TV camera improvements

Yea yea, I know there are more important things, but I think there is much to be improved with the TV cams. Especially if AC is be taken more seriously in e-sports in the future (*cough* well-working driver swaps *cough* pit limiter *cough* spectator mode *cough*). AC is such a great looking sim and I think it should be exploited more. I love messing around to create some nice TV cams but I often run into the limitations.

Specifically 3 things.

FOV gamma
Right now there's an FOV gamma setting in the tv camera file (cameras.ini) which doesn't work that well. To explain. There are 3 parameters for the FOV atm:
MIN_FOV
MAX_FOV
FOV_GAMMA

Minimum is the point where the car is the furthest from the camera, maximum where the car is the closest. And then gamma, which dictates the gamma when moving from min to max. A low value (say 0.1) keeps closer to the minimum value for a longer time and a high value (1.0) is (I think) linear. The problem is that this doesn't work in reality.

At gamma 1.0: imagine the car being 100m away driving past at 10m. If the FOV is 1 degree at 100m and 10 at 10m, then at 90m the FOV would be 2 degrees, at 80m 3 degrees, etc. But at 50m the FOV would be 5 degrees.

But at 50m, the car is twice as close, so the FOV should be 2 degrees at 50m, 4 degrees at 75m, etc.

It would be great if the gamma at 1.0 would be squared like that instead of linear. A higher gamma (up to 2.0) would make the camera then zoom out faster in the beginning and a lower value would mean slower zooming when the car is far away.

To illustrate:
TV cam with the FOV gamma at 1.0
TV cam with the FOV gamma at 0.5
TV cam with the FOV gamma at 0.1

Notice how quickly the camera zooms out at 1.0. At 0.1 it follows the car very nicely and keeps it about the same size in the screen up until it starts to go over the crest. Suddenly the car fills up the whole screen and and for a few meters when the car is closest it suddenly jumps to the max fov (12) and then back. At 0.5 the jump is gone but it still zooms out too quickly.

Movement
Whenever the camera is zoomed way in (FOV of 1 or lower) it's horrible to watch. The camera is swaying to all sides like the cameraman is drunk:
https://streamable.com/6sin6

Then when the car drives past it's very stable.

Compare that to the same shot from a real race (at 20:58):


Notice how stable the camera is when the car is approaching. Only when the car drives past you can see the camera start to sway, while trying to keep the car on screen.
Changing cars
Not quite as big of a deal to me, but it deserves mentioning. In Assetto Corsa, when you change the camera to view another car it quickly fades to black and then back to the other car. In reality this wouldn't happen of course as the camera would just pan from one car to another.


I think iRacing has the TV cams pretty much nailed in those 3 aspects. Notice how the car's size relative to the screen is pretty much the same in one shot. For the movement the camera is very stable when the car is driving towards it, but when the car drives past it sways a bit. I think it does this quite cleverly by having a bit of delay and then overcompensating:

From 1:54:


And as far as changing cars goes (at 0:26):

It doesn't fade or cut from one car to the other, but the camera itself pans, like you would do with a real camera.

 

On your first point, the FOV that creates a constant scale of the car is proportional to the inverse of the distance - so doubling the distance means halving the FOV, tripling the distance means a third the FOV, etc.

That means the correct gamma function is proportional to 1/x.

For example if you have 20 degrees at 50m, 10 degrees at 100m will make the car the same size.

I'm not sure exactly how the game calculates min/max FOVs' distances but the word gamma implies it's a function along the lines of (min_fov + (distance/max_distance)^gamma*(max_fov-min_fov). So you might want to try something along the lines of
MIN_FOV = 0
MAX_FOV = 4 (or whatever you want it at the farthest distance)
FOV_GAMMA = -1


To do it properly you'd probably want MIN_FOV and MAX_FOV to define the range the camera lens is capable of, and introduce a new parameter FOV_SCALE that multiplies the direct result of the 1/x. So eg. at FOV_SCALE=500, you'd have 500/100m = 5 degrees FOV at 100m, and then if that's smaller than MIN_FOV, adjust it.

 

To add some more. I was messing around with DOF and noticed that the focus is behind the car consistently when a car is far away: http://i.imgur.com/Ezd1rcW.png
Notice how the spectators are sharp but the car isn't. I tried (I think) all DOF related number in the cameras.ini and in the PP filter, but I couldn't fix it.

 

I would add that, when in VR, the camera doesn't move, as you just can move your head to see what you want, instead of rotating automatically when the car passes by. This should be something very quick to address.

 

I learned this from someone today: to remove or change the wobble change the settings in camera_track.ini, in the system/cfg folder.

 

That does it globally though. It would be better if it was a per camera setting.

One thing I would like to see is panning controls which allow the car to completely zip out of frame and then for the "camera" to catch up with it a split second later like a real camera might if it's a quick pan on a fast straight.