you might have some problem.

Generally it's better to crop a little more than a little less
in order to avoid high contrast at the borders of the movie.

[evade]

Interlaced is a whole different story for sure. different scripts entirely. Most of what I encode is non-interlaced.

I will probably as a rule of thumb take the cropdetect result and round down to the nearest multiple of 16. If I it looks like I am losing too much picture I will crop and scale instead.

If you haven't tried b-frames with xvid recently you might want to give them another shot. I think they affect the picture favorably.

Thanks for your insights with the cropping.



PS
I think I have been on the commandline too much, I find myself trying to submit my post by hitting [esc] [colon] wq [enter]

[evade]

Sometimes libavcodec does a better job than XviD. Here is a script that I used for lavc encoding with hvs-best quant matrix that beat out XviD encoding Lost in Translation. Lavc produced a much cleaner picture, It smoothed some detail but produced alot less noise.



#!/bin/tcsh
# ${1}=path to vobs
# ${2}=filename
# ${3}=vf crop
cd ${1}
@ br=`cat bitrate`
echo "`date` ${2}.avi start encoding" >> encode.log
cat *.vob | mencoder -o /dev/null -ofps 23.976 -ovc lavc -lavcopts inter_matrix=18,18,18,18,19,21,23,27,18,18,18,18,19,21,24,29,18,18,19,20,22,24,28,32,18,18,20,24,27,30,35,40,19,19,22,27,33,39,46,53,21,21,24,30,39,50,61,73,23,24,28,35,46,61,79,98,27,29,32,40,53,73,98,129:intra_matrix=8,16,16,16,17,18,21,24,16,16,16,16,17,19,22,25,16,16,17,18,20,22,25,29,16,16,18,21,24,27,31,36,17,17,20,24,30,35,41,47,18,19,22,27,35,44,54,65,21,22,25,31,41,54,70,88,24,25,29,36,47,65,88,115:vpass=1:vbitrate=$br\:v4mv:vmax_b_frames=2:vhq:trell:autoaspect ${3} -aid 128 -oac copy -
echo "`date` ${2}.avi Pass 1 complete" >> encode.log
cat *.vob | mencoder -o ${2}.avi -ofps 23.976 -ovc lavc -lavcopts inter_matrix=18,18,18,18,19,21,23,27,18,18,18,18,19,21,24,29,18,18,19,20,22,24,28,32,18,18,20,24,27,30,35,40,19,19,22,27,33,39,46,53,21,21,24,30,39,50,61,73,23,24,28,35,46,61,79,98,27,29,32,40,53,73,98,129:intra_matrix=8,16,16,16,17,18,21,24,16,16,16,16,17,19,22,25,16,16,17,18,20,22,25,29,16,16,18,21,24,27,31,36,17,17,20,24,30,35,41,47,18,19,22,27,35,44,54,65,21,22,25,31,41,54,70,88,24,25,29,36,47,65,88,115:vpass=2:vbitrate=$br\:v4mv:vmax_b_frames=2:vhq:trell:autoaspect ${3} -aid 128 -oac copy -
echo "`date` ${2}.avi Finished encoding" >> encode.log

[mikeX]

Concerning XviD and VHQ:

You should really take a look at the new unofficial XviD FAQ:
http://www.vslcatena.nl/~ronald/docs/xvidfaq.html

It explains the present status of vhq.

You can also find some tests portraying the impact of various vhq settings in this thread:
Advantages of Trellis RD
(hint: look at Soulhunter's post)

I stick with at least vhq 1 (since it's now the default)
I go for 4 in extreme cases...

[evade]

Here are the hvs quant matrices in formats to be used with Mencoder and Transcode.

The option looks like this in mencoder with xvid:

quant_intra_matrix=/path/to/xvid-hvs-good.intra:quant_inter_matrix=xvid-hvs-good.inter

or like this with lavc:

-lavcopts inter_matrix=`cat /path/to/lavc-hvs-good.inter`:intra_matrix=`cat /path/to/lavc-hvs-good.intra`


Here are the files:
http://69.13.241.21/hvsquants.tar.bz2