"According to the DVD spec, audio must be either PCM (wav file) or Dolby Digital (unsupported by VV) - at least for NTSC systems. The Layer-2 audio is no good if you want to create a DVD image."

As I understand it, PCM and .wav files aren't synonymous. Layer 2 audio is the defacto standard PCM audio format for mpeg-2, hence DVD. That's not to say that the MC codec isn't perhaps putting out a nonstandard layer-2 stream, or at least one that doesn't conform to what your DVD authoring package wants to see. This _could_ be an issue with the authoring package. Have you tried another?

Doug,

Take a look at the following:

"Discs containing 525/60 video (NTSC) must use PCM or Dolby Digital on at least one track. Discs containing 625/50 video (PAL/SECAM) must use PCM or MPEG audio or Dolby Digital on at least one track. Additional tracks may be in any format. A few first-generation players, such as those made by Matsushita, can't output MPEG-2 audio to external decoders.

The original spec required either MPEG audio or PCM on 625/50 discs. There was a brief scuffle led by Philips when early discs came out with only two-channel MPEG and multichannel Dolby Digital, but the DVD Forum clarified in May 1997 that only stereo MPEG audio was mandatory for 625/50 discs. In December 1997 the lack of MPEG-2 encoders (and decoders) was a big enough problem that the spec was revised to allow Dolby Digital audio tracks to be used on 625/50 discs without MPEG audio tracks."

I took this from http://www.dvddemystified.com/dvdfaq.html

So for NTSC disks you must either use PCM or Dolby. Since Dolby requires a heavy license fee, most consumer DVD authoring programs don't support it. Therefore you are stuck with uncompressed PCM audio.

DVD PCM audio, at least my understanding, must be 48K at 16 bits (although higher rates are supported) uncompressed. I thought these files were generally saved as .wav files. I realize, however, that all .wav file don't meet this standard.

The MPEG file generated by the MainConcept plug-in using the DVD NTSC template is DVD-compliant in the sense that it encodes MPEG audio and video data that meets the DVD specs. As you pointed out, MPEG layer 2 audio isn't officially supported by NTSC DVD players (even though some do). However, a way to store PCM or Dolby AC3 audio in an MPEG file isn't defined by the MPEG spec.

A DVD authoring system doesn't simply burn an MPEG onto a DVD. It creates a VOB which contains additional information about chapters and menus. A VOB also defines a way to store PCM and Dolby AC3 audio. Some DVD authoring software has the ability to convert the MPEG layer 2 audio to PCM or Dolby AC3 when generating the VOB. While other authoring software will accept a WAV file as audio input (which you can render from Vegas).

Don,

In Sonics DVDit, when DVDit demuxes the file it then transcodes the layer2 to PCM for me. I would be surprized if Reel DVD did not do the same for you. I know that Reel DVD was not originally a Sonic product so maybe it won't.

Just a thought. Besides, I would do your MPEG 2 encoding including audio in another aplication. VV is a good editing tool but is not meant for high quality DVD/mpeg encoding. Render the project to DV or umcompressed and then enocode it with hardware(prefered but expensive) or drop to a specialized program like TMPGenc.

I am aware of all of this. I use MyDVD to create the DVDs that I want. Authoring programs generally don't do a very good job of encoding/transcoding. I usually take a project and render it twice. Once for the MPEG Video Stream, and once for a PCM Audio Stream. I then drop these two files in the MyDVD and all works well. If you take a MPEG Audio/Video Stream and drop in into MyDVD, MyDVD extracts the audio out and automatically converts it to PCM. This is a SSLLOOWW process and you don't really know what your final DVD Image size will be until after the process is done. In some cases it is too big for a DVD disk!

Therefore, in general I believe that it is better to give the authoring program seperate audio and video files and let it simply build the VOB files. Because of this it would be nice if there was a VV template that would do the rendering of the two files at once. Maybe have a check box on the audio tab of the template to allow for MPEG Layer 1, or MPEG Layer 2 embedded streams, or PCM, Dolby Digital Stereo, or AC3 seperate files. I realize that there is a steep license fee for the Dolby stuff, but that could be included as a seperate add-on (just like the MPEG encoder).

Finally, MPEG audio is not a compliant audio format in NTSC compliant DVDs!!! It's ok for PAL, but not NTSC. If I look at the comments in the NTSC DVD template, it states that it generates a DVD compliant file. I think this could be misleading to a lot of people since further processing (rendering/transcoding) needs to take place on this file before it can be used.

Hi from MainConcept,

This issue will be addressed shortly. As discussed here and in another thread, the short-term workaround would be to generate the files separately if you have to have separate assets.

NOTE: Though the NTSC DVD spec does call for PCM or Dolby audio, MPEG-2 audio works in most cases. So if you are making a DVD for personal use, you might get fine results without having to encode the video and audio separately. If you're not sure, I would suggest the workaround until a tweak is released.

Best Regards,
MainConcept Tech Support

Good reading! I stand corrected.

Thanks for the info. Do you know of any "consumer" priced DVD authoring systems? I use MyDVD and its pretty crappy, but it's only $99. (When compared to $150 for VV it's not a very good bargin!) MyDVD will accept the VV mpeg file, but needs to demux it and transcode the audio to PCM. This is a very slow process. Using two files is much easier and quicker!

It's a simple process in VV to render twice. The audio render is very quick (compared to the video render).

Now what I really want is to be able to author the DVD from within VV and burn it directly to disk!!!!! Ok, I'm dreaming.

DVDit ($300) or the new program from MAC are about it for the low priced DVD authoring. The MAC program is the old Spruce software and is the best in most any price range in my book.

Real DVD authoring doesn't start until about $1200 which would be something like ReelDVD from Sonic Solutions. Even that lacks a lot of ability. DVD authoring software is stll a lot of blackbox and magic. As consumer level writers gain popularity I am sure that DVD authoring capabilities will also trickle down to the consumer price range.

k