Quantcast How does the Surround Sound Work? - digitalFAQ.com Forums [Archives]
  #1  
07-25-2003, 05:31 AM
audioslave audioslave is offline
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I've always encoded my KVCD's audio with dual channel in HeadAC3e. Do I need to set up my DVD in a special way to get the surround sound? Or do I have to have a special function on my surround amplifier? Is the KVCD surround a simulated surround or should I have sound in all speakers? Don't get me wrong, I get sound, but I would really like to get surround sound.
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  #2  
07-25-2003, 05:39 AM
new_bee new_bee is offline
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Since VCDs only support stereo-sound, your .mp2 file features, as you said, stimulated surround. If you want the sound on all speakers you have to do this on your surround amplifier. Look it up in the manual, most amplifiers can set all stereo sources to surround (I like listening to Metallica's S&M CD that way )..
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07-25-2003, 05:51 AM
jorel jorel is offline
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turning it worse:


dvd2avi loose the dolby prologic information of audio tracks,
is extract as a normal ac3 2 channels and
the receiver don't "feel" as dolby prologic.

extract the audio with your ripper....try smartripper.
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07-25-2003, 06:02 AM
new_bee new_bee is offline
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Didn't know that!
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07-25-2003, 06:29 AM
Dialhot Dialhot is offline
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Quote:
Originally Posted by new_bee
Since VCDs only support stereo-sound, your .mp2 file features, as you said, stimulated surround.
Not at all !

You can have true surround in stereo-sound. That is the purpose of Dolby Surround encoding (and Dolby Prologic decoding) : to matrix surround channel C+R (center and rear) into the two stereo chanel L+R.

Simulated surround is when you do not have C+R matrixed in the stereo chanel and you "create" a sort of surrounding echo that opens the sound field and tries to give the illusion of a rear channel that does not exist.
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07-25-2003, 06:34 AM
audioslave audioslave is offline
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So how do I rip and encode the audio to get "real" surround?
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07-25-2003, 06:41 AM
Dialhot Dialhot is offline
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Quote:
Originally Posted by audioslave
So how do I rip and encode the audio to get "real" surround?
You ask to DVD2SVI to extract the AC3 without doing anything on it. And you transform the AC3 track into "dolby surround encoded into stereo" track with headache (see option, you can choose "stereo", "surround", or even "surround2" for better work with a DPL II compatible receiver)

But as told by Jorel, do not do the convert AC3->Stereo directly from DVD2AVI.
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07-25-2003, 07:46 AM
Jellygoose Jellygoose is offline
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So are you saying the AC3 files that are output by DVD2AVi are not 5.1 but only stereo??
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07-25-2003, 08:21 AM
Dialhot Dialhot is offline
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If you are talking to mee Jellygoose, no I didn't said that. Jorel did but I think he is wrong.

What I said is that the downmixing from AC3 to dolby surround must'nt be done with DVD2AVI as it does it very badly.
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07-25-2003, 09:32 AM
Jellygoose Jellygoose is offline
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Quote:
Originally Posted by Dialhot
If you are talking to mee Jellygoose, no I didn't said that. Jorel did but I think he is wrong.

What I said is that the downmixing from AC3 to dolby surround must'nt be done with DVD2AVI as it does it very badly.
Well I don't think so either. I do the downmixing with Headache, and it seems to work pretty good. however my receiver gives me jerky sound with the rear speakers when I use Dual Channel as Compression mode...
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07-25-2003, 10:48 AM
jorel jorel is offline
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Quote:
Originally Posted by Jellygoose
Quote:
Originally Posted by Dialhot
If you are talking to mee Jellygoose, no I didn't said that. Jorel did but I think he is wrong.

What I said is that the downmixing from AC3 to dolby surround must'nt be done with DVD2AVI as it does it very badly.
Well I don't think so either. I do the downmixing with Headache, and it seems to work pretty good. however my receiver gives me jerky sound with the rear speakers when I use Dual Channel as Compression mode...
i confirm...you loose "details"
dvd2avi extract as a normal ac3 2 channels and
the receiver don't "feel" as dolby prologic.
you have to choose "force to dpl" (manual) in the receiver.

try extract the audio using smartripper!
will be different.

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07-25-2003, 01:53 PM
audioslave audioslave is offline
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@jorel
How do I rip the audio with SmartRipper?

EDIT: Do I go to the "Stream Processing" tab, choose "Enable Stream Processing" and the right audio track, choose "Demux to extra file" and then press "Start"?
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07-25-2003, 02:14 PM
audioslave audioslave is offline
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Do I have to do something to the audio to get it in sync with the video? I mean, the movie on the DVD is NTSC 29,97 fps but 99% FILM so I process the movie with ForceFilm in DVD2AVI. If so, what software do I need?
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07-25-2003, 02:26 PM
jorel jorel is offline
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audioslave my friend,
you wrote:
"Do I go to the "Stream Processing" tab, choose "Enable...
....to extra file" and then press "Start"?"
yes,and you can uncheck the stream that you don't want!


"....audio to get it in sync with the video..."
see the "audio delay"(ms) in the log of the ripper.
something like this:
0x80 - AC3 - 6ch / 48kHz / DRC / Delay: -67ms
than set the delay in your audio encoding program to -67ms!


"...DVD is NTSC 29,97 fps but 99% FILM so I process the movie with ForceFilm in DVD2AVI."

this i don't know,maybe will need to change the frame rate of the audio!

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07-25-2003, 02:30 PM
audioslave audioslave is offline
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Thank you very much, jorel! Just wanted to be sure. So if I rip the audio this way and then encode it with HeadAC3e I should get true surround sound, right?
Well, does anyone else know what to do with the audio? Do I need to change the audio frame rate to get it in sync?
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07-25-2003, 02:41 PM
jorel jorel is offline
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audioslave,
please read my last post again,i edit and put some more details!

you can use HeadAC3he(very,very cool) and adjust this values:
destination format= mp2(of course)
resample= your choice....if your player suport,
use 48k... is better and size change just a little.
downmix type= surround2
bitrate=more bitrate,better quality but more size..your choice!
channel mode=dual channel

will be great!

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07-25-2003, 02:44 PM
audioslave audioslave is offline
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Thanks again friend! What does the "Booster" function do?
And I still need to find out if I need to change the audio framerate...
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07-25-2003, 02:52 PM
jorel jorel is offline
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let booster as default=1

my little big hint:
i choose normalize to 98% cos with 100% sometimes got clicks like
little explodes....and i'm really bored with sound.
when the sound is normalized,the low volume encrease and
the high volume decrease,trying to make a "media" of the audio.
in one movie,we have more "low volumes" than "high volumes",
than normalizing the sound to 100%,can turn it "unreal" and too loud.
i think that the proud volume is the amplifier that give to you,
not the source at 100%...
100% is the last pass to got saturation and distorcions.

i wait that my horrible english don't turn it all more confuse!

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07-26-2003, 03:10 AM
new_bee new_bee is offline
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"Not at all !

You can have true surround in stereo-sound. That is the purpose of Dolby Surround encoding (and Dolby Prologic decoding) : to matrix surround channel C+R (center and rear) into the two stereo chanel L+R."

Well, that's a matter of definition. The 2 Dolby-Modes Headac3he has built in are "psycho models". If you mix l+r+center+rear into stereo you can't separate them afterwards, but you can give the impression by altering c+r's sound. It may be that Dolby ProLogic amplifiers manage to seperate them, but I wouldn't call that real surround..
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07-26-2003, 06:44 AM
jorel jorel is offline
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Quote:
Originally Posted by new_bee
"Not at all !

You can have true surround in stereo-sound. That is the purpose of Dolby Surround encoding (and Dolby Prologic decoding) : to matrix surround channel C+R (center and rear) into the two stereo chanel L+R."

Well, that's a matter of definition. The 2 Dolby-Modes Headac3he has built in are "psycho models". If you mix l+r+center+rear into stereo you can't separate them afterwards, but you can give the impression by altering c+r's sound. It may be that Dolby ProLogic amplifiers manage to seperate them, but I wouldn't call that real surround..
ok new_bee my friend

i'm with you in this explanations:
"but I wouldn't call that real surround"

little hint:
using dual channel,give the same size as stereo but
dual channel use real 2 individual channels,one for right,another for left.
then,what is in one channel don't "interchange" with other channel.
means...you don't have "leftovers" from other channel,
they are really individual,and one channel don't "corrupt"
(mix in background) with the other channel.
the result is clean.
you can feel it easy encoding mp3 with musics that have
real separations between channels....use the "balance" and
you feel that one channel is really separate from other with dual channels!

hey,this link show big details and tests about quality:
http://rarewares.hydrogenaudio.org/t...sentation.html
seems of topic but is cool,help a lot!


ps:
i love music, listen everyday...every time.....all the time.
for me all little detail is important...!

ahh,...sorry my bored poor english!
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