Forza Motorsport 4 - General Discussion

[Griffith500]

I would guess your supersampling/interpolation and the customary low pass filter are in response to the audio system update rate being asynchronous and at a different rate to your input sub-system. I would imagine T10 would have addressed that fundamental issue as a matter of course? Or am I reading you incorrectly?

My "input sub-system" is at audio rate, so yes.

The biggest issue I hear in FM that stands out above all else is the quantisation issue due to them presumably only being able to hold a finite number of discrete samples. Since engine note depends on RPM and Load as the main factors, they don't just use a simple single engine note that is pitch shifted for any RPM, but a set of samples according to load and some intermediary RPM values, and pitch shift from those. The reason I summise this, is you hear distinct quantisation issues when they suddenly switch from one base sample to another as a 'value' is crossed. it doesn't appear to be due to any update rate issues, just the inevitable simplistic quantisation, something that needs to be carefully blended around transitions, but can be quite processor intensive to do.
??

It's only a touch more complex than that. There are only two "banks" of sounds: on-load and off-load. A given pair of on/off-load samples are blended per sample point along the rpm scale (I don't know how many they use, maybe four - times two: 8 - plus idle, probably). The resulting blends are then, presumably, blended again (rather than blankly switched) according to the rpm level relative to the sample points - this switching is ideally done when one bank is silent, in my experience, even if you can do it inside of an audio "tick".
What you're hearing is possibly "quantisation" artifacts, but more likely aliasing due to the "slow" updating of the variables (again, Nyquist) that control these blends, as well as controlling the rate at which the samples are "read off" from the buffers for the varying rpm. Grand Prix Legends has quantising artifacts (low-precision volume representation), but is (as far as is audibly detectable) bereft of aliasing artifacts.

Anyway, the aliasing is because the audio controls are only updated every (graphical) frame, as per tradition. So early FM games had 30 Hz controls, later ones 60 Hz. This would explain the difference in incidence of the artifacts between the two sets of games. It also explains why it is so prevalent on the PC when they cannot render the graphics fast enough (watch a few user-made Shift videos on the toobs, you'll soon get the picture!) GPL's sound is decoupled from the graphics (well, they run at different rates, driven by the same internal clock, so graphical slowdowns don't audibly affect it except in the extreme), because most hardware at the time struggled to run it at audibly-acceptable frame-rates. iRacing seems to have inherited this trait.

What gets me is the control variables are all coming from the physics engine, which is already decoupled from the frame-rate. Why don't more (racing) games do that with the sound engine? It'd only need to be for the cars, and it'd make a massive difference. Do this and retain FM2's sound design, and I think FM4 would be set (for my tastes... which really means I needn't have written anything, because people will latch onto this and use it to justify not even bothering to take on board the point of view. Hey-ho.)

@ Mr. Latte: I was only joking, I apologise. That was just the kind of counter-argument we see against GT5. And you're definitely right. I'm holding on to the hope that the marketing media so far is aimed at portable devices, as that video doesn't sound quite so objectionable on my laptop speakers
EDIT: I know of Bangor, but mostly because of this. And a friend's terrible puns...

@ Hotspitta: To answer that, I would derail this thread even more. Short answer: no game is the "best". There are games that do different things well, some games that don't. Others are focused on other things.
I like FM2, PGR4 and some of the SimBin games for their samples and level of audio detail (like the gravel, rattles creaks etc. Shift inherited, that Mr. Latte mentioned) whilst I like LFS and GT5's admirable efforts to push the technology so that the artists get a better place to work. There is no progress without a struggle.

@ Spag: If you find Doctor Who "difficult", you should try real science. It'd probably make more sense!

 

[phil-t]

My "input sub-system" is at audio rate, so yes.



It's only a touch more complex than that. There are only two "banks" of sounds: on-load and off-load. A given pair of on/off-load samples are blended per sample point along the rpm scale (I don't know how many they use, maybe four - times two: 8 - plus idle, probably). The resulting blends are then, presumably, blended again (rather than blankly switched) according to the rpm level relative to the sample points - this switching is ideally done when one bank is silent, in my experience, even if you can do it inside of an audio "tick".
What you're hearing is possibly "quantisation" artifacts, but more likely aliasing due to the "slow" updating of the variables (again, Nyquist) that control these blends, as well as controlling the rate at which the samples are "read off" from the buffers for the varying rpm. Grand Prix Legends has quantising artifacts (low-precision volume representation), but is (as far as is audibly detectable) bereft of aliasing artifacts.

Anyway, the aliasing is because the audio controls are only updated every (graphical) frame, as per tradition. So early FM games had 30 Hz controls, later ones 60 Hz. This would explain the difference in incidence of the artifacts between the two sets of games. It also explains why it is so prevalent on the PC when they cannot render the graphics fast enough (watch a few user-made Shift videos on the toobs, you'll soon get the picture!) GPL's sound is decoupled from the graphics (well, they run at different rates, driven by the same internal clock, so graphical slowdowns don't audibly affect it except in the extreme), because most hardware at the time struggled to run it at audibly-acceptable frame-rates. iRacing seems to have inherited this trait.

What gets me is the control variables are all coming from the physics engine, which is already decoupled from the frame-rate. Why don't more (racing) games do that with the sound engine? It'd only need to be for the cars, and it'd make a massive difference. Do this and retain FM2's sound design, and I think FM4 would be set (for my tastes... which really means I needn't have written anything, because people will latch onto this and use it to justify not even bothering to take on board the point of view. Hey-ho.)

As an engineer, it makes zero sense to assume audio is tied to frame update, especially as that can be so variable at times. Surely, as logic dictates and you have mentioned, it would be driven from the physics engine.

With that in mind, are you an industry insider with this intimate knowledge, or just basing all this on your own experience of the field of audio engineering? or just blagging it?

It's hard to not just look at a wall of illogical text (you never know, you might be right on the button) and think 'hot-air', but in this day and age, you never know who is lurking on forums.. so please tell us..

 

[HBK]

Griffith500 is posting some very interesting insight

Edit :

It's hard to not just look at a wall of illogical text (you never know, you might be right on the button) and think 'hot-air', but in this day and age, you never know who is lurking on forums.. so please tell us..

His posts are very logical and I think most of his reasoning likely corresponds to what happens in racing games right now.

 

[cuco33]

Don't want to get into the whole technical discussion on audio... but to me if it sounds great then I'm all for it. In Forza a VTEC equipped Honda sounds like one, even when VTEC kicks in at the higher RPM. A VW VR6 motor has that VR snarl that the engine is infamous for. The list goes on and Forza series to me does such a better job at sounding like the real cars than most games. To me GT series, aside from maybe a few handfuls, doesn't sound like the real cars. It's sad that some arcade games sound better than those recognized as the sim games. I hope FM4 continues to improve the sound samples for these engines. They probably won't be 100% perfect though and I'm fine with it as long as it sounds like the real thing.

 

[Griffith500]

As an engineer, it makes zero sense to assume audio is tied to frame update, especially as that can be so variable at times. Surely, as logic dictates and you have mentioned, it would be driven from the physics engine.

With that in mind, are you an industry insider with this intimate knowledge, or just basing all this on your own experience of the field of audio engineering? or just blagging it?

It's hard to not just look at a wall of illogical text (you never know, you might be right on the button) and think 'hot-air', but in this day and age, you never know who is lurking on forums.. so please tell us..

Do you know this, or are you positing an opinion based on some experiences you've had somewhere or other...??

 

[phil-t]

Do you know this, or are you positing an opinion based on some experiences you've had somewhere or other...??

No, it's common sense.. I wasn't stating a fact, I was postulating that tying audio update to frame rate when the key audio input parameters are all generated by a much faster physics engine makes absolutely no sense at all on any engineering level..

Hence why I'm interested in knowing of your exact experience in racing game audio development, when something flies in the face of common sense on this scale, either you know for a fact this is the case, in which case, I'm genuinely surprised, and happy to be taught something new, or you are just hypothesising wildly, in which case, I am very sceptical of what you are saying.

It's as simple as that really.

 

[Spagetti69]

Sounds great to me.

 

[Griffith500]

No, it's common sense.. I wasn't stating a fact, I was postulating that tying audio update to frame rate when the key audio input parameters are all generated by a much faster physics engine makes absolutely no sense at all on any engineering level..

Hence why I'm interested in knowing of your exact experience in racing game audio development, when something flies in the face of common sense on this scale, either you know for a fact this is the case, in which case, I'm genuinely surprised, and happy to be taught something new, or you are just hypothesising wildly, in which case, I am very sceptical of what you are saying.

It's as simple as that really.

Which is what I was saying - although "common sense" is a stretch, obviously. In terms of game development, it was the way once upon a time, that everything was updated in a game engine's "tick" function at once: graphics, sound, logic - everything. Of course, the lowest common denominator is the graphics - why update any faster than the game can give you new information? In most cases, I doubt that 30 - 60 Hz is too slow, but in racing games it really is, to my ears.

I have used FMod Designer, which is a common sound tool in the industry that can be used to make engine sounds. I don't know specifically at what rate it "updates", but it has the same aliasing issues I've discussed. You can try it for yourself. FMod is free (for non-commercial use), and here are some examples.

I'll also refer you to this document (sorry, it's a .pdf, but it's the best I can do in the time) page 4, towards the end of the first paragraph. It's written by Leonard J. Paul.

I have personally experienced the temporal aliasing all the way down to the 16 ms update interval in the UDP-based "OutGauge" system in LFS, beyond which I had to resort to signal alteration, as mentioned already. Oddly, I never thought to disable v-sync...


Sorry for killing the thread

 

[Bogie 19th]

Forza 4 Hands On Preview:

Turn 10’s latest installment of Forza Motorsport was formally announced at last year’s E3 and has slowly been gathering pace as racing fans count down the days to October 14, the game’s official release date in Europe. Metro was invited down to the Top Gear test track at Dunsfold for a hands-on preview of a host of the game’s new features.

While we weren’t able to get any time on the ever-popular multiplayer modes we did manage to take a handful of cars for a spin round the virtual Top Gear track as well as the much-hyped ‘Alps’ circuit, the focal point of the initial teaser trailer released last month.

First impressions are that the series hasn’t lost any of its gritty attention to detail, a fact that’s sure to impress the legions of hardcore racers and tuners. Cars on offer at the test day included the Ferrari 599 GTO, a 2011 WRX-spec Impreza, the Cougar Eliminator and the star of Top Gear’s ‘Star in a reasonably priced car’ segment, the Kia C’eed.

Each behaved as you would expect, the Ferrari providing wonderful grip and speed, before turning into a snarling monster as soon as you dared to turn off the traction control and abs. The Cougar Eliminator provided the complete opposite, wallowing slowly from side to side around the tight and twisty Alpine raceway.

Turn 10 is yet to announce the full car list, but based on previous efforts we’d assume that it’ll be fairly comprehensive with something on offer to suit every kind of driver.

Much has been made by Turn 10 of the new image-based lighting model that has been employed for Forza 4, an effort to create more realistic-looking cars and racing environments. On tracks such as the Alps the engine comes to life, with sunlight bouncing around between snow-capped hilltops. The effect becomes even more impressive once you hit a tunnel or forest section, sunlight flashing between trees and unsettling your view of the track.

Turn 10’s Brian Ekberg told GameCentral ‘Because the car is lit from all points, it also allows us to play around with time of day.

‘So in some events you’ll see a track that is in daylight in a two heat race and in the second heat you’ll be racing in the afternoon, the late evening.’

Whether these changes will make it over to multiplayer mode remains unsure, but the feature should add a new aspect to the single-player mode at very least.

Ekberg also confirmed that the Alpine track would be players’ very first taste of Forza 4, adding ‘We wanted to make sure that this was really fast, really fun and as visually impressive as we could make it’.

As for the single player racing the computer-controlled cars appeared suitably aggressive, particularly when the difficulty was notched up, moving across to cover the inside line into corners and pushing you out to the edges of the track when battling for position.

However, the artificial intelligence is not without its flaws, with a number of opponents seemingly unable to hook up a reasonable start from the grid allowing you to quickly bag a couple of places in the run down to the first corner.

Forza 4’s new tie-in with Top Gear has been widely publicised and fans of the show are no doubt itching to begin testing their mettle in the Kia C’eed, attempting to beat the likes of Rowan Atkinson and John Bishop round the famous test circuit.

We're happy to report that the track itself sticks rigidly to the classic layout, recreating the many features of the Dunsfold Aerodrome, from the Top Gear studios to the famous jumbo jet – though anyone wishing to explore the area will be disappointed as any attempt to stray too far from the tarmac results in an immediate re-set of the car.

GameCentral was lucky enough to be allowed out in the C’eed for a hot lap around the circuit and can report that the in-game track features the same bumps, lumps and surface changes as the real thing, so racers should be able to compare their times to those of the stars.

While we were a couple of seconds slower round the track in real life than in-game, we’ll put this hesitation down to the lack of a rewind feature and possible bodily harm if we crashed in real-life, rather than any inherent problems with the car and track modelling in Forza 4.

Turn 10 have also been busy with the multiplayer elements of the game, revealing that Forza 4 will again feature Car Clubs, where members will be able to share garages and skills such as tuning, painting and of course driving will be rewarded.

The racing itself will feature up to 16 cars on-track at any time and a variety of modes, including the Top Gear-inspired car football and car bowling modes.

A result of the unofficial car football games that occasionally cropped up online, the new modes at least look set to provide a short-lived distraction from the classic race modes.

Autovista is another new feature for Forza 4, a Kinect-powered virtual garage where players can explore and learn about a host of exotic metal. The mode is only set to feature a select few cars with many featuring narration from Top Gear’s very own Jeremy Clarkson.

While impressive in terms of detail, the mode does suffer from occasional moments of awkwardness inherent in many Kinect games, such as waving your hand around inanely in order to open a car door.

Kinect is also set to play an important part on track with head-tracking enabling racers to slowly look into the apex of a turn, either by turning their head or tilting from side-to-side.

In a nod to the ever-popular casual gaming market, players will also be able to control the game with a virtual ‘wheel’, while the game takes care of acceleration and gaming.

It’s doubtful whether anyone will actually use the feature throughout the game, but it remains a neat trick to entice those scared off by the idea of simulation racing.

Forza 4 is sure please fans of the series by tweaking the tried-and-tested formula and providing one of the most realistic driving experiences around. New features such as Kinect integration and the utterly unsubtle Top Gear tie-in may keep casual players interested for longer, but the focus remains on the cars and tracks, which should see Forza 4 ruling the racing roost for years to come.

Read more: http://www.metro.co.uk/tech/games/8...-gamecentral-takes-to-the-track#ixzz1TzpfjRIS

Not really much new, just more confirmed.

 

[phil-t]

Which is what I was saying - although "common sense" is a stretch, obviously. In terms of game development, it was the way once upon a time, that everything was updated in a game engine's "tick" function at once: graphics, sound, logic - everything. Of course, the lowest common denominator is the graphics - why update any faster than the game can give you new information? In most cases, I doubt that 30 - 60 Hz is too slow, but in racing games it really is, to my ears.

that is such an ancient design paradigm, and we already know FM uses an asynchronous physics engine running at 360Hz, I still can't see any real evidence that shows audio is tied to framerate in these situations.

I have used FMod Designer, which is a common sound tool in the industry that can be used to make engine sounds. I don't know specifically at what rate it "updates", but it has the same aliasing issues I've discussed. You can try it for yourself. FMod is free (for non-commercial use), and here are some examples.

I'll also refer you to this document (sorry, it's a .pdf, but it's the best I can do in the time) page 4, towards the end of the first paragraph. It's written by Leonard J. Paul.

Reading the FMod and Sonory sites, the engine audio synthesis they show being used in FMod Designer is fully artifcial, it even states it's to save issues with dyno sounds polluting real world samples, since FM uses real world samples, it's safe to say they aren't using Sonory for example, it sounds like they have their own custom solution, or just a standard one we aren't privvy too.?

I have personally experienced the temporal aliasing all the way down to the 16 ms update interval in the UDP-based "OutGauge" system in LFS, beyond which I had to resort to signal alteration, as mentioned already. Oddly, I never thought to disable v-sync...

or even running your audio update engine asynchronously at a stable higher frequency?

Sorry for killing the thread

It's marginally technical, and we are in a lull at the moment, awaiting new info, so I guess we can carry on..

Someone did raise a good point above, the pops and crackles are a known artefact that where admitted by a T10 engineer as being due to processing loading issues, not framerate, this does indicate that their audio is asynchronous to the frame rate, but is certainly far from perfect?

 

[Spagetti69]

Nice find bogie.

Wonder how far we can go off before the car re-sets to track.
Seen a video with a car seemingly miles off.

 

[theotherspongey]

Is it confirmed if we have the entire top gear track? Not just the figure 8?

 

[HBK]

Someone did raise a good point above, the pops and crackles are a known artefact that where admitted by a T10 engineer as being due to processing loading issues, not framerate, this does indicate that their audio is asynchronous to the frame rate, but is certainly far from perfect?

If I remember right, this engineer said that the onboard sound processor could sometimes be overloaded with too many samples, thus the pop and crackles as some samples would abruptly override other ones.

It is most likely a hardware limitation (a limitation that is not perfectly handled by the software), rather than a strict issue regarding synchronization.

 

[Griffith500]

that is such an ancient design paradigm, and we already know FM uses an asynchronous physics engine running at 360Hz, I still can't see any real evidence that shows audio is tied to framerate in these situations.

That's what I've been saying.
So, you heard the artifacts, thought they were due to quantisation or table swapping, but now it's fine?

Reading the FMod and Sonory sites, the engine audio synthesis they show being used in FMod Designer is fully artifcial, it even states it's to save issues with dyno sounds polluting real world samples, since FM uses real world samples, it's safe to say they aren't using Sonory for example, it sounds like they have their own custom solution, or just a standard one we aren't privvy too.?

I never said Forza was using Sonory's system, which is direct, offline synthesis. I pointed you that way for the Fmod Designer examples. Fmod Designer includes a sample blender for car engine sounds in the currently popular configuration, as I described in a previous post. Sonory synthesised the samples and played them back in Fmod as an example of how their workflow can be integrated directly into Fmod, one of the more popular audio middleware tools - it's marketing. Forza 3 uses Fmod, it's on their list of "popular games that use Fmod".

My tests with Fmod Designer showed the same artifacts I've been talking about. The paper I linked to states the Fmod user documentation recommends trying higher audio control rates than the typical 16 ms in 60 fps games for granular synthesis, where sounds are very short - i.e. rapid changes.

or even running your audio update engine asynchronously at a stable higher frequency?

It runs at 96 kHz.

It's marginally technical, and we are in a lull at the moment, awaiting new info, so I guess we can carry on..

Someone did raise a good point above, the pops and crackles are a known artefact that where admitted by a T10 engineer as being due to processing loading issues, not framerate, this does indicate that their audio is asynchronous to the frame rate, but is certainly far from perfect?

That's a rather blaze hypothesis, wouldn't you say?
To add to what HBK said, the XBox 360 does all its sound processing on the CPU, so sound is competing for floating point, parallel throughput with graphics, AI and physics. Graphics and physics will "win", so if too many samplers are left active, they'll get chopped; if new ones suddenly come into being, they'll override quieter ones, ideally without audible incident - remember how I mentioned swapping sample buffers whilst the output was silent? This sounds more to do with the management of buffers to me.
I haven't heard these pops or crackles, as far as I know, however.

 

[Mr Latte]

Gees would you two please go to PM or go create your own thread as your chatter is way off general FM4 discussions or much interest to most that would read this thread.

This isn't the place for it and to be fair you have had plenty of talk already on the subject guys.

 

[HBK]

My bad, I thought the 360 had it's own sound processor

Thanks for the heads-up.

Anyway, if you want to hear pops and crackles, go into a slide on the last turn of Sebring. You'll hear them.

They are also very frequent on Positano, and somewhat frequent on Catalunya. They seem to be much more frequent on some tracks surfaces, probably due to the way they are modeled.

 

[Mr Latte]

Latest Week In Review News
Here

"World Tour gives you an option to choose between several race events, each offering a variety of awards. At the end of each season, as John mentions in the video, you’ll have compete in a two-heat championship race, one taking place in the morning, and the other heat in the afternoon—just like many racing events in real life. The video also shows off the game’s fantastic new lighting engine and 12-car World Tour racing"

"How does the Escort Cosworth stack up against the Subaru Impreza 22B
For location, we chose the TopGear Test Track Drag ¼-mile strip, one of the new track environments in Forza 4, and an appropriate location for such an outlandish shootout. One by one, Fred hustled off the line in each car, and after twenty runs, the results were surprising."

 

[jabofu]

Latest Week In Review News
Here

"World Tour gives you an option to choose between several race events, each offering a variety of awards. At the end of each season, as John mentions in the video, you’ll have compete in a two-heat championship race, one taking place in the morning, and the other heat in the afternoon—just like many racing events in real life. The video also shows off the game’s fantastic new lighting engine and 12-car World Tour racing"

"How does the Escort Cosworth stack up against the Subaru Impreza 22B
For location, we chose the TopGear Test Track Drag ¼-mile strip, one of the new track environments in Forza 4, and an appropriate location for such an outlandish shootout. One by one, Fred hustled off the line in each car, and after twenty runs, the results were surprising."

I predict that there will be a Top Gear Track Drag 1/2 mile and one full mile besides the quarter mile. The locations in FM3 that support the full lenght all have those tiers.

 

[Mr Latte]

Will be nice though at the Top Gear track something you'd of thought GT5 would of included.
Now I wonder if they will allow 16 player drag races online?

 

[theotherspongey]

Will they have something similar to GT5 where you can cruise around a track before a race starts?

 

[Bogie 19th]

If drag racing is back, then I hope it's substantially improved over FM3s drag racing.

 

[HBK]

Will they have something similar to GT5 where you can cruise around a track before a race starts?

Unlikely.

 

[Bogie 19th]

That would be nice if they did. You can do that in Race Pro as well.

 

[Griffith500]

Will they have something similar to GT5 where you can cruise around a track before a race starts?

Unlikely.

That would be nice if they did. You can do that in Race Pro as well.

Are we talking about a practice session? Why is this unlikely?

 

[theotherspongey]

Are we talking about a practice session? Why is this unlikely?

Because it wasn't in FM3 I guess...

 

[Bogie 19th]

They already confirmed we will not have qualifying either, which sucks.

 

[Eunos_Cosmo]

The best part about T10 is that they seem to sift through this site (and many others like it I'm sure) and pick up on criticism of GT5 and figure a way to implement 'better ways' of doing things into Forza. Whereas PD seems perfectly content to just go about it their own way. I suppose both are admirable in their own way.

 

[HBK]

Are we talking about a practice session? Why is this unlikely?

It depends.

Offline, I don't think that will be the case, but that is a definitely possibility, albeit not a very useful one.

Online, I would be tempted to say "not gonna happen". Too much hassle on so many levels.

 

[Hotspitta]

Lets Discuss

 

[Bogie 19th]

Dude, I made a thread for that video, and now you have posted it in two other threads wanting to discuss it?

How about discussing it in it's original thread?