Interview: The Logic Behind Rogue Leader
Factor 5 explains what it means to play Rogue Leader in Dolby Pro Logic II. Click here.
September 27, 2001
Now you know it -- Star Wars Rogue Leader: Rogue Squadron II will be the first videogame ever to support 5.1 Surround Sound with Dolby Pro Logic II. We recently had the chance to experience the game in DPLII and we can tell you that it's nothing short of awesome.
After our ears had stopped ringing and our eyes returned back to their normal positions in their sockets, we chatted with Factor 5's president Julian Eggebrecht and company programming guru Thomas Engel about what it means for gamers to play Rogue Leader in Pro Logic II. Following is our interview:
IGNcube: What is Dolby Pro Logic II and what does it mean to GameCube owners who buy Rogue Leader?
Julian Eggebrecht: Dolby Pro Logic II is a new technology from Dolby Labs which allows us via a proprietary encoder which we developed to have full positional five-channel sound in real-time for Rogue Leader. DPLII was originally developed as a supplement to DD to get more out of old Stereo and Dolby Surround material and it does a remarkable job with it, but we are taking it to a completely new level.
Dolby was nice enough to give us an early prototype DPLII decoder and we set out to find a way to get full positional audio going - something not even Dolby expected to be possible. This, combined with the fact that DPLII has no latency, no compression, the full frequency range on all five channels, works with existing cables, and is even backwards compatible with stereo and surround equipment makes it the perfect five-channel audio system for games.
IGNcube: How does the technology work?
Thomas Engel: You use the regular stereo-cable for your GameCube. If you have a stereo setup, you will hear very nice stereo effects with a bit of additional spatial positioning going on. If you have a Pro Logic receiver, you will get very good real-time 4 channel surround sound with the old DPL drawbacks of reduced frequencies in the back and very limited channel separation.
Factor 5's technical wizard Thomas Engel
If you have a receiver that has DPLII, you switch it to the DPLII movie mode and you play Rogue Leader in full five-channel audio (stereo surrounds) with extremely accurate channel separation, the extra oomph via a subwoofer and all the other features. The technology is great because it is so easy and transparent to use. No extra cables or settings involved - a very, very clean solution for games. And of course there are no tricks: All sound effects in the game are encoded in real-time in full 3D, so if a Tie zooms by behind you it does that in the rear surrounds just as you are used to from good cinema five-channel setups. We have no channel limitation for 3D voices so all channels the audio uses are full 3D channels.
In the cockpit for example, we have a whole different set of sounds. We have instrumentation going on, blips, R2D2 sounds, different voice sounds, different laser sounds, and more.
Julian: Yes, it's very neat. We're using a lot of memory for the sounds and with the huge amount of A-RAM that GameCube has most of the sound effects are at very high rates -- they're usually twice as high as we would have ever done them on N64, probably even three times.
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IGNcube: Will Rogue Leader be the first game to use Dolby Pro Logic II sound on GameCube?
Julian: Rogue Leader is the first game on any platform to use DPLII. We were lucky because Dolby gave us the prototype hardware really early on. The first consumer units for other developers are only becoming available now, and we had the hardware much earlier because we have a history going back with Dolby. So we read about the technology, contacted them about it and they offered us one of their prototype units which was really nice because they only had two or three of them at the time. They said, "Here, take it -- and see what you can do with it." And it worked out quite nice.
IGNcube: Based on your own experience in listening to Dolby Digital and Dolby Pro Logic II, how big of a difference do you really think there is?
Julian: For movies if you do a specific mix with the discreet stuff, of course you can do things in Dolby Digital which you simply cannot get in terms of channel separation here because it is even cleaner. But for real-time applications there are other things to consider. First of all, to encode Dolby Pro Logic II is 10 times easier [than Dolby Digital] in terms of mixing it and doing it in general. With the games industry, being relatively far behind in terms of sound technology, I think we're going to hear a larger amount of bad Dolby Digital mixes simply because people are not accustomed to it. I mean, it's comparable to the first movies in Dolby Digital were a few -- like Cameron's movies and Dracula from Coppola -- that were very nicely mixed. But there were also many others that completely didn't get how discreet mixing works.
Since this DPLII technology is being implemented for use with our artists, and basically also for the sound designers, in-engine you can't do too much wrong -- that's the cool thing and I think the games will profit from it.
Thomas: It's a very smooth migration.
Julian: For the regular person out there who has a typical $2,000-3,000 home theater setup, I don't think they're going to hear the difference between our Dolby Pro Logic II real-time and Dolby Digital.
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IGNcube: It actually drops down to work with regular Dolby Pro Logic?
Thomas: Yes. It also works fine on regular Stereo equipment.
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IGNcube: Is there any extra hit on the GameCube's processor for doing DPLII versus regular Pro Logic?
Julian: You wouldn't notice it since the performance is taken from the DSP and we have a very elaborate load management system running for the DSP anyway. Our spec of 64 3D voices didn't change due to DPLII.
Julian: We're definitely going to have a little demo in Rogue Leader -- a cut-scene we can play in the special features area of the game where you just have a Tie going around, and the sound separates to different channels.
IGNcube: Tell us about Dolby Digital latency issues.
Thomas: Well, you need some time to compress your samples and this leads to the latency problems with real-time Dolby Digital. Basically, you have the same thing in DVD movies, but it doesn't harm you there because you know what the latency is, you know what will happen in the next five minutes because Harrison Ford is always going to use the blaster to shoot down the Storm Troopers. In a videogame the player isn't predictable. So, you have to know in advance and you can't without prophecy -- so you get latency due to the compression time.
Julian: Dolby is right when they say that they're real-time encoding is relatively low, but nevertheless it's there. It's anywhere between 50ms and 100ms. 50ms is barely okay, but 100ms for a game like Rogue Leader is unacceptable. So for non-action games I don't debate that the issue is moot because if you're not rapidly shooting you might not need that fast feedback. But if you're shooting lasers, especially for a game running at 60 frames per second, the latency is a huge problem. When we were testing around with triple-buffering, our audio was initially quite a bit off due to bugs and you immediately noticed it with the shooting. So for action games, you really need to have no latency -- it's a big thing, it really is.
Thomas: In Rogue Leader the thing that you look most at is your own craft, and it isn't terribly far away. In the distance, if a canon fires a shot and the sound lags behind, that might be realistic. But if a laser blast goes directly in front of your ship, you cannot have the sound lagging behind due to latency. It should have a big "boom" immediately.
IGNcube: How good is Rogue Leader's bass separation using Dolby Pro Logic II? How does it compare to true discrete 5.1 bass such as Dolby Digital and DTS?
Julian: Just as good as the general channel separation. Once again, comparing it to DD and DTS, it sounds almost the same and most people probably wouldn't hear a difference.
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In general, every single sound in the game is in surround since all of them are positioned with the 3D API.
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