Today I got my camera board and started testing immediately.
My intention is to use it as a dashcam in my car. The plan is rather simple. On starting the car, the raspberry powers up and starts recording. Turning the car off will immediately shut down the raspberry.
And here's the problem.
I noticed, that when it is recording, and power is shut down, the actual saved data seems to be quantised in length.
If I record for less then 35 seconds, the resulting file is empty. Everything between 35 seconds and about 1:20 minute, will be 35 seconds long, disregarding everything after that mark. After that the limit seems to be at 1:20 min. So, worst case is I loose maybe half a minute of recording when I simply power off. I also tried it with -g 10, but it had no effect.
Can this be controlled? Or does it rather have to do with the way data is stored on the sd card? Could this be helped if it would save on usb rather than SD? It would be great if a power loss would not lose much data, or none at all.