PAL to NTSC Menu conversion - still needs some refinement

[pipieye]

This is not a PAL to NTSC movie conversion, as the topic has been discussed so many times elsewhere.
This is a PAL to NTSC Menu conversion. I'm writing this in the hope that someone will refine it or write a program to automate the procedure.

To understand how this works, we need to know the components that make up the menu.
It's really fairly simple in a way. The way I see it, menus are made up of small movie vobs plus the addition of buttons/hotspots.

First use vobsub and demux by vobid on the vts_xx_0.vob which is where the menus are usually found. Now open one of this tiny vobs with VOBrator and notice it is composed of the following:

NAV (0xBB stream) - navigation stream (buttons/hotspots info?)
VES (0xE0 stream) - the usual mpg2 stream for moving menus, still menus is a 1 frame mpg2 stream
SPES (0x20 stream) - the subpicture stream, would be the subtitle stream if its the main movie
AES (0x80 stream) - the usual audio stream

Now we all know how to convert a PAL to NTSC main movie, so it should be no problem to convert the VES and AES stream the usual way.
For the VES with 1 frame mpg2, there is an easier way and produces higher quality I will discuss below.

So the only problem is converting the buttons/hotspots stream and the subpicture stream from PAL to NTSC.

Buttons are nothing more than a rectangle definition called hotspots by some people. To convert this, use menuedit and open the menu vob and find the cell you want. Edit/preview will show you the menu plus the hotspots.
There is a save feature that will save the buttons/hotspots into a Menu Button Layout file or MBL file. Open the resulting mbl file with notepad and edit the rect={ L T R B } sections.
To change from PAL to NTSC divide the Top and Bottom by 1.2 rounding off to nearest integer.

For the subpicture stream, subrip seems to do the trick with the save subpicture as bmp. Then convert the bmp to 720x480 with your favorite graphics program. I use ACDsee as it has a batch mode and Lancoz resize for better quality. This needs to be converted back to a sup format to be remuxed into vob.
I can't find a suitable program to do this properly. Bmp2sup anyone?

As mentioned earlier, if you have a still menu, you can also use menuedit and do a save frame. Then convert the bmp to 720x480 to get your background picture to NTSC format. This needs to be converted back to mpeg2 stream for remuxing back into a vob.

Now that all the pieces are in NTSC format, we need to mux them back into a vob file. Leave out the buttons mdl for now, and just mux the mpeg2, audio, and subpictures. Since I can't find a suitable program to do the subpicture, for now I use one of the authoring programs to do this.

With the new NTSC vob menu, we need to put this back into its original place and mux the edited buttons/hotspot mbl file.
So open the original vts_xx_0.vob using menuedit, find the cell id of the menu you want and click replace, then select the newly created vob and pick the cell, and replace.
Select the cell again and edit/preview as before, this time load the NTSC version of the mbl file and it should fit perfectly onto the NTSC background.

Use IFOedit and open your IFO file and edit all menu/movie attributes from PAL to NTSC. This should update the BUPs as well.

Lastly, run IFOedit and do a menu extra and strip. Make sure everything is checked so we are not really stripping anything. What this will do is to relink all the buttons back with the IFO file.
Don't forget to do a get vts sector as usual.

Note: The only problem I have with this procedure is the color mapping of the subpicture during the remux of the vobs using the authoring software. The result I'm getting is the buttons selection/highlight colors are changed. Sometimes it becomes transparent so you dont even see them, but it is there.
I can't figure a way to determine what was the original mapping or how to preserve the mapping. Since the subpicture are slightly different than subtitles in the way colors are mapped??

[hech54]

Too much like work for me man...
I just use a PAL/NTSC converting DVD player into my DVD Recorder. Great solution IF you already have spent the money on the recorder.