How to change the DAR of a VOB?

[ukb007]

Forgive me for asking what may be common knowledge here:

1. Is the DAR information of a VOB put in the .ifo file?
2. Can IfoEdit actually edit the .ifo file?

I apologise if these questions are non-issues here.

Regards.

[2COOL]

Originally posted by ukb007
1. Is the DAR information of a VOB put in the .ifo file? It's set in the IFO and VOBs
2. Can IfoEdit actually edit the .ifo file? C'mon now. IFO...edit...Of course, IfoEedit can do it! It wouldn't be called that, wouldn't it?

[ukb007]

Thanks very much.

Okay, then. One can edit the DAR setup in the .ifo file. How d'you go about editing the DAR tag in the VOB itself?

Regards.

[2COOL]

You can manually do it with VobEdit and it's going to take an eternity when you have hundreds of Video Packs. I'm not a vStrip expert but I believe you can do it with that. There's this CLI switch in it's help file.

-aQ changes the aspect-ratio to Q.

Sorry! I can't help you too much as I haven't been in your situation. Why the need to change it?

[ukb007]

Incidentally, you have the most colorful posts in this forum.

Quote:
----------------------------------
Why the need to change it?
----------------------------------

Okay. Here's this problem I have (I quote from another post elsewhere (http://forum.doom9.org/showthread.php?s=&postid=570004#post570004)):

I have recently received a DVD of a concert in which the menu page points at different participants' performances. When I play it in PowerDVD with 'Keep Aspect Ratio' checked, the menu page appears sqashed from the sides (as 4:3) with the faces tall; when the real VOBs are called in by the menu items they are also squashed, all of them. I have to manually stretch them after unchecking 'Keep Aspect Ratio'.

Now when I play the VOBs separately and directly in PowerDVD with 'Keep Aspect Ratio' checked, the VOBS, all of them, play beautifully in their right AR (widescreen).

Obviously the authoring was in error. It seems that the VOBs themselves have the DAR tag correct (16:9), but the menu page has it wrong (4:3) which is carried over (?) to the VOBs when accessed from the menu. At least that's what looks like the explanation to me. All I want is to be able to play the concert in correct AR from the menu.

At this point, I find I'll have to re-author the DVD. It was a concert in which my son participated. That's the reason I was asking those questions.

Thanks again for your help, and regards.

[2COOL]

So if the VOBs play great separately in PowerDVD then it's logical to assume that you have an error in your IFO. Is your video attribute in your IFO say 16:9?

[ukb007]

The ifo file, opened in IfoEdit, says:

---------------------------------------------------------------------
VTS overview:

Menu attributes:
Video: MPEG-2 720x480 (NTSC) (NTSC 520/60) (4:3) (not specified perm. display)
SubPicture 1: Not specified (2-bit rle)

Title set (Movie) attributes:
Video: MPEG-2 720x480 (NTSC) (NTSC 520/60) (4:3) (not specified perm. display)
---------------------------------------------------------------------

...etc.

Maybe this instruction of the 'movie' attributes (4:3) is confusing PowerDVD while attempting to play off the .ifo, and it is then disregarding the DAR tag in the VOBs themselves, playing them at 4:3 as directed by the .ifo instead of 16:9 that must be present in the individual VOBs.

Thank you, 2COOL. Regards.

[2COOL]

No problemo...just play your demo! :p

[jsoto]

Aspect Ratio, resolution, and other video attributes are in MPEG video stream, not in VOB pack headers. Not easy to modify them in VobEdit, even in a single pack.

dvdpatcher is able to do what you want, in mpeg files or directly in the VOB. Look for it in doom9's download section.

BTW, I've seen some SW that do not use the IFO data, but the MPEG one.

jsoto

[mpucoder]

Well, the players are supposed to ignore the MPEG data and obey the ifo data. It's easy enough to change, double click on the line that displays the movie video attributes. Change to 16:9, click OK, and then SAVE the ifo.

[jsoto]

Yep, my previous post is a little bit confusing.

What I'm saying is how to change the DAR inside the VOB, but, as mpucoder says, players should follow IFO indications.

DAR is easy to change, (even inside the VOB with dvdpatcher), so the best option is to keep coherent VOB and IFO, both with the right info. In ukb007's case, he has to change only the IFO, because the VOB seems to have the right info.

About SW using MPEG DAR data, I was thinking in DVD2SVCD. IIRC, it takes the DAR from the MPEG, not from the IFO.

jsoto

[ukb007]

Your posts nicely complement the training I've received from 2COOL.

jsoto: you mention sw using mpeg DAR info rather than ifo; you have any software players in mind that do that?

Regards.

[jsoto]

Originally posted by ukb007
jsoto: you mention sw using mpeg DAR info rather than ifo; you have any software players in mind that do that?
No, I do not know a SW player with this behavior. (Unless you open directly the VOB, as you said).
jsoto

[ukb007]

Of course, as mpucoder has said, all software players are supposed to ignore the MPEG data and obey the ifo data as a general rule. So I guess some players may offer an exception to that rule as an optional control, [e.g., bsplayer or zoomplayer], and others are rigid and don't[e.g., wmplayer].

Regards.

[ukb007]

DVDPatcher seems indeed to be a nifty utility. Its Readme.txt, however, is in German. It seems to be able to alter 5 attributes of supported video files:

1. Bitrate [3.5/8.0/15.0/Custom]
2. Horizontal Size in Pixels [352/480/528/544/704/720/Custom]
3. Vertical Size [x576 (PAL)/x480 (NTSC)/Custom]
4. Framerate [23.97 (NTSC FILM)/25 (PAL)/29.97 (NTSC)]
5. Aspect Ratio [4:3/16:9]

When it opens a supported file, DVDPatcher displays its attributes in a window. Apparently it does not provide a scope to choose among those attributes; it works on all of them. So for those ones that I want to keep unchanged, I make sure to keep current and target values the same.

For the final 'Patch' command, there are two choises:

1. Patch First header only
2. Patch Entire file.

Of course, an expert would know the situations where one would choose one over the other, but I don't; what are they?

And there's this in the Readme file:

Jeder der schonmal versucht hat, aus einem aufgenommenen DVB- MPEG2 File eine DVD oder MiniDVD zu erstellen, kennt sicherlich das Problem:

Fast alle DVD Authoringprogramme meckern entweder, die nicht DVD- konforme, hohe DVB- Bitrate (15MBit) oder die falsche Auflösung an. Da die von den Sendern eingetragene Bitrate eher ein theoretischer Wert ist, kann man diese problemlos auf einen kleineren Wert umpatchen. Genau hierfür hab ich das kleien Tool DVDPatcher geschrieben. Nebenbei kann dieses noch die eingetragene Auflösung und das Seitenverhältnis (4:3 oder 16:9) umpatchen. Einfach das MPEG File (*.mpg, *.m2v, *.vob...) via drag and drop auf die Programmoberfläche ziehen, die Paramter einstellen und auf "Patch now!" klicken. Nach der Erstellung des DVD- Inhaltes sollte das *.vob File wieder auf die Originalwerte zurückgepatcht werden, damit der DVD Player die richtigen Informationen bekommt und den Film korrekt wiedergeben kann.

If it isn't asking too much, can I please be favored with an English or a French translation of this passage?

Regards.

[jsoto]

Sorry, I do not speak German, but I can explain you the meaning of the parameters:

1. Bitrate [3.5/8.0/15.0/Custom]:
Bitrate of the stream. Not sure how it affects in the decoding process. Used in the authoring (muxing) process.
2. Horizontal Size in Pixels [352/480/528/544/704/720/Custom]
3. Vertical Size [x576 (PAL)/x480 (NTSC)/Custom]
Horiz and Vertical resolution. DVDpatcher changes the header/s, but obviously, the MPEG video-stream should be coherent with the header, if not, the decoding process will fail.
4. Framerate [23.97 (NTSC FILM)/25 (PAL)/29.97 (NTSC)]
Frame rate of the video-stream. Again, it should be coherent with the MPEG-video-stream.
5. Aspect Ratio [4:3/16:9]
This parameter indicates the Display Aspect Ratio. The decoding process is not affected, so you can safely change it.

So, the only parameter you can change in a definitive way is the DAR. The rest of the changes should be temporary. I. e., imaging you are trying to to use an authoring SW which checks the different parameters to be DVD compliant, and you are using SVCD resolution. You can "hack" the headers to a DVD resolution, use the SW to author, but after the authoring, you must recover the original parameter values.

First header/complete file: This is an option to save time. In the previous example, if the "authoring SW" checks the first header, you will save much time hacking only the first one. But for definitive modifications in DAR, I recommend to change the complete file.

jsoto

[ukb007]

I'll use DVDPatcher.

Regards.