One that I know of is User Agent detection to find out the device. It look like user agent could be change by the service providers for some reason. Are there any other robust methods of device detection or the mobile technology is yet to evolve?
Note: The detection is not restricted to any particular technology. Primarily looking for video compatibility across devices. I have tried to implement solutions available in market, but they have some limitation or other and does not allow full customization required. So I'm looking to develop one.
It depends what you need, but I usually use this one: http://51degrees.mobi/
If you don't need very detailed info you can use free service, but for example, if you need mobile/tablet division you would have to pay for their service.