Hi Musicvid, thanks for responding. I found a thread where the following settings were suggested:

Dialog normalization -30 dB, Line mode profile = None, RF mode profile = None

I tried this and -although the overall volume is higher- the audio sounds muffled. I think I'll switch to uncompressed LPCM, on BD I have ample bandwidth for that. However, I was asked for a number of copies on DVD and there I would prefer AC-3 because of the limited DVD bitrate of 9800.

AC-3 from the Studio Stereo DVD template sounds good but as soon as I get it into DVDA, it is recompressed and spoiled.

Lou

Lou

Without getting into the settings in the AC-3 Pro encoder this sounds more like a Project options set up problem in DVDA.

My first approach is, "if it ain't broken don't fix it" so if the AC-3 Studio stereo template is working for you I wouldn't change from it.

One question is what software are you using to check it before burning onto a DVD so you know it is OK?

As to your AC-3 stream being recompressed the question is why DVDA is choosing to recompress it, something that should never happen to any AC-3 signal as it will destroy the quality of the end product.

Can you look at the project settings for DVDA and post them on this thread?
During the build/burn process in DVDA what dialogue boxes are presented?

You have the option to change the video and audio compression settings at that point if you get a message that either is going to be recompressed and you know it is already in a correct format.

Sorry I can't give more info at present but I'm currently booted into the Mac side of the world and can't load either program at present.

New Hope Media

Newhope,
When you find time, could you please look at my latest post in the Audio forum and see if you can duplicate the downmix bug I'm experiencing and post your impressions there? Many thanks!
http://www.sonycreativesoftware.com/forums/ShowMessage.asp?MessageID=612060&Replies=0

Looked at it already.
I'll give it a try when I get a moment but i'm editing in FCP at the moment so need to get that done before I can reboot in XP and run Vegas/DVDA.

I'll post as soon as I do.

Regards

Steve
New Hope Media

Hi Newhope, thanks for looking into this.

However, in the meantime I have come to the conclusion that this not recognising a compliant AC3-file produced with the Studio Stereo DVD template is nothing more than a bug in DVDA, because when I use the Pro template, DVDA accepts it. And if DVDA concludes that recompression is required, you cannot change the compression setting at all, it is greyed out.

I'll send Sony a note about this and report back here.

Lou

Lou et al,
I've run some exhaustive tests with calibration test tones and done extensive reading of the Dolby metadata specs, and in reference to your question about the most accurate reproduction with the AC-3 Pro Encoder, I am prepared to make the following recommendations with notes:

If you're doing AC-3 Stereo, you can ignore everything I say about the Phase Shift option, it's greyed out of course.

Dialog Norm at -31 (this sets it at unity gain)
RF and Line Mode DRC Off (WYHIWYG)
DC High Pass Filter On (this operates at <=3Hz and takes DC bias out of the mix)
Bandwidth Low Pass Filter On (this takes aliasing noise at >20kHz out of the encode, but it also lowered the rendered volume by -0.1dB in my tests)
90 Deg Phase Shift On (makes it easier for Pro Logic decoding on older equipment, Dolby says it is inaudible in 5.1 except in "very rare" cases)

Everything else can be left just as it is in the 5.1 DVD template; the only difference I can determine compared to the Studio encoder is the 90 Deg Phase Shift, but turning it off replicates the downmix pan bug I reported in the Audio forum. Interesting, huh?

I'm going to try to replicate the AC-3 Studio Stereo recompress issue in DVDA you reported sometime this week, since I have a little spare time on my hands.

Musicvid,

I did a trial run with your recommended settings and now the original and the AC3 version sound very similar, although when I use LPCM the audio seems to have a bit more clarity, but this may be my imaginative 78 years old ears.

Thanks for your tips!

Lou

Oops! I'm (luckily) only 68 years old. But when you get older, the number of typos also rises...

**...although when I use LPCM the audio seems to have a bit more clarity**

You are probably correct about that. It has been a criticism of AC-3 since its early days. The positive tradeoff is the compression (8:1 for stereo) and file sizes compared to LPCM.

**However, the Studio AC3 encoder produces AC3 streams that are recompressed in DVDA5,**

Lou, I was unable to duplicate your problem. In fact, my test project in DVDA5 prepared in 12 seconds flat, no rendering or recompression of any kind. The details of my test:

-- Vegas Pro 8.0b, rendered in AC-3 Studio Stereo template, AGC off.
-- DVDA5 Audio Project settings: AC-3 Stereo, 192Kbps
-- Put the audio on the timeline with no video, prepared the project, no messages or recompression. It did "render" the blank video to black frames as would be expected. This took less than a minute.
-- Put some mpeg-2 video on the timeline with the audio, prepared in 12 seconds, again no messages, no recompression of any kind.

If you are preparing audio only, it may be the blank video "rendering" that has caught your attention. Otherwise, your audio project settings in DVDA may not be exactly as your audio, or you may be exceeding disc capacity (unlikely). In any event, it is not something I can replicate on my setup.

EDIT: Lou, when you "Prepare" or "Burn" and get to the "Review Message List" window, click "Optimize" then the "Audio" tab, and set "Recompress" to "No." I bet this will do it. HTH

**Lou, when you "Prepare" or "Burn" and get to the "Review Message List" window, click "Optimize" then the "Audio" tab, and set "Recompress" to "No." I bet this will do it. HTH**

Musicvid,

When DVDA concludes that recompression is required, the Yes/No Recompress option is greyed out.

I'll check once more, but I think my project settings match those of both AC3-files, once prepared with the Studio template and once with the Pro one. DVDA recompresses the Studio one but not the Pro one.

I'll report back when I find what's happening. Sony's response apparently was from a catalogue of standard answers and hadn't much bearing on my query.

Lou