Facts about 5.1 Audio Conversions

[tygrus2000]

I see more and more questiosn about 5.1 Dolby Digtial & DTS conversions and I think people should know more about these formats before wasting time on a conversion.

Taking a stereo signal and converting it to AC3 will not give you surround sound. This produces a stereo AC3 file which there is no reason to do unless you want the compression benefits of the format. As far as I know, DTS has no equivalent stereo format.

If you take your stereo file and convert it to R & L mono and then use something like SoftEncode or Surcode to encode 6 seperate mono wave files into a DTS or DD stream, this is not surround sound either. This is 5.1 stereo and the same thing comes out of the RF as does the RS. Note that most recievers can decode stereo files to 5.1 stereo at the flick of a button so converting in the actual file is a waste of time. Also, when you do a conversion like this, keeping the sound in phase is a huge problem and your soundtrack can become unuseable.

The phasing problem can occur if you are surround mixing your own material from scratch as well and is really the realm of sound engineers. I am not saying it cant be done, but you need a good ear and some talents to do this.

Tygrus

[BJ_M]

yes -- exactly what i said also (a number of times)


yes - there is 2/0 DTS , DTS can have 1/0 up to 8 channels (seperate) (and more really)


DTS - as Dolby Digital , uses a different compression process between Film and Home versions

the DTS or Dolby Digtal(ac3) you hear in a theatre is not the same as the one you hear on a DVD

now here is a supprise to you -- the DVD version is ussually better (Dolby).

DTS in a theater uses a higher bandwidth than Dolby Digital (it is played off a CDROM - instead of stored as a picture between sprockets on the film and read with a camera pickup)

[txpharoah]

YES YES YES. Thanks for the post. The recent conversion posts have gotten annoying, especially when you have younger users typing up "nah dude, I can make 5.1, you don't know what youre talking about, converted my mono tape just fine". I figure more work for them, at least it keeps them away from the boards. My receiver emulates 5.1 with a single button on the remote. That's the extent of my "5.1 conversion" work at home.

[FulciLives]

Well ...

The reason I have had some interest in creating a 5.1 AC-3 from a two channel source is this:

BeSweet 2.0 AC-3 files do NOT work on Pioneer players.
However a 5.1 AC-3 file created with BeSweet is NO problem with the Pioneer players.

I know this from doing "frame-rate" conversions in BeSweet where I transcode a PAL AC-3 to a NTSC AC-3

Unfortunately that was when I found out that my Pioneer was fine with a 5.1 AC-3 (when the original was 5.1 AC-3 of course) but not with a 2.0 AC-3 (when the original was 2.0 AC-3 of course).

It is widely reported on the forums that the Pioneer players have this problem ... the inability to properly play back 2.0 AC-3 files made with BeSweet.

However, as you all know, BeSweet is the only FREE program that can do this. All other AC-3 encoders seem to cost an arm and a leg.

SO ... I thought if I could figure out a way to make a 5.1 AC-3 from a 2 channel audio source I could "get around" the BeSweet 2.0 AC-3 problem.

- John "FulciLives" Coleman

[tygrus2000]

I am still not sure I understand your reasons for going to a stereo AC3. Just leave the audio in 2 channel PCM waves files. Every DVD player plays those.

tygrus

[txpharoah]

... the inability to properly play back 2.0 AC-3 files made with BeSweet.

Then don't use BeSweet. DVDit! PE makes 2/0 DOLBY and the program was only $600. The upgrade is less if you have an SE or LE version already (which came with my A03 burner, so I upgraded for much less).

Sonic Foundry SoftEncode is good too, although it is apparently discontinued and was originally $500. However, "used" versions may go for less on eBay and other stores with closeouts on it.

[BJ_M]

you can buy Vegas 4 + DVD Architect for $264 on ebay ..

that will do both mpeg encoding and 5:1 Ac3 encoding (including dolby EX)


you cant beat that deal ..

[feeky1973]

Just leave the audio in 2 channel PCM waves files. Every DVD player plays those.

i have tryed using in this mode but my amp wont then play it in dolby pro logic just stereo. would encoding to 2 channel ac3 give me pro logic sound?

thanks

feeky

[BJ_M]

Just leave the audio in 2 channel PCM waves files. Every DVD player plays those.

i have tryed using in this mode but my amp wont then play it in dolby pro logic just stereo. would encoding to 2 channel ac3 give me pro logic sound?

thanks

feeky

no

[Rickster]

Sonic Foundry SoftEncode is good too, although it is apparently discontinued and was originally $500. However, "used" versions may go for less on eBay and other stores with closeouts on it.

I've been using Sonic Foundry's Acid Pro 3.0 for some time now, and paid the 99 bucks to upgrade to 4.0 that has the 5.1 surround mixing, but no burning capability. I bought the 5.1 plug-in pack last month that includes the Dolby Digital 5.1 encoder to burn the resulting audio files on DVD. You can import your video as an .avi file directly into AcidPro and score your video right in the program. You can assign separate busses for each channel or assign keyframes to animate the moving of sound effects from one channel to the other, in time with your video. You do have to have a 5.1 card installed in your computer and a 5.1 speaker system attached to review your 5.1 projects in real time, but it's well worth the results. I've already done 2 music videos with bands that have paid me to shoot the videos and mix in DD 5.1. I then use TMPEnc to encode the video .avi file to MPEG2 and use the .ac3 file from AcidPro for the audio. I use DVDLab to combined the two and the resulting DVD's look and sound great. My clients couldn't be happier!