Newbie re-render question

cbrillow wrote on 6/1/2004, 5:41 AM
I'm feeling my way through DVDA2 with the manual and the excellent NAB video tutorial, learning a thing or two every time I use it.

Yesterday, I created a simple project with a 1/2 hour program and used the built-in automatic scene selection menu facility to create the "Play all/Select scene" scenario. Was a little disappointed that this doesn't provide the option to return to the menu after each chapter -- I thought that could be handled by end actions. At any rate, I'm aware from reading other posts here that this is accomplished by adding multiple instances of the source video to the project and adjusting in/out points. So this isn't the issue -- I'm merely describing the project as setup for the actual question.

I like to start "simple", so the initial version used menu buttons with default, static thumbnails. Subsequent versions used motion thumbnails and I eventually burned a couple of full-length tests on DVD+RW. One of my modifications was very simple: On the main menu, which contains only "Play Feature" and "Scene Selection" buttons, (both initiatlly were set to the same first frame of the source video) I changed them so that the thumbnailsl would show different stills from the video.

Then I went to create/burn a DVD, and DVDA2 insisted on re-rendering the entire project. Is this correct? Shouldn't there be temporary files leftover from the previous version that could be used? It seemed like a small change to a title/menu page wouldn't result in a complete re-do. Did I do something wrong?

Thanks in advance for any comments.

Comments

bStro wrote on 6/1/2004, 7:37 AM
Your video should be a DVD compatible MPEG2 file before you bring it into DVDA. If you created / edited your video in Vegas, use the NTSC DVD or DVD Architect Video Stream template for the video and the AC3 template for the audio. If your video is already in the proper format before you bring it into DVDA, DVDA will not re-render it -- only prepare it, which takes little time at all.

If your video is not rendered properly, DVDA will always try to render it before preparing and burning it.

Rob
cbrillow wrote on 6/1/2004, 9:38 AM
Aha -- makes sense. Thanks for the prompt reply.
johnmeyer wrote on 6/1/2004, 11:06 PM
The workflow that Sony recommended in these forums over a year ago is to render in Vegas. That way, as you have found, if you make changes in DVDA, all that must be done is the "prepare" part of the operation which is a simple multiplex and file copy operation. If you prepare to a different disk than where your source files are located, and if the files have already been rendered in Vegas, the prepare operation can happen in just a few minutes.
cbrillow wrote on 6/2/2004, 7:50 AM
Thanks, johnmeyer. Good information, but it raises a couple of questions:

1) Why prepare to a disk that's different from the one where the source files reside? Is this a speed advantage realized by doing reads & writes to different physical disks?

2) If I render to MPEG in Vegas using the NTSC DVD template, and I have, say, 2 hours of source material, DVDA will have to recompress to fit to DVD, won't it? In this case, it would appear that the perceived advantage of rendering in Vegas would be negated. Also, wouldn't this recompression result in an inferior result to supplying the source to DVDA in DV AVI form, where it would only have to go through one compression to the appropriate bitrate to fit on a disk?
johnmeyer wrote on 6/2/2004, 9:38 AM
Why prepare to a disk that's different from the one where the source files reside? Is this a speed advantage realized by doing reads & writes to different physical disks?

Yes, you are exactly correct. The difference is not subtle. Test it yourself by taking a large file (say, 300 Mbytes) and copying it to another folder on your disk (you have to press the Ctrl key if you use Explorer to drag it to its new location; otherwise it will move, which happens instantaneously). Then, copy it to another physical disk (it must be a different physical disk, not simply a different drive letter partition on the same physical disk). You should see something like a 1.8:1 difference. Not quite 2:1, but close.

If I render to MPEG in Vegas using the NTSC DVD template, and I have, say, 2 hours of source material, DVDA will have to recompress to fit to DVD, won't it?

No this is not correct. The key to whole thing is setting the MPEG-2 bitrate in Vegas so that the movie just fits. Use the bitrate calculator found here:

Bitrate Calculator

to find the bitrate to use. Then, use the Custom button when encoding the MPEG-2 file in Vegas and change the Average bitrate (for the DVD Architect template) to the figure given by the calculator. The project will then be encoded at a size that will just fit, without DVDA having to do any recompression. Also, compress your audio using the AC-3 stereo template. This must be done using a separate render (i.e., you do one render for the video, and then a separate render for audio).
cbrillow wrote on 6/3/2004, 6:52 AM
Thanks for your time in replying to this.