I recently started recording my FPV flights and to help me tune my PIDs, I thought I would try overlaying BlackBox data on the video. The flight controller I am using – the XRacer F303 V2 has 16MB (Megabytes, not Megabits) of dataflash, allowing me to log almost one entire flight, even at 1/1 logging at 4 kHz. The method I originally attempted was the one described in Oscar Liang’s blog post. After waiting a LONG time to render the frames, I ended up with over 13000 pictures that would need to be stitched together. I did not want to spend money on Quicktime Pro to do this and the free tool I was using – Sequimago; wasn’t able to handle so many pictures at once. I managed to stitch together 20 seconds of video, then I had even more trouble trying to overlay it on the flight video.
While going over the log again, I suddenly realised that Blackbox Explorer extension for Google Chrome had an “import video” option. This was far easier to use than the procedure I was trying earlier. Here are the steps you need to follow to overlay Backbox data on your flight videos:
- If you don’t have it already, download and install Blackbox Explorer
- Click “Open log file/video”, browse and open either your log or your video (the order doesn’t matter).
- Once the log/ video opens, click “Open log file/video” again and now open the video if you already opened the log and vice-versa.
- Now you need to synchronise the blackbox data with the flight video. The best way to do this is to identify where the arming beep sounds in your video and synchronise the “Arming beep begins” bar in the log to that. Note that part 5/5 of the log file corresponded to the first part of the video for me so do not assume that 1/x will be the first part of the log. Now is the time to select what parameters you wish to plot as well. In my case, they were RCCommand, Gyro, and the PIDs for the roll axis as this the axis I was tuning.
- Play the video to ensure that is synced. Once you are sure it is synced than simply select “Export video…” choose whatever settings you want and wait for it to render (this takes several minutes).
That’s it! I hope this post was helpful 🙂