From Dolby Digital AC3 to Dolby Digital Stereo and back

[moviebuff2]

Hi everyone:

My laserdisc player only has 2 RCA audio outs. Consequently, when I tranfered my laserdiscs onto DVDs with my Philips DVD recorder, the sound was recorded in Dolby Digital Stereo, even though many laserdiscs of mine were manufactured with Dolby Digital AC3 (Surround).

Now, I read that TMPGEnc has its own AC3 Plug-in that can decode and encode sound in AC3 and that can be used with their DVD authoring software.

My question is:

Can this TMPGEnc AC3 Plug-in re-encode the Dolby Digital Stereo sound of some of my DVDs that I recorded from my AC3 laserdiscs? Will the sound be true AC3 or will it be only simulated AC3, like the fake & cheap simulated stereo sound of those CDs re-mastered from 78 rpms and some 33-1/3 and 45 rpms?

Thanks

[guns1inger]

Dolby Digital is AC3. Dolby ProLogic (Stereo) was the analogue process.
Dolby Digital (AC3) can have 1 - 7 channels of audio, giving you 1.0 through to 6.1 audio. If you recorded from the analogue outputs of your laser disc player then you have only recorded the stereo downmix of the original audio. Even if the original was encoded as 5.1 AC3, you have lost all the information required to rebuild the mix.

Tmpgenc's plugin is only capable of encoding to 2.0 AC3, so it won't help you. DAudioK has a 5.1 upmix capability that may give you enough of a simulated mix to make you happy. Worth a look. Soopafresh also has some scripts to do a similar thing. Search the audio forum for them.

[moviebuff2]

If you recorded from the analogue outputs of your laser disc player then you have only recorded the stereo downmix of the original audio. Even if the original was encoded as 5.1 AC3, you have lost all the information required to rebuild the mix.

Thanks, guns1inger. That clarified my confusion. I'm glad I have not bought the plug-in yet.