Dual Channels

[Gaston]

Stereo
Joint stereo
Dual channels

What's the diference?

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If the original sound in DVD is AC3 what I should use (Stereo, Joint stereo, Dual channels)

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Sorry about my english

[DJ Bobo]

Stereo = 2 separate channels
Joint Stereo = 2 channels, but takes advantage of what is common between the channels (example: voice of the singer etc)
Dual Channel = 2x mono-channels; used sometimes to get 2 languages on one stream, one can switch between right and left to get the other language.

There is many types of AC3:
- 5.1: preferably stereo, but you may also use joint stereo with low bitrates. but never use joint stereo for vcd or svcd
- 2.0: stereo, joint stereo for 2.0 stereo or 2.0 surround; mono if the source is mono (many mono streams are encoded as 2.0). here again never use joint stereo for vcd or svcd
- 1.0: always mono. For vcd or svcd you may check the compatibility of your standalone, if it can't play mono streams with vcd or svcd, you may encode your audio as joint stereo.

[Taric25]

So what's the differance between stereo and dual channel if the channels are both seperate?

[DJ Bobo]

well as said, dual channel is used to get 2 languages on one stereo stream, you can switch between right and left to get the other language.
Is usefull to get SVCD with 3 or 4 languages... (standalone must support dual channel mode)

[Shuichiro]

How can I make VCD not SVCD with Dual Channel?

[dani82]

First thing, I use a program called GoldWave for editting sound.

1) encode the video.

2a) extract the ac3 files from the vob file.
2b) convert the ac3 to wav.
2c) load them into Goldwave, and Pan* one the left and the other to the right.
2d) copy one audio, and mix it with the other to have a dual language or multilanguage.
2e) make sure they are insynch with each other and have about 2gb for every 20 mins.
2d) convert the wav into mp2, and multiplex it with the video, and your done.


*Pan - to move the audio to one side or the other (ex. japanese on the left, english on the right)

[Shuichiro]

hey! Thanx. This was simple and helpful. Maybe Is just buy me a DVD Player capable of playing DVD2SVCD reated SVCD with MulitLanguage. Or I just have to buy me a lot bigger HDD and get Goldwave :D

Thank you very much again.

[Taric25]

I still don't understand the differance between Dual Channel and Stereo. What would be the differance between a dual language WAV that I encoded to Stereo MP2 and one encoded to Dual Channel MP2?

Anyway, SVCD supports 2 audio streams and currently 5.0 is possible on SVCD, so it is possible to have 10 languages on a single SVCD. ;)

[dani82]

dual language is two languages, and i think stereo is kind of like if a train goes by, you heard from one ear as it comes by you, both as it passes you, and the other ear as it leaves you; or i may be wrong?

[DJ Bobo]

I'm not sure, but I think if you encode a double-language wav as stereo, you won't be enable to switch between right and left.
But if you encode it to mp2 dual channel, there will be a flag that tells the player that the stream is not stereo, but 2 separated mono-channels, so that the player gives you the choice between right and left...

@ Taric25
I thought SVCD supports up to 2 stereo streams, that means you won't be able to get more than 4 languages.
And I thought SVCD can handle only one Multichannel-MPEG-Stream (so you can't put anything else more), in that case that would be only one language, but may be I'm wrong...

[DarkAvenger]

x: bitrate for channel 1
y: bitrate for channel 2

always: x+y=nominal bitrate

dual channel: x=y=nom.bitr/2
stereo: x<y, if ch2 is more complex for a frame, else x>=y


Anyway, SVCD supports 2 audio streams and currently 5.0 is possible on SVCD, so it is possible to have 10 languages on a single SVCD

A very bad idea....