question about subtitle colors in ifos

[E-Male]

(if this belongs into the dvd-authoring forum please move it)

my understanding of dvd-subs is this:
in the sup are the pictures which contain 4 s tandart colors
and in the ifo these 4 get mapped to one color and transparency each

but now i wonder how the hearing-impared-subs are done that show the subs in a different color for every character

thx for any help

[movax]

I believe using IFOEdit, you can change the sub colors to your liking. I've never seen a DVD with the unique color per character though...either some kind of trick, or a clumsy concatenating subtitles of different colors.

[Matthew]

I don't see how the subtitles could have a different coloured character within each subpicture either :confused:

As I understand it, the way it works is this...

Each PGC contains a palette of 16 colours (0-15), which can be changed in IFOEdit. They are stored in YUV.

Each subpicture in the VOBs references 4 of these colours in the IFO.
So one subpicture may reference 4, 7, 11, 2
Another may reference 0, 4, 7, 1
Hence the 2 subpictures will display with different colours.
They can be part of the same subtitle stream, i.e. colours can switch (although it is uncommon)

Each subpicture in the VOBs also stores a transparency value of 0->15. The background is 0 and the other 3 are often 15,15,15. So transparencies can change within a subtitle stream too, although again it is uncommon.

[windtrader]

It is also possible that the subs are not a true sub stream and are encoded into the video stream. They could then make the subs look like anything. If you have the DVD, turn on/off the various subs if they are listed. If they don't exist and you see the subs, then they are part the video.

[Abond]

Different color for each actor (character playing, role), not for each letter

[windtrader]

If the DVD's IFO is used to set colors then they remain constant throughout the PGC (title). = EDITED: see end = At a lower level, there are indicators embedded within the streams. It might be possible to specify subtitle color settings at the frame level. Maybe this is how forced subs are implemented. Then again forced subs may just be a discrete subtitle stream that is switched on/off.

I can not see it possible at all to have parts of a given subtitle text shown in different colors, as in different actors speaking. If it possible to set colors at the frame level then one could edit the sub text file, break out the various dialog for each character and code the colors. If possible it would be a hella work.

An alternative would be to just prefix the text with a character icon. I've seen hearing impared subs use [character name] already.

EDIT: I found this reference that helps clear up where subtitle color is controlled.
http://forum.doom9.org/showthread.php?p=694285#post694285

Came across some other info that suggests that the subtitle attributes can be set differently for each subtitile.

[E-Male]

Each PGC contains a palette of 16 colours (0-15), which can be changed in IFOEdit. They are stored in YUV.

so there are 16 colors in total and 4 can be used at the same time

thx, that answers my question

[Paddington]

In the following link, http://dvd.sourceforge.net/dvdinfo/spu.html, you can find out the exact specification. As you can see from here, command 0x07 allows to define separate areas inside one subtitle, where you can have different values for colors and transparency, so theoretically you could use more than 4 colors in one subtitle - I don't know any program that allows you to use this feature though...

[windtrader]

@Paddy - Ouchee! Trying to set different colors to text in a given frame would be a tad difficult. At this point if anyone was going to need to do this I would just tell them to rip the existing subs out into graphic files and use a simple graphic tool to color and move the text around then just mux the graphic files back in. At least I can explain to someone how to do it.

I'm sure you can explain how one is to fiddle with the 07 command in the subpic headers :-))