MXm, SCHD, RSA3.

When viewing 2 laps in RSA3, and in the Data-Movies layout (eg, looking at data and movies of 2 laps);
I assume when the plot-base x-axis is set to distance, that one of the videos time-base will get "expanded" or "shrunk" so that the car in both videos are very close to the same position (distance wise) on track? Do we know what the goal is of how close they should be? A few frames?

Maybe this is just the nature of trying to compare 2 events that happened at different times and different rates, and measured with multiple devices.
But I'm digging into analyzing a turn, comparing 2 laps, using videos, and the discrepancies between where the car is on track, and discrepancies between the data on the graph and in the SCHD display, make detailed comparison difficult. FYI, looking at the delta-T channel, it's obvious I lost about a 1/4 sec over a distance of about 200', so it's not a trivial event.

 

Yes, the X axis is distance (from s/f). RS3A uses what they call "super shrink" to break the lap into many little segments and then shrink and stretch those to keep the overall lap distance. This is different than most applications that shrink or stretch the entire lap. I use the data in RS3A over what is on the SCHD display. For fine detail of how it works, email software@aim-sportline.com and include screen shots of what you are seeing. They will answer and give you more detail that I can. There is a lot going on in the software and now to handles the position and info to do the synch.

I'm also happy to help you take a look at what is going on. Shoot me an email. The way that RS3A uses the GPS info is very, very different than RS2A and it can make the time compare look pretty different. We are so used to seeing the old time compare method that sometimes the new one looks very odd. I have seen this in the data and in the car using predictive on the SLM.

 

Yes, that’s tough, unless synced to position as opposed to clock and corrected distance base.

Wonder if it’s better if you just use the video? Or are you doing that now?

I assume you’re loading the data and the video?

 

Thanks guys.

After Matt's comment about slices, I remembered an AiM video on that topic and found it; RS3A beta update #2 has some details.

Peter, yes, I've loaded both the data and the videos, and viewing side by side.

Easy to get lost in the small differences; eg data trace might show 40mph, but SCHD view shows 42mph, for example. And view in the car is not perfectly synced, roughly 5-10' difference. Probably all within the margins of the equipment and software being used.

Bottom line, looking at delta-T showed me a problem, comparing the 2 vids side-by-side along with TPS on the vids, shows clearly I touch the gas too early and push the car out past the ideal line, gaining some time in the short term, and losing time down the straight. Pretty cool, and classic. This would be hard (for me) to see with just the data; the added video helps tremendously. This is all to create a little clip for an upcoming class I'm teaching, so I wanted to understand any discrepancies.

This data stuff is hard.

 

My question was whether if the video was synchronized differently (better or worse) if you loaded the video only into RS3A beta?

The measures lag on the video is usually due to the rendering lag. Pretty common in all three manufacturers that make that equipment.

 

If I understand your question correctly Peter, so far, I've only looked at the videos side by side as loaded into RSA3 and synced by RSA3, along with the data from an MXm. Are you saying, load the videos and data from the SCHD, but not the data file from the MXm?

 

Yes, that is what I am saying.

 

A little bit better. In low speed corner, 5' car position difference, and 1mph discrepancy between the graph view and the onscreen SCHD speed.

I sent AiM a feature enhancement request, it might be nice to have the # slices used to be user-settable when analyzing small sections. Assuming more slices would reduce the discrepancy. Understanding processing would take a hit. But sometimes, it might be the right trade off.

 

The details of the slices has changed some since then and it is even better.

The data that is included with the video is only at 6 Hz, versus 10 Hz GPS data. I would go off the MXm data in RS3A, not the video data.

 

Thanks Matt, I'm probably digging where there's nothing to be found. I'd have to look at a few examples of video to convince myself they're synced better with just SCHD data vs with MXm, but it looks like, maybe. Good point on the GPS rate for the data part. Bottom line, there are bigger fish to find in my driving mistakes.

 

You're not alone in digging into the little things and missing what is most important. While it's easy to start seeing the differences in the synch and how the video looks different, has different rates, etc., we are missing the real cause of the whole thing - early throttle pickup. It's important not to let the tech drive our decision instead of just being a tool to improve.

Nice job digging in and seeing what caused the difference. I like finding it in the data and then being more aware as I drive. With the predictive on the dash, I can then know what events cause the increased time, feel it as it happens, and see it on the predictive. It really helps to fine tune your feel in the car.

 

I find side by side video comparison synced with data, especially when done perfectly, to be a great tool. The attitude and yaw of the car throughout the turn in, as well as the lateral placement of the car, can often explain, WHY throttle pickup is early or late.

It's great that this additional data is now accessible in AiM, for sure.