Encoding for Motion Menu Background

farss wrote on 3/9/2004, 1:39 PM
I'm creating a motion menu background for a DVDA project. As I understand it DVDA has to encode this within DVDA as it needs to overlay the buttons and text etc.
If my assumption is correct then there's no advantage to encoding the AVI to mpeg/ac3 from the Vegas TL as DVDA is going to re-encode it anyway, I might as well just point DVDA to the rendered AVI and let it do it's thing. Problem I have with this approach is I don't get any control over the encoding other than bitrate. I suppose I could encode the audio to ac3 as DVDA would have no reason to change that.

The core of my issue is that the background need to run as a 35 minute loop and to fit into the 1 GB limit that ends up at a pretty low bitrate so I'm going to need as much optimisation as possible.

Comments

mark2929 wrote on 3/9/2004, 2:10 PM
I think what your looking for farrs is a way to have more control so perhaps the professional standalone mainconcept encoder perhaps frameserving out of vegas may give you the tools you need ? Perhaps?
corug7 wrote on 3/9/2004, 2:24 PM
farss,
I could be wrong, but I think DVDA will re-encode mp3 files, but not ac3. If you import the mpeg2 video and ac3 audio tracks seperately, the DVDA encoder shouldn't need to demux them.
farss wrote on 3/9/2004, 3:12 PM
Normally this is correct, however for the menu backgrounds somehow the buttons and text have to appear in front of the video.

The generated VOB file contains the menu buttons in the stream therefore DVDA must encode the stream itself, doing this outside DVDA will achieve nothing, damn.


As to using a standalone encoder, I think I'd have to spend a LOT of money to get one that lets me manually set the bit rate to different values for different parts of the video, could be wrong here, I've only tried TMPGEnc and the MC one that cames with Vegas.

The good news though is that although I had to drop the bit rate to 3.5 MBits /sec it doesn't look to horrid/ Most of it the only motion occurs in around 30% of the screen as a PIP but the rets is a static still, but in one section the PIP zooms up to full screen, that's the bit I was worried about but it looks OK, should check the bitrate there in the encoded stream, maybe the encoder is smarter than I thought and bumps the bit rate up much higher there.
ScottW wrote on 3/9/2004, 3:27 PM
If all you've done is add text or buttons, I think these are done as a sub picture that will get overlayed on the background video - so DVDA shouldn't have to re-encode. if you've got a motion clip/thumbnail of some sort, then DVDA will have to re-encode.

This is just observation from using DVD Lab. DVD Lab doesn't have an encoder, yet can easily create a motion background with text/buttons. If you want to add a motion clip (thumbnail, whatever) of some sort though, DVD Lab will give you an AVI that you must re-encode for your final menu.

CCE SP will let you adjust specific parts of the encoding (as I recall), it will set you back about $2000.
GaryKleiner wrote on 3/9/2004, 3:34 PM
farrs,

Your understanding is correct.
DVDA will re-encode menu backgrounds, so it's best to bring it in as an AVI. The audio is handled as a separate entity, so AC3 is a good choice.

Gary
mark2929 wrote on 3/10/2004, 12:18 AM
I Was thinking that using a stand a lone, you would get more control. I know professionally encoded CDs ARE sometimes done on a scene by scene basis. But now you have made me realise and I think this is correct. The Vegas DVD Program re encodes any hard work you might do.. So why Bother. IS THIS what you mean. Sorry If I sound like a Dim wit.. But Im learning some good stuff from you "here" Anyway If that is the case and you want to encode at better quality perhaps an outside Firm might be the least expensive route unless its worth the investment in specialist equipment.