[mythtv-users] What major features are planned for 0.27?

Richard peper03 at yahoo.com
Tue Nov 20 09:34:43 UTC 2012

On 20/11/12 00:55, Neil Salstrom wrote:
> Now that you mention it, I did see that addition and updated my system
> for that.  For disks that play but had stuttering, A Christmas Story
> was the worse (at the Warner Brother's logo at the beginning).  The
> patch seemed to smooth that out a bit but it did stutter briefly just
> before going to the main menu.

My patch should fix stuttering *in* menus so unless a menu is not being 
recognised as such, playback should be smooth.  Playback of video 
sequences going into or coming out of menus is not likely to be affected 
by my patch so if that's not smooth, it is almost certainly something else.

> I agree that the issues we see probably are due to either poorly
> mastered DVD's (as I believe are the case in the workout DVD's my wife
> has) or due to the attempts at out of standard errors to aggravate the
> consumer (I mean protect the content from ever being pirated).

I don't claim to know all the ins and outs of DVD authoring or what 
measures are taken by the publishers to try to prevent copying but I 
think a big part of the problem is that DVDs can (and almost always do) 
contain code that is used to determine what to play, where to jump to 
etc.  For example, some DVDs start by asking the user to select a 
language before starting the main menu.  The language selected is then 
stored internally as an arbitrary value and referenced later to decide 
which menu to show.

Some people don't want to see a menu when they play their DVD.  They 
just want the player to jump to the main feature.  If the DVD wasn't 
authored that way but the player software does it anyway, it's quite 
possible that it misses some of the setup 'code' on the DVD that is used 
later during playback.

How all of this manifests itself depends greatly on each individual DVD. 
  Some make minimal use of these features, others rely heavily on it.

At the moment, I don't think that we are stepping through the DVD 
structure as cleanly as we could.  There is at least one bit of code 
that stops one DVD I have working correctly.  But if I 'fix' that, 
another DVD that played fine before no longer plays as cleanly.  Things 
like that usually indicate that something, somewhere is taking 
shortcuts.  There are probably reasons for this but working out what was 
done intentionally and what is accidental is not at all easy!

It's also not as simple as saying "It plays fine in XYZ, take their 
implementation".  If it comes down to a few lines of code, it may be 
possible.  But other players have, in general, a different architecture 
that can't just be transplanted into Myth.  It's certainly worth 
comparing players and maybe looking at why something works there but not 
in Myth but that also means learning how those programs work internally, 
which takes even more time.

> At any rate Richard, thanks for the patch and your help!  Maybe you
> should be come an Official MythTV Dev =)

:)  I don't think that's likely to happen any time soon.  I've only just 
started looking at the code so the chance of me screwing something up 
because I didn't understand some side-effects are too great (to name 
just one reason).  I also don't know how much time I'll be able to/want 
to dedicate to it.  It's great to be able to fix problems as you find 
them but even a one-line patch can be the result of many hours work (and 
a wife who's only got some vague recollection of having seen you before!)


More information about the mythtv-users mailing list