Pyther's Intraworld

I was asked to convert some European (PAL) dvds to the American (NTSC) format. With the help of a few linux tools, the process is pretty painless. A cautionary note: the process takes about 3 hours for one dvd using  my AMD X2 7750.

What you need:

• vobcopy or dvdrip
• projectx
• avidemux
• mplex (part of mjpegtools)
• wine
• dgpulldown.exe (windows app)
• dvdauthor
• dvdxchap (part of ogmtools)

First, we need to rip the DVD to the computer. We can do this by using dvdrip or vobcopy. Vobcoby is a simple command line utility that rips vob files straight from the dvd to the hard drive. dvdrip is a gui tool which is very easy to use. Load it up, create a new project, select the rip tab, and pick the title you want to rip. Ripping the dvd will probably take anywhere from 15-20 minutes.

Vobcopy Example: cd /home/pyther/dvdrip and vobcopy /dev/sr0

Next, we want demux (seperate) the audio and the video. ProjectX is very easy to use for this task and ProjectX insures the video and audio stay in sync.

To Demux the video:

• Start projectx
• File->Add
• Select all the vob files that were just created
• At the bottom where it says “recent output directories” select “output to same location as 1st file in collection”
• Then click the Quick Start button on the side

This result in the following files being created:

• *.m2v = mpeg 2 video file
• *.ac3 = AC3 Audio File
• *.sub = Subtitle Files

If there are multiple audio tracks you will see zorro-001.ac3, zorro-001[1].ac3, zorro-001[2].ac3
In my case:

• zorro-001.ac3 == Hungarian
• zorro-001[1].ac3 == English
• zorro-oo1[2].ac3 == Directors Comments

Lets clean up the directory right now:

• move *.vob files into a new folder called vob
• move *.sub into a new folder called subs
• Rename the audio files (ex. zorro-001.ac3 -> hu.ac3)
• Remove any audio tracks that you do not want in your remastered dvd (ex. Directors Comments)

There are two main differences between PAL and NTSC. First, PAL plays at 25fps whereas NTSC plays at 29.97fps. Secondly, PAL uses a resolution of 720×576, but NTSC uses a resolution of 720×480. We won’t worry about the fps right now. We will concern ourselves with resizing the PAL video to 720×480. This can be done using the filters available in avidemux. With my videos I  was simply able to crop the black borders of the video. However if there is no black borders in the video, you can crop the actual movie or you could resize the movie to something smaller than 720×480.  After resizing you can then add black borders to get the video back to 720×480. I don’t know an easy way to do this, you will just have to play with the filters until you get a resolution of 720×480.

To extract the video:

• Start avidemux_qt or avidemux_gtk depending on the toolkit you want to use
• File-> Open (select the m2v file)
• Allow avidemux to index the mpg file
• Select DVD (lavc) for the video codec (on the sidebar)
• Click the filter button and add appropriate filters so the resulting resolution is 720×480.
• Click the configure button
• Select Two Pass File Size
• Enter the target size of the file (see below)

A blank dvd can hold approximately 4300MB. Therefore we need to calculate how much space our audio files take up.

In my case:

tux:zorro $ du -hs *.ac3
420M	English.ac3
420M	Hungrian.ac3

The total size of the audio is 840MB. 4300MB – 840MB = 3460MB. I would leave about a 10-20MB gap incase the file is a bit bigger than the target size. Therefore the target size you would enter would be 3440.

Now you just need to find something to do for about 2 hours. The time it takes to encode the file will greatly depend on the speed of your processor.

After the file is done encoding we need to convert it from 25fps to 29.97fps. This is done by applying a pulldown to the file. I do not quite understand this concept. For more information read this: http://neuron2.net/dgpulldown/dgpulldown.html.

Steps to convert video:

• wine dgpulldown.exe
• Select the source video (the file you just encoded using avidemux)
• Select the destination file (I would suggests naming the file source_name.pulldown.m2v)
• Select 25fps -> 29.97fps
• Click Convert

Next we need to multiplex the audio and video together.
Use mplex to do this: mplex -f 8 -o output.mpg video.m2v english.ac3 hungarian.ac3

Lastly, we need convert the mpg2 file to a dvd structure. Below is a simple config that will cause the video to play right away, with the languages defined, and chapters set.

<dvdauthor dest="./dvd">
 <vmgm></vmgm>
   <titleset>
     <titles>
       <audio lang="hu" />
       <audio lang="en" />
       <pgc>
           <vob file="/home/pyther/Patriot/Patriot.mpg"  chapters="00:00:00.000,00:10:37.760,
           00:17:18.920,00:21:38.160,00:25:02.920,00:29:05.720,00:35:16.960,00:46:57.760,
           00:49:59.560,00:53:24.360,00:55:17.680,00:59:41.880,01:03:37.160,01:04:51.480,
           01:10:23.800,01:16:28.280,01:19:36.040,01:24:29.040,01:28:44.160,01:34:06.760,
           01:46:24.560,01:53:05.120,01:54:57.720,01:59:47.000,02:15:24.520,02:22:35.840,
           02:26:53.680,02:29:46.160" />
       </pgc>
     </titles>
   </titleset>
</dvdauthor>

Save the file as dvd.xml in your working directory. Of course you will want to change the chapters and languages accordingly.

To get the chapter times from the source dvd you can run the following:

dvdxchap /dev/sr0 > chapters.txt
cat chapters.txt | cut -d'=' -f2 | sed -n 'p;N' | tr '\n' ',' | sed 's/\(.*\)./\1/'

Then you want to create a dvd directory: mkdir dvd
And now to create the dvd structure: dvdauthor -x dvd.xml

Finally, burn the contents of the dvd directory to a dvd and enjoy the movie!