Where is written data of vertical position of DVD subtitles

[dinderi]

Hi,
I'm looking for the information, where can I find information about vertical possition of subtitles in DVD.
I try to write special routin in firmware for my dvd stand-alone player, to let me adjust vertical dvd subtitles possition. I'm not very skilled in dvd authoring, but know for sure that PC shows subtitles on different position then my dvd player. That makes me to belive, that my player changes the possition itselfs. If I know where the default position is written (In Ifo or vob or sup.) I could find the code in dvd player's firmware, that reads it and adjust. Then I can modyfie it, to let me move subs up and down, during playback.
I need your help guys, please. Otherwise I will spend a year more trying to do it
Thank you in advance.
Dinderi

[SLK001]

AFAIK, there is no vertical positioning of subtitles. A subtitle is a 720x480 bitmapped image using up to 4 colors (with one being transparent) that is overlaid on the playing video.

I don't think that there are any abilities of a player to offset the overlay. It is what it is.

[SLK001]

In your case (assuming that you are in PAL country), the bitmap image is 720x576.

[dinderi]

Yes I know it But somehow my Pioneer dvd player lower subtitles on the screen, comparing how thay are displayed, while the same movie is played on PC.
Okay, thank you very much for your answer, I'm a little step closer, to find (or not ) the solution. It means, that I need to look for code that make it, in player's firmware, only

[tinker]

They are coded in SUP part. You can get DVDSubEdit (free) to look at them and reposition them at the same time.
Sometime the difference is how they were put in, either as 4:3 or 16:9 format.
That is why dvd player will place them in different spot.

[jagabo]

Yes I know it :) But somehow my Pioneer dvd player lower subtitles on the screen, comparing how thay are displayed, while the same movie is played on PC.

Are you sure it's not just a matter of the TV's overscan vs the non-overscan of the PC? That is, the subs are in the same place but you see the the frame all the way out to the edges on the PC, whereas about five percent the frame is cut off on each side of the TV.

[olyteddy]

My Panasonic DVD player allows you to move them up or down. I can place them almost outside the image on letterboxed stuff. Power DVD allows a second set of them and puts the second at the top of the screen so I know they are moveable.

[jagabo]

Yes, but particular software or players having the ability to move the subtitles on demand doesn't mean that positioning subs is part of the DVD spec.

[olyteddy]

I realize that. My post was in response to your post about overscan and to support the OP's theory that it's his player that positions them where they are.

[SLK001]

I realize that. My post was in response to your post about overscan and to support the OP's theory that it's his player that positions them where they are.

It was my impression that the OP wanted to know where the "positioning information" was on the DVD that he wanted to modify. Players may have the ability to shift the position of the overlays (subtitles) on the screen, but AFAIK, there is no way to do this on a DVD.

As I said, a subtitle is stored on a DVD as only a 4 color bitmapped image of the text to be displayed.

[tinker]

but AFAIK, there is no way to do this on a DVD.

Try DVDSubEdit, it will modify existing file to reposition subs as you wish. Than burn new DVD.

[SLK001]

but AFAIK, there is no way to do this on a DVD.

Try DVDSubEdit, it will modify existing file to reposition subs as you wish. Than burn new DVD.

Yes, I KNOW that what the OP wants can be accomplished, but only thru manipulation of the bitmapped images. That is what DVDSubEdit does.

[olyteddy]

...I try to write special routin in firmware for my dvd stand-alone player, to let me adjust vertical dvd subtitles possition...If I know where the default position is written (In Ifo or vob or sup.) I could find the code in dvd player's firmware, that reads it and adjust. Then I can modyfie it, to let me move subs up and down, during playback...

Sry, doesn't sound to me like he's wanting to re-author his DVDs to move the subtitles...

[dinderi]

Thank you very much guys for your replies. Special, additional thanks, I send to tinker and olyteddy
olyteddy, would you please tell me, what Panasonic you have?
New Panasonic players works on MTK chip, the same as Pioneer. I can try to find that code - that moves dvd subtitles - in it's firmware and implement it into Pioneer.

No, I do not want to reauthor my dvds. I just want to reprogram my DVD player, to let me move dvd subtitles on a screen. I found Tinker's and Olyteddy's suggestions, the most usefull in this case, but any other sugestions are very welcome. As more I know from you guys, as easier would be to understand the problem, for me.

P.S. I'm sorry for my English, that may be not clear enough to understand. I learned it mostly in Australia ...
Hope, I could fly safely to Australia again, and no one would kill me, right at Melbourne's airport, since now

Happy Easter to all of you

[olyteddy]

I have a 5 disk Panasonic Home Theater Model SA-HT700. I don't know much about the firmware, last I dabbled in Machine Code was the 6502 chip in my Commodore Vic-20 or a bit of Z-80 in my Timex Sinclair...

[dinderi]

olyteddy, did you open player's case? What chip is inside? Is it MTK?

[kush]

@ The OP, I can't be of help here, but I felt compelled to reply anyway.

Do not be ashamed in your (perceived lack of) mastery of the English language in any way. You seem to have quite a decent grasp of it as is - much more so than many of my fellow Americans (we sure butchered the Queen's 'native tongue' didn't we? ). Put another way, there's no way in bloody hell I could come to Poland and even begin to know where to start re: even basic conversation (in Polish of course).

[olyteddy]

I don't know and don't care to find out what's inside, but there seems to be people who might know over at http://www.avsforum.com/avs-vb/showthread.php?t=405756

[jeanl]

Yes, I KNOW that what the OP wants can be accomplished, but only thru manipulation of the bitmapped images. That is what DVDSubEdit does.

Technically, that's not really true. You can change the vertical positioning of a subtitle without manipulating the bimap image itself. There are commands at the end of the subpic information, that determine where in the image (vertically) the top of the subtitle bitmap is to be placed. You can change the arguments of these commands to change that position. That's exactly what DVDSubEdit does.
On the other hand, it's true that you can't change the horizontal position without re-encoding the bitmap, but that's not what the original poster was asking.
A great source of info is www.mpucoder.com, but I think you have to register to get the info on the subtitle encoding, and the definitions of the commands I'm talking about.
Jeanl

[dinderi]

Thank all of you for the answers. You are very helpfull, guys

[SLK001]

Yes, I KNOW that what the OP wants can be accomplished, but only thru manipulation of the bitmapped images. That is what DVDSubEdit does.

Technically, that's not really true. You can change the vertical positioning of a subtitle without manipulating the bimap image itself. There are commands at the end of the subpic information, that determine where in the image (vertically) the top of the subtitle bitmap is to be placed. You can change the arguments of these commands to change that position. That's exactly what DVDSubEdit does.
On the other hand, it's true that you can't change the horizontal position without re-encoding the bitmap, but that's not what the original poster was asking.
A great source of info is www.mpucoder.com, but I think you have to register to get the info on the subtitle encoding, and the definitions of the commands I'm talking about.
Jeanl

jeanl, aren't you the author of this program?

[jeanl]

Yes... that's how I know what DVDSubEdit does!
But the source code is public, so if you're into reverse engineering, that's another way to go!
Jeanl

[jagabo]

You can change the vertical positioning of a subtitle without manipulating the bimap image itself. There are commands at the end of the subpic information, that determine where in the image (vertically) the top of the subtitle bitmap is to be placed. You can change the arguments of these commands to change that position.

Interesting. Good to know. Is this argument for each bitmap or is it global to all the subs? (I don't know much about subs on DVDs.)

[jeanl]

no, each subpic has a set of commands, each with their own arguments. If you're really interested, check out the mpucoder.com web site... all the info is there.
Jeanl

[dinderi]

check out the mpucoder.com web site... all the info is there.

I guess, we should make pioneerdivx.net, also "only for contribiuting members"

[jeanl]

Yeah, that's the only problem with this site .... But the info is quite thorough and really useful for programmers...
YOu can also find some info on DVD subtitles on the net, gathered by some people who did an extensive amount of reverse engineering, but it's not as complete/accurate...
Jeanl