Darkside_RG > Mencoder Dvd To Divx

Darkside_RG > Technical Discussions > Guides/How To > Video

syn-ack

Oct 17 2007, 11:04 PM

DIVX/LAVC

mEncoder is a multipurpose encoding tool that comes with mplayer.

I have been playing about with mEncoder and have some options I am reasonably happy with.

I have been experimenting with both lvac and mEncoder.

These options are for a high quality DVD rip, which will fit on 2 cds.
Below are the steps I have taken to rip a dvd and encode it using mEncoder and the XviD codec.

(Optional)
Rip vobs to Hard disk

CODE

mplayer dvd:// -dumpstream -dumpfile dvd.vob

CROPPING

Run mplayer with the cropdetect option this gives us the values needed for cropping the movie.
The command below will seek to 360 seconds into the film and stop after 15 seconds so we are seeing the crop values for the movie.

CODE

mplayer dvd:// -vf cropdetect -ss 360 -endpos 15

A list of crop values for the movie are printed to the terminal so we can then pass to mEncoder.

EXAMPLE

CODE

[CROP] Crop area: X: 4..714  Y:  74..508 (-vf crop=704:432:8:76).0
[CROP] Crop area: X: 4..714  Y:  74..508 (-vf crop=704:432:8:76).0
[CROP] Crop area: X: 4..714  Y:  74..508 (-vf crop=704:432:8:76).0
[CROP] Crop area: X: 4..714  Y:  74..508 (-vf crop=704:432:8:76).0

The important values are the *:*:*:* values in brackets

EXAMPLE

CODE

704:432:8:76

These will change per dvd so you need to run this with every dvd.
Make a note of these values.

2 PASS LAVC

1ST PASS

CODE

mencoder -v "$input" -vf crop="$crop",scale="$scale" -ffourcc DX50 -ovc lavc -lavcopts \ vcodec=mpeg4:trell:psnr:vhq:mbd=2:qpel:v4mv:vlelim=-2:vcelim=-5:vpass=1:vbitrate="$bitrate":autoaspect \
-force-avi-aspect "$aspect" -alang en -ofps 25 -fps 25 -oac mp3lame -lameopts abr:br=128:vol=9 -o /dev/null

2ND PASS

CODE

mencoder -v "$input" -vf crop="$crop",scale="$scale" -ffourcc DX50 -ovc lavc -lavcopts \ vcodec=mpeg4:trell:psnr:vhq:mbd=2:qpel:v4mv:vlelim=-2:vcelim=-5:vpass=2:vbitrate="$bitrate":autoaspect \
-force-avi-aspect "$aspect" -alang en -ofps 25 -fps 25 -oac mp3lame -lameopts abr:br=128:vol=9 -o "$output"

lsdvd is a nice little tool to list the contents of a dvd from the command line. It will be in most linux/unix repositories.

CODE

lsdvd

INPUT

mEncoder to use the largest title on the dvd

CODE

dvd://

or

mEncoder uses title one on the dvd.

CODE

dvd://1

you may use a file instead

CODE

movie.mpg

CROPPING AND SCALING

This is our crop values taken from the cropdetect output above.

CODE

crop=704:432:8:76

This is the resolution, I scale to around 704:304 for 16/9 or 640x480 for 4/3

CODE

scale=704:304

I have use -sws 2 bicubic, can be better at lower bitrates. I have experimented with lanczos scaling (can be sharper) but am not as happy as I am with the bicubic.
(I expect my options just need tweaking)

CODE

-sws 2

MAINTAINING COMPATIBILITY

This sets our header to DIVX5 and not the default FMP4,
lavc is not compatible with divx4 so we use DX50 for avi header so it can be played under windows players (not vlc)using more exotic options(b-frames, qpel etc)

CODE

-ffourcc=DX50

LAVC OPTIONS

This tells mEncoder to use lavc and the options follow (seperated by a colon)

CODE

-ovc lavc -lavcopts

uses the mpeg4 codec

CODE

vcodec=mpeg4

Optimizes quantization process

CODE

trell

Print the PSNR (peak signal to noise ratio) for the whole video after encoding.

CODE

psnr

From the man page
"vhq tries to find a motion vector that minimizes the difference between the reference frame and the encoded frame
With this setting activated, Xvid will also use the frequency domain (DCT) to search for a motion vector that minimizes not only the spatial difference but also the encoding length of the block"
Clever searching to me :wink and recomeded in all documents I have read.

CODE

vhq

This encodes each macroblock multiple ways and chooses the best one, it improved visual quality noticeably and added to encoded time
(mbd=1 is the same as vhq)

CODE

mbd=2

Use four motion vectors per macroblock also increases quality, selects more precise motion estimation and works well with mbd.

CODE

v4mv

These options deal with heurstics when encoding blocks (recomended for live movies, remove for animation.)
Other possible recomended values to try are -3 -6 and -4 and 9

CODE

vlelim=-2

CODE

vcelim=-5

This option disables some of the more cpu hungry options on the first pass, speeding things up a bit.

CODE

turbo

Tells mencoder the pass which pass it is working on, 3 passes and higher can be used but the noticeable quality difference above 3 pass is minimal.

CODE

vpass=1

CODE

vpass=2

BITRATE

Bitrate to be used

CODE

vbitrate=1250

ASPECT

This preserves the aspect of the dvd and writes the information to the header, only mplayer takes any notice of this.
To have windows media player,vlc or xine play our movie at the correct aspect ratio we need to scale (as above) to an appropriate 16/9 or 4/3 resolution.

CODE

autoaspect

To force a specific aspect and can be used with -ovc copy to change aspect.

CODE

force-avi-aspect 16/9

LANGUAGE AND AUDIO

This option specifies the language code to use for the audio (english) otherwise we may end up with the directors commentary.

CODE

-alang en

Encodes the audio with the given audio codec (mp3)

CODE

-oac mp3lame -lameopts

Use an average bitrate of 128 for the audio track and boosts the volume.

CODE

abr:br=128:vol=9

OUTPUTFILE 1st PASS

This sends the output of the first pass to /dev/null A file (divx2pass.log) is created on the first pass containing information
about the input video file (movements colour information etc), this is read on the 2nd pass.

CODE

-o /dev/null

OUTPUTFILE 2nd PASS

This is the output file to use

CODE

-o Finished_Movie.avi

SCRIPT

Usage

Extract script

CODE

gzip -d dvd2xvid.gz

add execute permission

CODE

chmod +x dvd2xvid

run script

CODE

./dvd2xvid

You will be asked a set of questions

INPUT

input device = enter the file or device to use as input

For the largest title on the dvd.

CODE

dvd://

or the 3rd title on the dvd.

CODE

dvd://3

or a filename

CODE

/home/synack/movies/movie.vob

CODE

/home/synack/movies/movie.mpg

OUTPUT

output file = enter the desired output filename without an extension.

CODE

New_Movie.

BITRATE OR FINAL FILE SIZE

bitrate or final filesize = as explained above, using a negative value specifies an approximate file size.
adding a positive value uses the specified bitrate
Bitrate

CODE

1200

or
Approx Final File Size

CODE

-1250000

ASPECT RATIO

aspect ratio = enter 16/9 or 4/3

CODE

16/9

CROPPING AND SCALING

resolution = enter scaled resolution seperated by colons.

CODE

704:304

cropdetect will now be run, enter the values in the brackets seperated by colons.

CODE

688:432:18:68

Sit back and wait

RANDOM MENCODER STUFF

OTHER VIDEO FILTERS

Deinterlace

for interlaced content,
I have used the -kerndeint and -lavcdeint on a dvb-t source and have found lavcdeint option a lot smoother.

CODE

-kerndeint
-lavcdeint
-pp=lb

noise filter (good for grainy source)

CODE

hqdn3d=2:1:2.

Optimize mencoder for cartoons.

CODE

cartoon

Global Motion Compensation for help with movies with lots of panning, zooming and rotating images.

CODE

gmc

MENCODER COMMAND LINES

Joining 2 files

CODE

mencoder -ovc copy -oac copy -o Joinedfilm.avi filmCD1.avi filmCD2.avi

Splitting a large file

CODE

mencoder large_file.avi -ss 0 -endpos 700mb -ovc copy -oac copy -o cut_file_Part1.avi

CODE

mencoder large_file.avi -ss 700mb -ovc copy -oac copy -o cut_file_Part2.avi

Fixing broken index and interleaving

CODE

mencoder -idx broken_file.avi -ovc copy -oac copy -o fixed_file.avi

Watch movie in ascii art

CODE

mplayer -vo aa:width=***:height=*** movie.avi

TESTING

These options are good for test encoding/playing part of a movie.

seek to 10 minutes into the input file

CODE

-ss 10:00

seek to 120 seconds into the input file

CODE

-ss 120

seek to 100mb into the film

CODE

-ss 100mb

end after 10 minutes

CODE

-endpos 10:00

end after 120 seconds

CODE

-endpos 120

end after 100 MB

CODE

-endpos 100mb

Verbose output

CODE

mencoder -v

CODE

mplayer -v

Another cool thing about this tool is that some of the options/switches are interchangable
for example

Will play track 1 on the dvd at a scaled resolution of 704x304, staring after 10 minutes and ending after 120 seconds.

CODE

mplayer dvd://1 -vf scale=704:304 -ss 10:00 -endpos 120

Will encode track 1 on the dvd at a scaled resolution of 704:304, staring after 10 minutes and ending after 120 seconds. (extra options needed)

CODE

mencoder dvd://1 -vf scale=704:304 -ss 10:00 -endpos 120

Have fun

syn-ack

Oct 19 2007, 11:42 PM

Changed lots of options and updated explanations (may change a few more over the next few days)
Added basic script

This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.