Ron, thanks for your interest. The card was formatted. I was actually flying.
Here is the strange thing. I have video files as well as name matching telemetry files, but some of the files contain data while others do not. Those that do are anywhere from 70k to 500k in size, while those that don't are 1k each. The ones that don't contain data do have the column headers, but nothing more. Could the ones that do contain data be referencing more than one video?
This sounds like the ST10 firmware is not the latest.
V1.07 does not record the small header only files. The previous firmware did.
Are you using the latest firmware in the Q and the ST10?
Video files are not linked directly to telemetry. They are recorded every time you select video recording on the ST10. The file name is the date and time (remember to set your date and time correctly in the ST10). If you start and stop recording twice during one flight you will get two video files but only one telemetry file for that flight (1.07 firmware).
The telemetry files are linked together. You will find three files, two for the TX and one for the Q. They record at the same time and have the same number in the file names.
If you leave the TX switched on whilst you change the Q's battery for a second flight you will only get one larger telemetry file. I suggest you power off the TX when changing batteries.
Also if you fly out of radio range the ST10 will start another telemetry file when you are back in range.
Telemetry is sent back on the 2.4GHz control link so even if you loose video the telemetry will carry on recording unless you go out of control range.
If you have the camera set to record video and you go out of video range the camera will record one continious file but the ST10 will have two video files for that flight.
If you happen to be recording video and have a crash and the camera disconnects, the files in the camera may loose the last few seconds of the crash, even if you do the normal trick of plugging it back in and either taking a still or short video (this sometimes fixes a corrupt file in the camera).
The file recorded on the ST10 will be up to the moment that the camera looses power and may just give you more information for your "air crash investigation".
The telemetry is also really great for trying to detimine what happened! Values are recorded up to several times per second, possibly more data than a black box on a commercial plane!
Note that if you do a firmware update you need to clear the old telemetry files off the card or new ones will not be written. There is a slight file naming difference between the old and new in that the numeric part of the file name has one more character.
The format of the telemetry files has also changed very slightly but they still work in GPSvisualiser etc.
For those that don't have a memory card in your TX I strongly suggest you should pop one in as soon as possible. It dosn't need to be a big card - an 8Gb will record files for a long time.
The data on the card can really help you (and Yuneec) if you have a prang or worse.