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Dolby Surround games; primitive surround sound on SNES 
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Joined: Sun 17 Apr 2011, 18:59:21

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Location: Oita, Japan
Post Dolby Surround games; primitive surround sound on SNES
There are a few games, like Jurrasic Park, that sport Dolby Surround logos and have a "Surround" audio mode. This isn't Dolby Digital, but an analog precursor of sorts. Supposedly the implementation was once widespread, but who knows now because it's antiquated. Is there implementation in higan / is any necessary since the audio codex would have been in the game cartridge / what was the relationship like for games with Dolby Digital and the SPU?

I have a Dolby Digital amplifier on fiber optic spdif; if there were a way to implement Dolby Surround -> Dolby Digital (AC3) it may be possible to get much better sound for these games. There is however, debate regarding just how "surround" the Dolby Surround implementation was. As it is now, it comes over spdif auto-detected as plain Stereo by an amp which should be able to detect "5ch Stereo"; DTS; Dolby Digital (Prologic II (Cinema; Music)) (no documentation to see if my amp supports Dolby Surround natively)...

::EDIT::
come to think of it, i could swap around some wires and/or pci cards to try out analog surround; but that's a lot of work for what i expect to be an equally great disappointment.

Wed 09 Apr 2014, 17:28:25
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Post Re: Dolby Surround games; primitive surround sound on SNES
viewtopic.php?f=3&t=1241

I imagine there are some answers for you in that thread. I'm not really familiar with any of this. There is no special hardware in the SNES or the cartridge to handle Dolby, though.

Wed 09 Apr 2014, 17:42:01

Joined: Thu 02 Jun 2011, 01:36:41

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Post Re: Dolby Surround games; primitive surround sound on SNES
The SNES games, and later N64 and Gamecube games that support surround are just stereo signals designed to be processed by Dolby ProLogic surround. Just set your receiver to that and you're good to go.

Wed 09 Apr 2014, 23:26:38
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Post Re: Dolby Surround games; primitive surround sound on SNES
SNES games usually triggered this by using phase inversion, by setting one of the stereo volume registers to a negative number. Seiken Densetsu 3 was capable of setting the entire damn global volume to phase inverted, which the popular SPC set uses. Star Ocean could selectively phase invert individual channels.

This level of ProLogic could presumably only be interpreted as limited surround information, delegating perfectly phase inverted waveforms to a rear center speaker, or both rear speakers in a quad or 5.1 system.

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Thu 10 Apr 2014, 01:35:11

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Post Re: Dolby Surround games; primitive surround sound on SNES
Minor correction: Dolby Surround is actually the predecessor of ProLogic, not a level of support.
And yeah, it was three channel. Left, right, rear.

It also, to my understanding, had steering issues due to it's extremely simplified decoder, and sounds that panned across the front generated a lot of rear crosstalk(likely not an issue for SNES implementations, though).



Pro-Logic and ProLogic II and so on improved things greatly by increasing the number of channels and including logic to help separation.
And interestingly, the benefits of ProLogic fell backwards onto existing Dolby Surround video releases, since they were using the theatrical Dolby Stereo soundtrack, which DID have a center channel embedded and WAS designed for this extra logic.
In fact, the Dolby Surround decoders initially came into existence because the sound tracks were already out there in homes(since they functioned as stereo mixes without a decoder, studios saw no reason to remix the soundtrack for a home release or TV broadcast), so there was a large pre-installed media base.

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Thu 10 Apr 2014, 04:13:47

Joined: Wed 09 Nov 2011, 20:30:49

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Post Re: Dolby Surround games; primitive surround sound on SNES
Yeah it won't work as Dolby Digital but most receivers can manually be set to Dolby Pro-Logic I believe. It will definitely work. I tried it out years ago with Zsnes and was surprised to discover it worked quite well for a LOT of Snes games in fact there were very few where you didn't get some sort of positive effect. Despite very few games officially being endorsed by Dolby there is some fairly convincing surround sound in others.

Fri 11 Apr 2014, 18:33:07

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Post Re: Dolby Surround games; primitive surround sound on SNES
jebbyderinger wrote:
Yeah it won't work as Dolby Digital but most receivers can manually be set to Dolby Pro-Logic I believe.

I think it's a mandatory part of DD licensing, is also supporting DPL something-or-other.

Quote:
I tried it out years ago with Zsnes and was surprised to discover it worked quite well for a LOT of Snes games in fact there were very few where you didn't get some sort of positive effect. Despite very few games officially being endorsed by Dolby there is some fairly convincing surround sound in others.

You mean the ZSNES surround toggle?

We're talking about games that ACTUALLY have surround sound in them, not ZSNES hacking the audio to make sound come out the back.

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Sat 12 Apr 2014, 04:00:24
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Post Re: Dolby Surround games; primitive surround sound on SNES
Actually, ZSNES' thing was something I came up with while trying to imitate SRS 3D. It's basically just something that increases the stereo separation.

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Sat 12 Apr 2014, 09:09:29
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Post Re: Dolby Surround games; primitive surround sound on SNES
Caedhros wrote:
The SNES games, and later N64 and Gamecube games that support surround are just stereo signals designed to be processed by Dolby ProLogic surround. Just set your receiver to that and you're good to go.


My Denon UAVC-300 can decode ProLogic II in two flavors: Cinema / Music. It also auto-detects Dolby Digital, DTS, Stereo, and has another mode called "5ch ST" which does not seem to support auto-detection. I have pulseaudio set to pass-through DTS & AC3 encoding, which usually works with the auto-detection (as Dolby Digital).

I'm not sure from a technical standpoint what "5ch ST" means; It's not surround, just expanded stereo of some kind. I suspect it's a bult-in, hardware remap of a stereo signal to Center (50%R,50%L), R, RR(Expanded R), L, RL(Expanded L), because it works with everything; on the other hand manually setting the mode to various Dolby encodings can produce mute or single-channel sound for plain stereo.

I tried manually setting the receiver to ProLogic Cinema and Music for Jurassic Park, but this only produced thin, almost inaudible L and R and mostly Center audio.

EDIT: I may have been wrong about the autodetection; neither ProLogic mode seems autodetectable.


quequotion


Wed 16 Apr 2014, 06:03:41

Joined: Thu 02 Jun 2011, 01:36:41

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Post Re: Dolby Surround games; primitive surround sound on SNES
5ch ST is essentially what you described, it takes a stereo source and just spreads it over all 5 speakers without trying to make any surround effect. That's generally a manual setting on a receiver.

The Cinema/Music settings for ProLogic 2 is another manual setting. It just changes a few settings in the processing for what the listener prefers. I've never tried Jurassic Park on my system, so I'm not sure how well it used surround, but if you have a Gamecube and Rogue Squadron 2, it has a test mode for surround that works fairly nice.

On a semi related note, if you have DTS Neo6 support on your receiver, you can try it too, it's another matrix decoder like ProLogic.

Wed 16 Apr 2014, 23:51:41

Joined: Wed 06 May 2009, 04:13:19

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Post Re: Dolby Surround games; primitive surround sound on SNES
That's one thing I was never clear on with our surround amp.
I got the impression it couldn't auto-detect analog surround input and had to be manually forced into ProLogic mode instead of "upconversion" mode.
Which makes some degree of sense given the complete lack of capability signalling in the dual phono plug audio standard.
Certainly, it can autodetect surround in digital streams. That's easy. But analog is more challenging.

My further impression was cinema and music were like 5-channel stereo, only with different splits, and only when set to PLII mode did you actually get analog surround.

But the manual was EXTREMELY vague on the topic, so I was never SURE. And apparently never felt ambitious enough to experiment. I think the question only ever came up when I was itching to play a game or watch a movie.

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Thu 17 Apr 2014, 02:23:35

Joined: Thu 02 Jun 2011, 01:36:41

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Post Re: Dolby Surround games; primitive surround sound on SNES
ProLogic evolved into ProLogic 2, with cinema and music modes. Both are surround, but cinema tries to do more of a movie style surround mix, music mode is more subtle.

And yes, they can't detect formats over analog, but many receivers let you setup a default listening mode for each input.

Thu 17 Apr 2014, 12:41:32

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Post Re: Dolby Surround games; primitive surround sound on SNES
Caedhros wrote:
ProLogic evolved into ProLogic 2, with cinema and music modes. Both are surround, but cinema tries to do more of a movie style surround mix, music mode is more subtle.

And yes, they can't detect formats over analog, but many receivers let you setup a default listening mode for each input.

My receiver has movie, music, AND ProLogic II modes. All poorly-defined in the manual.
Which... doesn't make any sense by the mini-spec that I just dug out, which says it should be movie, music, and ProLogic(no numeral). But whatever.

It also has limited inputs.
To make a long story short, it was a home theater in a box setup with integrated DVD player, so they saw little need to include many inputs. It's not the best system in the world by a long shot, but it's the only PLII/digital surround setup I have access to.
Only thing I'm sure on with it as far as analog surround goes is that rear channels worked with PN03, and proved invaluable in some rooms.



Incidentally, the difference between movie and music modes is defined in the minispec.
Music mode reduces the surround delay so that the rear channels arrive at the listener at the same time as the front, whereas movie mode has a 10 ms delay, and applies a slight shelf filter to the surrounds.
Music mode also disables the "autobalance" feature, under the stated reason that singers are often placed offcenter in the sound stage intentionally, and autobalance would shift them inappropriately.
And enables a few optional filter controls(should the manufacturer choose to expose them on their amp) that aren't available in movie mode. The argument being that since music is not, as a general rule, mastered for >2-channel audio, some configurability of the matrix was needed to make it sound right.

Basically, movie mode is intended for sources mastered in surround, music mode is intended for stereo sources.
And ProLogic mode is, as the name implies, intended for accurate reproduction of older analog surround sources, with bandwidth-limited mono surround.



Moral of the story: For Althena's sake, include a comprehensive manual with your products!

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Thu 17 Apr 2014, 15:52:17

Joined: Thu 02 Jun 2011, 01:36:41

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Post Re: Dolby Surround games; primitive surround sound on SNES
My old receiver was an Integra dtr-7.2, on that if you selected prologic 2 it would always operate as either cinema or music mode depending on how you setup the pl2 settings.

And that's entirely separate from the various dsp modes available, and not part of the thx processing modes it had also.

Thu 17 Apr 2014, 17:47:29
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Post Re: Dolby Surround games; primitive surround sound on SNES
We need an SNES Dolby Surround test rom.

Fri 18 Apr 2014, 16:51:35
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