Reduce mobile data usage

I've used Carv for a week, didn't watch the videos, just recorded all of the runs. I have noticed that whenever examining a specific run, Carv downloads maybe around 10MB of data. This is also done when repeatingly examining the same runs (so it seems no caching is done). Android reports that I've used around 2GB of roaming data on Carv during one week. Besides, this definitely adds to the battery usage, which is already high.

I suggest trimming the information pushed around when viewing results, cache whenever possible, let pre-download all the videos.