DVDA insists on recompressing AC3?

Doug_Marshall wrote on 11/15/2004, 6:45 AM

I've been rendering separate MPEG2 video and AC3 audio from Vegas to avoid the rendering in DVDA. However, DVDA insists on recompressing the audio anyway. Did I miss something? - Doug

Comments

gordie wrote on 11/15/2004, 8:48 PM

what does it want to recompress to? If its AC3, why fight it?
Just give it the wav file and let it happen in the build portion.

cbrillow wrote on 11/16/2004, 6:06 AM

Are you using one of the DVD Architect video stream templates? (PAL or NTSC) If you're using the default mpeg template, or a custom template where "Include Audio" is checked, you're including mpeg audio in the video file, which would require recompressing to ac3.

ScottW wrote on 11/16/2004, 6:43 AM

Is it rendering or recompressing?

If you are actually feeding DVDA an AC3 audio file, then I'm pretty sure it couldn't possibly recompress, because DVDA doesn't have (AFAIK) an AC3 decoder (just like Vegas doesn't include an AC3 decoder) - a decoder would of course be manditory to perform a recompression of AC3.

What you may be seeing is DVDA "render" the audio - DVDA will render audio anyplace that there's video without audio, or in cases where the audio stream is shorter than the video stream.

If you look at the optimize screen during the prepare dialog, you should be able to see what DVDA is actually planning on doing to the file.

--Scott

Doug_Marshall wrote on 11/16/2004, 8:59 PM

Yes, I'm using the DVDA video stream template - no audio. Then a separate AC3 render of the audio.

Doug_Marshall wrote on 11/16/2004, 9:03 PM

I'm pretty confident the audio I'm feeding DVDA is AC3. And the Optimize dialog says the audio will be recompressed. It's hard to imagine that my video and audio renders would come out different lengths from the same project, but maybe they did (or something). Anyway, for the moment, I decided to go with a .wav file and set DVDA for PCM. The file is all music anyway. But I'm still a bit baffled by the info in the optimize dialog... Doug

epirb wrote on 7/25/2005, 2:12 PM

bump Im having the same issue with DVDA 3
and yes the audio is rendered as ac3 in Vegas same as the other chapters but 1 chapter says it must recompress the ac3.

PeterWright wrote on 7/26/2005, 1:35 AM

Don't forget that unless it won't fit on a DVD (? well over 60 mins of video?), you'll get better audio by leaving it as PCM.

ottowr wrote on 7/27/2005, 12:10 AM

I know it's a dumb answer, but have you checked that your project properties specify AC3, and not PCM?

ECB wrote on 7/27/2005, 5:57 AM

I assume the DVDA referred to is DVDA3. First, DVDA3 has a AC-3 decoder. AC-3 audio plays fine on the timeline and if you set the Properties>Audio to PCM DVDA3 will transcode all the AC-3 files you input to PCM.

DVDA3 does not recompress a compliant audio stream. If DVDA3 finds a non compliant audio file DVDA3 will post a message during Prepare that The audio on track ...will be recompressed. On the second step of Prepare click the Optimize button. Click on your movie and then the Audio tab. The properties should show Compliant - Yes Recompress - No. If you want to force a recompress change the Recompress to Yes. Click Okay and see what is listed in the description You will see The audio on track....will be recompressed. Bottom line if DVDA3 does not post the message the audio track...is being recompressed it is not. If you do get the recompression message, and your files fit on the DVD, you have a non-compliant audio file.

Ed B