CUVID on GeForce GT 730 and GeForce GTX 1060 does not report any error when
decoding 8K h264 packets. However, it does return an error during
cuvidCreateDecoder call if the indicated video resolution is not
supported.

Given that stream resolution is typically known as a result of probing
it is better to use this information during avcodec_open2 call to fail
immediately, rather than proceeding to decode and never receiving any
frames from the decoder nor receiving any indication of decode failure.
Signed-off-by: Timo Rothenpieler <timo@rothenpieler.org>