Saturday, February 18, 2017

Syncing video with altimeter data...

If you spend some time watching rocket vids on YouTube and other places you are bound to run across a few with the altitude, speed, and other data merged in with the flight video, often in a very stylish and colorful fashion. I always wondered how they did that, so last night I did a bit of googling to figure out what software was available. The search quickly pointed me to DashWare - a free product bought out by Go Pro a couple of years back. It had fabulous reviews, and seemed like a good thing to try, except for a couple of things - 1) It's a Windows only program, and 2) is no longer actively supported. Fortunately, I have a Windows 10 laptop (don't tell my macs!), which was quickly used to download the software; you can't beat free. I installed DashWare, placed a flight vid and the altimeter data associated with that flight in my Dropbox so I could access it from the PC, and ran the program.

Right into a brick wall...

DashWare would not load my movie, even though it was one of the supported file types (Quicktime MOV) - the preview pane showed nothing but gray. I spent about an hour checking codecs, running Windows 10 video diagnostics, and cursing the Microsoft empire, but nothing helped. I then did what I should have done in the first place - googled the problem. It turns out that DashWare does not support Windows 10, but there is a fix - you have to delete a DLL in the DashWare application directory and run the program from there; if you try running it from the desktop icon (which I deleted), it will "fix" the fix. Once this was done, the video loaded with nary a problem.

The DashWare main screen - Did I mention that it can add a title and end credits too? Click to enlarge.
DashWare makes superimposing data on the video pretty simple, the first step involving importing the video and data files. The software supports numerous data file formats, but the most important from an altimeter perspective is the ability to import CSV (comma separated values) files, which can be created from all altimeter software packages. Once the CSV file is imported, one applies a "data profile", which matches the columns up to variables understood by DashWare. Obviously, the most important of these is time, which is a required column - without it, you can't sync to the video. Creating data profiles is fairly easy, and I made and saved two - one for my Altus Metrum Micropeak and the other for the Jolly Logic Altimeter 3. You can also create computed columns in the data profile, like one that calculates G's from acceleration in feet per second squared.

After you have the video and data imported, you next need to create or select a gauge that will display the data on the video. There are a fair number included with the software, and, given that this was my first time using the package, I chose one of those. After you create or pick your gauge, you drag it to the desired location on the video preview and link the gauge inputs to the appropriate column variables in the data file. Very easy peasy, except that you need to remember to use one of the small gauges for standard resolution vids from keychain cameras and the like - DashWare is focused on HD (not surprising given the Go Pro connection) and so the larger gauges will cover a lot of the screen real estate in a SD movie.

The last step is to synchronize the video with the data, which is done by advancing the video to the frame which corresponds to the start of the altimeter data (first motion on the pad in the two flights I worked with) and check the sync with video box. DashWare will then do all the stuff needed to merge the two, and it is pretty neat to watch the gauges update in real time. I was amazed at how well it works - the altitudes - as judged from rocket turnover near apogee and landing - appeared to be pretty much spot on throughout the flight. Once this is done, you can export the project video to a stand alone file, which can be played, uploaded to YouTube, or whatever.

Standard definition keychain camera flight video with Jolly Logic Altimeter 3 data superimposed in lower left corner.

HD flight video with speed and altitude information from Micropeak altimeter displayed in lower right corner.

It's a shame that DashWare is no longer supported, as it is a very nice package. The searching turned up similar products, but none appears to be as easy to use. If you have a Windows box, or a computer with a Windows VM, you might want to use it to dress up those flight videos. After all, data displays make everything look cooler.

1 comment:

  1. Thanks for the quick tutorial, Bill! I will use this in the upcoming flying season, 2017.