At the time of writing this post, my experiences are as follows:
- FLV – iOS good, Android good
- F4V – iOS bad (‘Unsupported Content’), Android good
- MP4 – iOS bad (‘Unsupported Content’), Android good
There may be nuances in the F4V encoding that solve the iOS issues, but the simple answer is that if you want the most bang for your buck then in my experience, plain old FLV is the best format across all devices right now