Over the years here a few people have noticed that 5.1 DVD-A's made from dts sources sound much better than those made from Dolby Digital (ac3) sources. I think I've figured out why and at least one method to address it.

The reason: many DD streams have almost no LFE (low frequency effects) channel content. Most decoders translate the LFE channel to the SW channel for 5.1 audio. The result is a DVD-A made straight from this kind of source does not use the full range of the audio system since the sub is left out.

The solution: I check the LFE channel level using Adobe Audition. If there is little to no content there, I use Audition to combine all six channels into a new single track, run a Fast Fourier Transform (Only the Subwoofer preset) on the new track, and substitute it in for the original LFE track. If the level is still too low I amplify the new SW track by 3dB. Then I use the Audition Surround Sound Processor to write a new 5.1 .wav with my new SW track, and burn it to DVD-A using Cirlinca DVD-A Solo (nice program for $35).

A similar method could be used with just about any multitrack sound editor, and I'll bet Adobeman will come up with a free script to do this too if we give him enough time.

Mike

 

So now folks are betting on me... What are my odds looking like in Vegas these days ?

I've always thought that DTS sounds better than DD5.1 for movie sound tracks but there are a lot of variable as to why. DTS is a different compression algorithm than DD. It is typically used at a higher bit rate (448K vs 384K). To me DTS and DD are near equivalent for the big "boom thump" stuff in sound tracks but when the musical parts of the score come forward DTS always seems better. Then there is the whole dynamic range difference. DD has information that allows modification of dynamic range at playback and DTS, I believe, does not. So when comparing DTS to DD there can be large differences in dynamic range and that will color opinions.

Add to all of that what you observe in Audition and no wonder there is an audible difference.

Now, back to the odds.

Audition is a really, really capable product but I don't think I'll do any scripting for it since it is pretty rare to have for most people. But, what I will suggest is that you look into BeSweet. Yup, I'm sweet on BeSweet alright. It will allow you to do all kinds of remixing on DD streams. I haven't played around too much with it since I tend to like to preserve original content but I think it will have enough to get you where you want. It won't let you visualize wave forms like Audition but since you can tell BeSweet to make individual wav files for each channel you can always compare them in a wav editor later.

In particular look at the -azid() section options for BeSweet.
Ref: http://dhost.info/kpex/guides/bs_clref_html.html for a BeSweet reference. I think most of it's switches tend to mix LFE into other channels rather than other channels into LFE.

I say the odds are against a script. The DVDA GUI project took a lot of time and my family is still yelling at me to spend less time at the 'puter.

 

BeSweet is what I use to get the AC3 out to separate .WAVs. And you are right, it will mix LFE into other channels but it won't create an LFE that I could find.

I was thinking you would know of some free little utilities that take the .WAVs and do what I'm doing in Audition but without needing it. As I learn Audition I'll probably just write the scripts for it myself.

Mike

 

Ya better believe DST is the best! Well I haven't heard DD-HD yet. But in the world of DVD-A DTS is KING!! Here is a link that will give some more info. http://en.wikipedia.org/wiki/Dolby_vs_DTSThe link can be followed, and followed, there lot's and lot's of info on the net about this. Just do a search....