Dolby Digital 5.1 + DTS recordings...

Feekzoid · Post by **Feekzoid** » 03/01/2003 - 14:18

Lo All, and a happy new year!

A while back we had a discussion about creating dolby-prologic surround audio effects/music, and I showed how to create and implement this.

Well, I've now gone one stage further, by creating a recording of a C64 Sid tune in Dolby Digital EX (6.1 channels!)

Its rather crude, but now I know how to do it the possibilities are splendiferous

The SID tune in question is Galway's Miami Vice title and I have created it thusly:

Channel 1 of Sid > Front Left
Channel 2 of Sid > Front Centre
Channel 3 of Sid > Front Right

I then created a delayed echo+reverb+slow flange recording of the same three channels and mapped these to Rear Left, Rear back/centre, Rear- right.

I dont actually use the .1 LFE channel, but could have

The effect is quite complex but sounds nice, tho you do need to make sure you've got your sound gear levels rigged correctly. In a "real" recording I would not have created such a hard-pan accross the front channels, but I did it this way to make sure that I was getting the discreet channel seperation.

Best of all tho, I can also create DTS-ES recordings also

But these tend to be quite large!

I will upload the .AC3 (Dolby) recording to my webspace later on, but will try to shrink its size somewhat as it is curently 8.11mb due to the 448kbit bitrate. A DTS-ES recording would be at least 768kbps!

For those of you interested in downloading and playing the file you will either need a software AC3 player (powerDVD4 or InterVideo WinDVD4) or a standalone DVDplayer that can play AC3 files through your hifi gear.

Feekzoid · Post by **Feekzoid** » 03/01/2003 - 20:29

Well, couldnt really remaster it to a lower bitrate, sounded wishywashy so

http://www.feekzoid.vispa.com/miami-vice.ac3

DHS · Post by **DHS** » 04/01/2003 - 12:38

This is really interesting. I've been looking around for a way to encode ac3 but found nothing. No plugins (for example, for Cubase SX Surround Mixer), nothing

Anyway, always if can encode in ac3 i cannot play it back. I've no digital exits on my SBLive and the ampli/decoder i use (a Sony STR-DE685) is far from the pc.

I remember you instruction to encode in prologic, but found them a little unpractical. Have been looking for a plugin for this too, and again found nothing.

I think a very interesting topi could be Dolby Prologic II encoding.
With this you can obtain 5.1 discrete channels encoded in a common stereo stream. I believed it to be a stupid solution, with many limitations, just like Prologic, but i had to change my mind. Prologic II rulez!

Any hints on this?

cheers.

Feekzoid · Post by **Feekzoid** » 04/01/2003 - 17:40

Now prologic 2 is something I dont know a lot aboot tho my amp has it. From what I've heard tho its not really discreet (how can it be after all?) as it is still matrix encoded audio within a stereo stream.

As of yet I have not managed to do anytying really with it... but remember DPL2 is not a new encoding process... its a new decoding process which achieves full bandwidth surround material and better centre imaging, as opposed to unique discreet surround (stereo material)

putzi · Post by **putzi** » 05/01/2003 - 1:14

You donÃ‚Â´t need a digital output at your PC to play AC3-files back.
All you need is a program called "HeadAC3he" from http://www.doom9.net.
Use this program to convert the AC3-file to AC3-Wav and burn the WAV-file like any other other audio wave to CDR/CDRW; it works with "Feurio!".
Your DVD-Player or CD-Player needs to have a digital connection to your DD5.1-receiver. Lower the volume before your first try. Not all receivers understand "AC3 via PCM digital audio" and cry out a loud noise.
Another program to make AC3-WAV out of AC3-files is AC3-machine, also from http://www.Doom9.net
I was not able to convert the Miami Vice-ac3-file into AC3-WAV, HeadAC3he says the header is missing and AC3-machine produces an empty file. But it works with proper AC3, I have tested it with Blue Man GroupÃ‚Â´s DVD "Audio" (Last Train to Trancentral

.
If you use HeadAC3he, the AC3-file has to be 44.1 KHz. It did not downsample from 48 to 44.1 in my tests, but AC3-machine did so.

More info here:
http://www.kellyindustries.com/diy_5_1.html

Feekzoid · Post by **Feekzoid** » 05/01/2003 - 10:27

Yeh the 48khz rate was something I had to do to make my DVDplayer play the file (DVD rules state that DVDaudio must be 48khz - and my DVDplayer demands that it sticks to that rule!)

Dont know why the AC3 file is not truly compliant tho, I had to make several tweaks to the file format before it would play correctly on my gear, I might try using AC3fix on the finished output.

I'm going to try an experiment with an Amiga mod next with Dolby Digital.

However, my next big project will be a Sid-remix I'm working on which will be mastered to DTS-ES, and then a DPL Mp3 file.

putzi · Post by **putzi** » 05/01/2003 - 13:38

I am not quite sure if it is really the 44.1 KHz, maybe HeadAC3he does something wrong. The WAV-file has to be 44.1 for sure, because this makes sure that the stream is played back at the right datarate.

Although the output is nothing special today, but having DD5.1 on an audio CD is fascinating!

Is there any chance that you will upload a fixed AC3-file? I really like to hear this Miami-Vice-SID in extreme surround

Sonic Wanderer · Post by **Sonic Wanderer** » 05/01/2003 - 14:59

Does this work on any DVD-player?

putzi · Post by **putzi** » 05/01/2003 - 15:28

You need a CD or DVD-Player with digital output. The device plays a sound similar to a C64 tape, but fully digital. Not every receiver will recognize the DD5.1-signal in it.

Feekzoid · Post by **Feekzoid** » 06/01/2003 - 19:40

Sure. Stay posted for an updated file which I will make fully compliant (or attempt to do so anyway)

I didnt know about ac3-wav playback on CD, just DTS. I will try an experiment with Headac3e just now to give it a go.