XviD



mEncoder is a great video 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 the Xvid codec 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 the mEncoder and the XviD codec.


(Optional)
Rip vobs to Hard disk



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.



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




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



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




XviD Two Pass Encoding

Pass One




Pass Two






I will try to explain some of these options, any that I have left out below but included in the above lines are options that I am still working on/reading about
and could not explain to you adequately or accurately enough yet.




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.






INPUT

mEncoder to use the largest title on the dvd


or

mEncoder uses title one on the dvd.


you may use a file instead




CROPPING AND SCALING

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



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






BITRATE OR FINAL FILE SIZE

If a negative value is given in the bitrate option then an estimated final file size is used, if a positive value is given then bitrate is used.

Final file size, here it is 1350 MB (notice the negative value)


Bitrate to use





VIDEO FILTERS AND XVID OPTIONS

Uses the xvid codec and the xvid options follow



This controls how precise the motion estimation will be (higher is better)



This option optimizes the quantization process.



Tells mencoder the pass which pass it is on, 3 passes and higher can be used but the noticeable visual difference above 3 pass is minimal.
Some video filters and xvid options are included in the 1st pass but not used (see turbo)





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



This sets the quantizer to be used, I have used mpeg which preserves more detail at higher bitrates.
It is recommended to use h263 which is smoother at lower bitrates and I have used this on 700mb dvd rips



This option improves motion estimation by using quarter pixel precision instead of half pixel precision.
This is a cpu intensive option and is not suported by all stand alone divx players



This option improves motion estimation by looking at colour information and improved visual quality for me.



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



You can use more than 2 but I have had problems playing in stand alone divx players.



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 This adds about 30-40% to encoding time, use 1 if speed is important.


This does the same as above but on b frames



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.



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



LANGUAGE


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





AUDIO/LAME OPTIONS

Encodes the audio with the given audio codec (mp3)


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







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.




OUTPUTFILE 2nd PASS

This is the output file to use






I have added all of this into a simple shell script that automates all of this,
I have tried to leave it very simple so anyone can understand it and edit it to suit their own needs.
NOTE For compatibility with stand alone DivX players I would drop these options qpel and change max_bframes=1 and change vhq=1 and do not use gmc.




Usage

Extract script


add execute permission


run script







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.



or the 3rd title on the dvd.


or a filename







OUTPUT

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





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

or
Approx Final File Size




ASPECT RATIO

aspect ratio = enter 16/9 or 4/3





CROPPING AND SCALING

resolution = enter scaled resolution seperated by colons.




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






Sit back and wait





For a single cd rip I would start with something like,

1st pass






2nd pass







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.




noise filter (good for grainy source)



Optimize mencoder for cartoons.



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







MENCODER COMMAND LINES

Joining 2 files


Splitting a large file




Fixing broken index and interleaving



Watch movie in ascii art



TESTING


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

seek to 10 minutes into the input file



seek to 120 seconds into the input file




seek to 100mb into the film






end after 10 minutes



end after 120 seconds



end after 100 MB







Verbose output






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.


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

good work, thanks

Finished Xvid and uploaded basic script.

Good job - you've reminded me how complicated mencoder is ;)

thanks newartriot.


Added some more Random mencoder stuff to the end
Will write perl script soon covering more options (interlaced, ntsc, animation)

Oraite, n1 scripting :) thanks... rate=1200 for xvid... and about xvid asd? rate=480 ? 2lame=56 ?

Hi thanks but I don't really understand your question

asd is a polish release group doing low bitrate rips, I am guessing you are talking about them?

you will have more luck specifying a filesize option in video bitrate rather than giving an actual bitrate but for the audio bitrate try 48

let me know how you get on

Hiya syn-ack,

Great write up, for a bit of a hard core encoder. I love mEncoder and Mplayer BTW! Wiki and I spent hours together until finally reaching saturation... plus my business picked up, thank GOSH!

I haven't dabbled with encoding for several months, but if memory serves me correct, I've a question for you.

Re: Bitrate- As you well know, the length of the movie, plays a role in the final file size. I may have missed where you take this into consideration when setting the bitrate. I'm all about quality encoding, which is why I guess you're using the 1350mb figure.

I guess my questions are, How do you come to the choice of setting to 1350? Do you use that same number, regardless of the length of the movie?

Just as all the other flags (settings/options) you can set for mEncoder to do it's magic, bitrate is key also.

Hi I have set the final file size not bitrate (bitrate=-1350000)

is just an example and it is always best to calculate the bitrate based on length.

Peace :)

Love the write up and the script. Unfortunately this does not produce a PS3 compatible movie for me. It plays just fine on my PC. From what I can find it appears that the PS3 needs it to be DivX3 compliant. Any way to modify the options in the script to make movies playable on PS3?

Thanks!