Answer to why DVDA will "recompress" AC3

cheroxy wrote on 5/2/2005, 9:06 AM

I searched a few years worth of this question in the different forums and only found questions with no answers. I posted the question a few days ago and also didn't get an answer. Over the weekend I was rendering cartoon files I recorded off tv for my kid to watch on our trip. Poof, the light turned on and I figured out why sometimes I (and probably the others that posted the question) get a rerender of our AC3 files. As you might assume the problem is with the user not the program.

What I have been doing is rendering the video as a slightly compressed mpeg2 file and then rendering the audio as ac3. The problem comes because I left the render audio box checked without knowing. So when I drop the video into DVDA and assume it will attach the ac3 file, it doesn't because it already has the audio included. I have to go back and replace the audio on the DVDA timeline with the ac3 version. Just a slight overlook can cause a lot of frustration. I hope this helps if anybody has the same problem. It is really frustrating to spend a couple hours rendering out all that audio just to have DVDA do it again redundantly. Now I just have to say sorry to the program because the fault was mine :(

Comments

Spot|DSE wrote on 5/2/2005, 9:09 AM

Cheroxy, glad you found it. A guy on the DMN was asking the same question, and it took us a while to realize he wasn't dragging the AC3 file up. Now,...if you store the AC3 with the SAME filename as the MPEG in the same folder, DVDA 1, 2, and 3 will all recognize it and import it for you.

cbrillow wrote on 5/2/2005, 9:48 AM

Given that Cheroxy was using a template that already includes audio within his MPEG file, what would be the consequence of trying that, Spot?

Would DVDA still trying to import the like-named AC-3 file? Might have to try this just to see what happens...

cheroxy wrote on 5/2/2005, 10:21 AM

It doesn't automatically do it even if they are in the same folder and have the same name. That is why I couldn't figure it out. It must default to the included audio in the mpeg2 rather than the ac3 in the same folder.

cbrillow wrote on 5/2/2005, 11:01 AM

Yup, I believe the default template includes audio in the MPEG, which is one reason I virtually never use it.

You've posted some good info, though. Think there was a time early on in my experiments with DVDA-2 that it failed to find the AC-3 file I'd rendered, despite it's having the same name as the MPEG. I didn't take time to try to figure out why, and it never happened again. But this sounds like the probable reason. Good thing to file away in memory. (too bad it's "write only" these days...)

Spot|DSE wrote on 5/2/2005, 11:13 AM

The DVD Architect NTSC Video Stream template doesn't include audio. Are you using some other template?

Chris H wrote on 5/2/2005, 12:05 PM

I have a related question. I use the "DVD NTSC" template when rendering projects in Vegas. When I bring them into DVD Architect I let DVDA render the audio to the AC3 format. Will I get different results by rendering the video stream and the audio stream separately in Vegas? If so, how do I bring those two separate streams into DVDA?

Chris

B.Verlik wrote on 5/2/2005, 1:28 PM

I'll describe this as quickly as possible. 1st, when it's time to render, do the audio first. Render it in AC3, ( go to the AC3 section and find out the ideal way to set up your AC3 rendering. You might as well research this, or you won't understand if I just tell you a shortcut.) You'll get a much better, louder sound file this way. Once you render the AC3, you can open up DVDA and make sure it works. (If any portion of your audio track is a "C" hair too loud, it wont render right.) You can play it by itself in DVDA. (so far, in my experience, if it even starts to play good, then it's okay.) Once you know it works, dont bother saving the DVDA file. Just close it.
Now render you Mpg2. You need to get into the settings and shut off the 'record audio' too section (go into "custom" button, then audio tab, and uncheck "include audio stream". Now render your mpg2.
Just be sure both your new AC3 and mpg2 files are in the same folder when your done and DVDA will put them together. You'll be surprised at the volume difference once you've figured it out.
Now when you create these new render options, don't forget to give them a "name" and save them as a setting (the Icon just to the right of the setting title)to be used later without having to reset them up again.
PS: You can do a search either here or in the AC3 section and find your answers about the ideal settings for AC3 files, but the most detailed answers will be from Dolby labs themselves. (links are included in some of the files here, when you search for them.)

cheroxy wrote on 5/2/2005, 1:52 PM

spot, I was not using the DVDA NTSC stream. I almost always use that, but I did this as a preset that I have from a long time ago for rendering a recorded cartoon. That is why I missed the audio inclusion.
Thanks