dvdauthor, GfD - Animated menus hesitate at end of loop

[jsbullock]

I'm using GUI for DVDAuthor 1.07 to build a DVD with switched, animated menus. I've gotten the elementary video m2v and audio ac3 streams very close to the second for timing reflected in the duration setting for the GfD menu. I also loop my video/audio twice, so I know the actual looping is smooth - and the audio is well sync'd. Despite all this, animated menus turn out having such a lag or hesitation when they start or reach the end of the loop, that I actually use it in some to the effect of making the highlight masks blink by knocking down the menu duration to 1 second. I want a transparent, animated loop replaying smoothly for most of them, however. I'm not even sure how the menu duration parameter in GfD gets batched to dvdauthor. I certainly cant' find those parameters in the Author.xml file. Any advice to eliminate or minimize this gap would be greatly appreciated - j

p.s. - I'm using internal register variables and pre/post command scripts that handle first-run and subtitle default issues. At this point, I'm not recoding them just to try switching over to Muxman as the GfD engine, so don't bother suggesting it.

[guns1inger]

The DVD spec is a very simple beast. I don't believe it includes the concept of caching, so when you get to the end of the video asset (your menu) it has to go back to the beginning of the asset and load it again to start the new loop. This is what is causing your break. Look at any good commercial menu and you will see that it does the same thing. The other factor is the player. Some players seek much more slowly than others.

There are two possible "solutions" :

1. Using what you have, make your menu asset much longer - perhaps 4 loops instead of two, so there is a longer playing time between breaks.

2. DVD Lab Pro supports the concept of cells. These are like chapter points in a menu, and are very good for motion menus where there is a video intro, then the menu, and the menu needs to loop. The reason they are better than the standard approach is that you never actually leave the asset, so you can loop to the beginning much more quickly.

[borax]

That's exactly the approach which is used here too. The loop is done with the command: jump cell 1;
But I don't know how well or bad dvdauthor handles this command...

...how the menu duration parameter in GfD gets batched to dvdauthor...

Not at all. This duration parameter is just used 'internally' for the avisynth script. On the DVD (or the menu-vob file respectively) the video (the cell with the menu) is shown until it ends and then restarted.
So the best way to get something like a smooth loop is to start/end it with 'fading'. Then the actual unavoidable break is not that disturbing. This is also done by most commercial DVDs.