[mythtv-users] Transcode entire DVD (menus, etc) to MPEG4?

[James L. Paul]

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On Monday 08 March 2004 10:39 pm, Scott Nicholson wrote:
> > I'm curious what player you use on your myth box to play the DVD games
> > and similar fancy features on the kid's DVDs. I've had terrible
> > compatibility problems with most non-simple menu DVDs and Xine. It's good
> > at basic menu structures most of the time, but doesn't handle everything
> > my hardware player
> > can.
>
> ... I don't even have my Myth box built yet -- I'm thinking future
> functionality here.
>
> I haven't looked too much into it, but I'm surprised to hear that Xine
> doesn't do well with DVD games and the like. I expected that it was fairly
> well advanced (but then, I haven't ever tried such DVDs on a Windows
> software player either -- maybe they're not any better?)

DVD compliancy is still young on Linux, unfortunately. Players and authoring 
tools are much more mature on other OS platforms.

> At the moment, the kids just use our $35 KOSS DVD Player.
>
> > In general, no. The menus, languages, subtitles, games, etc. are all
> > built and contained specifically in the structure of the DVD. That
> > structure does not support DivX, XVid or MPEG4. You can extract and
> > transcode elements from a DVD structure, but to keep all the features you
> > ware asking for basically requires you to keep the entire DVD structure
> > for your intended purposes.
>
> I realize that the menu structure and footage would need to be ripped as
> well.

Ripping them is one thing, re-assembling them to operate as intended with 
another format is another. Especially when there is no other format that 
duplicates DVD functionality readily at hand.

> This seems like such an obviously cool thing that I'm surprised nobody has
> put together something like this. I'm not a programmer (I know my way
> around PHP, but I have very little practical C/C++ experience) but it seems
> like it shouldn't be too hard to add this sort of functionality to an MPEG4
> player...

It's non-trivial to add to any player, apparently. Most players are unable to 
support DVD menu structures. The library that does it on Linux is still 
maturing toward full compliancy. I have a few DVDs with special features that 
don't fully work even with the most mature Windows-based players. I suspect 
most people just want the menus to work well enough to navigate to play the 
movies and few people try to use the more complex disks with software 
players.

> The DVD format is well documented, right? So it would just be a matter of
> transcoding the video files, copying the menu structures, then implementing
> the menus by calling the transcoded MPEG4 files instead of the .VOB mpeg2
> footage...

Well documented somewhat recently for wide distribution, as I understand it. 
Regardless, if you researched the format you might see why it's non-trivial 
to duplicate the features you are asking for. For example, the transcoded 
MPEG4 would presumably need to be _in_ the .VOB container multiplexed with 
all the other content. This would require a tool that could _do_ that, and we 
don't even have a Linux tool yet that fully supports MPEG2, let alone MPEG4.

The opensource development community is slowly working toward having complete 
DVD authoring tools, but we aren't there yet by a long shot compared with the 
proprietary closedsource offerings. I doubt we'll see the type of features 
you are looking for until after we have tools that fully support the existing 
standards.

> > Not that I'm aware of. Although, in my experience, I can usually shrink a
> > DVD about 50% without significant image degradation. My needs are
> > different from yours though. I rip my DVDs to my server storage, but only
> > the movie itself.
> > If I want to use the special features, I'm willing to pop the DVD into
> > the player. :)
>
> Sounds like maybe that's what I'll have to do, too... either that or pony
> up for a handful of hard drives.

I suspect so. IMHO, the cost of the storage space would be cheaper, faster, 
and easier than creating the type of solution you want. If you have enough 
space now for MPEG4 sizes, you should only need to double it at worst, since 
an acceptable MPEG2 version of the content should be only about twice the 
size of a good MPEG4.

> Maybe I can find enough MAME and SNES games to keep the kids busy, and
> they'll forget all about the DVD ones.

Perhaps just the 3 or 4 most popular DVD ones would be good enough then? :)

> Thanks for the feedback!
> Scott
>
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