I wanna talk about AC3 Interleaving

[cornetet]

Hi manono..

Can you point me to a good reading exercise that explains what a frame is, what a preload is, how to calculate the two, etc, etc.?? I've read the Sticky on AC3 q&a but it doesnt cover the basics. It seems like the area I'm weakest at is this AC3 area...

Like in Gknot, under the Bitrate tab, under the Interleaving & AVIOverhead section, if I tick '1x AC3' I'm presented with choosing 1-10 Frames. I dont know what a 'frame' is and why I'm choosing different frame numbers.

Also, I've noticed right underneath the Frame DropDown box is a KB box. Whenever I choose a different frame (1-10), this KB box changes numbers. Is the value in this KB box important to me? Do I need to do calculations over that number? Can it tell me something?

[manono]

Hi-

I just follow the advice of my betters. I don't know this stuff either. However, if you use 96/96, then you'd change the frames to 3, since 32ms=1 frame for AC3. Then GKnot adjusts itself automatically. Since we're talking about minute changes in overhead size (single digit KB), then it doesn't really make much difference whether or not you change that frame figure.

[Zhnujm]

i thought "frames" means video frames, not AC3 frames ?

[manono]

Hi Zhnujm-

I looked at that box in GKnot again, and when you have one frame, just below, it says interval=42ms (for 23.976fps). So, I think you're right. Thanks for bringing that up.

I guess that means that if we use AC3 audio, then we should mux it ourselves if there are ever any synch or jerky play problems (but I do that anyway).