3 tracks from stereo

[scypior]

Hi!

This is my first post, and i'd like to ask you about something i've read on another forum:
http://www.recordingproject.com/bbs/viewtopic.php?t=7980

Is that possible? I've tried to do this, but i've got lost somewhere and didn't accomplish it And there is no simple conclusion in that thread

Ps. Sorry if my english is bad, im from Poland

 

[dgatwood]

Their math is wrong. Either a + b=G + 2V + b or a=G+.5V and b=B+.5V.

No, this cannot be done this way. Any addition or subtraction will, at best, result in either one of the original terms or one of the summed/sutracted terms (possibly times a constant).

Read about how Dolby encodes/decodes stuff here.

a = G + .5v
b = B + .5v

a-b = G - B
b-a = B - G

a+b = G + B + V
a+b + a-b = 2G + V = 2 * (G + .5V) <-- original term * 2
a + a-b = 2g - b + .5v

[ a + (a-b) ] - [ (a+b) + (a-b) ] = G+.5B + G - B - [ G + B + V + G - B ]
[ a + (a-b) ] - [ (a+b) + (a-b) ] = -.5V - B <-- inverse of b.

We could go on for any arbitrary number of operations and the results will always be the same. The original three values cannot be recovered in this manner.

 

[scypior]

Thanks!

I've read this pdf, but don't quite catch how decoding works. In Fig2 they're extracting the Surround channel. Ok. But what with the L and R?

--

Found this: http://www.headwize.com/tech/dolby1_tech.htm

So, the S channel is still in L out and R out. And that's all i wanted to know. Thanks!