Problems with video overlays

[Harry]

Please note the video does not need to be in the camera roll. Any place in the Photo app is fine. One interesting observation has been that access to the Photo app is limited if Location Services are turned off. Please check this too.

Finally, acceleration treatment will be changed in v16, it has 30 Hz as default and can be tweaked as you like.

- Harry

[hms]

Hi Harry,

In regards to video overlays, on my iPhone 4 (using RAM motorcycle mount) I'm getting a very 'rippled' and shakey video. Do you have any recommendations for smoothing this out or is this an issue with the iPhones video recorder?

Regards,

Tom.

I'm not sure if the iphone has a CMOS sensor, but they suffer from an effect called rolling shutter.
See this:
http://en.wikipedia.org/wiki/Rolling_shutter

Must say i haven't experienced this yet.
H

[jmciver]

Supposedly it is an issue with the iPhone as I had the same problem.

[onemanracing]

Please note the video does not need to be in the camera roll. Any place in the Photo app is fine. One interesting observation has been that access to the Photo app is limited if Location Services are turned off. Please check this too.

Finally, acceleration treatment will be changed in v16, it has 30 Hz as default and can be tweaked as you like.

- Harry

As I was saying, I can't access anything but the camera roll and the app storage area. I can watch the movie from within the photo app but not access it from within the laptimer app.
Now, about the damping, I can't wait!
I know it's tricky, I also have a Racelogic DL1 and the G-sample is usually all over the place when logging in my racecar and needs some smoothing but not this much.

Regarding rolling shutter, just switch on the camera app and wait for the view to appear from the cam, then pan quickly right-left-right-left and watch the world wobble...
You need to get rid of the vibrations, a super rigid mount in a very heavy structure works best (for instance a steel mount bolted solidly into a roll cage) a weak mount on something that vibrates a lot (like a plastic mount on a bike handlebar) is terrible and it's much better to go for a soft, dampening mount like rubber (or a brake master cylinder resorvoir).
Around the update frequency of the cam is the worst frequence and it will create a floating watery effect that will make you motion sick.

[jmciver]

Well I used a RAM mount attached to the roll bar inside my car. The "balls" that are used in the RAM mounts are made of very hard rubber to help minimize vibration. I still had the "wobble" in my video although it seemed to occur mostly at speeds above 100 mph. Below is the video...

http://www.youtube.com/watch?v=c1I4s9r_prQ&sns=em

[onemanracing]

In my experience any rubber will make things worse, as stiff as possible is the way to go if you have access to a cage. "Short" mounts, as in as close to the cage as possible, and solid metal everywhere. Have had excellent results with home made mounts in steel bolted solid to the rollcage.

[Harry]

I have no chance to watch the video currently, so I might be wrong. Besides vibrations from the mount, there is a known effect from the iPhone4S's picture stabilization. In iOS5 it seem to not be possible to turn it off, in iOS6 it probably will be. So stay tuned.

- Harry

[fluppie00]

As Harry says, the 4S video stabilisation s**ks if you use it in car. It's only handy when holding it in your hands. I have a selfmade mount with 2 suction cups and a 6mm alu plate. Only this isn't good for the GPS reception ...
External GPS is recommended. Stil don't know if I'm going for the Emprum Ultimate GPS or the Dual XGPS 150. I think the Emprum because it's wired and my OBD receivers are both wireless (KiWi WiFi and GoPoint BT1).

[Chall392]

When I tested LT around home, everything worked fine....video overlay displayed TP and RPM, but when I tried it on the track(VIR), the gauges were there but indicated zero.

[Chall392]

I deleted sessions where the RPM and TP were zero so there is no way for mr to see if that data was whole. During the sessions subsequant to the above, I didn't capture video but the files show that RPM and TP were recorded.. Any idea why the overlay didn't work fullly?

Thanks