add openh264 support #2206

Job	Run time
code formatting check	26s
cppcheck	4m 21s
min features with gcc	2m 48s
min features with g++	1m 57s
min features with clang	2m 59s
max features with gcc	4m 7s
max features with g++	3m 37s
max features with clang	4m 52s
max features with clang and AddressSanitized	9m 11s
max features with gcc and DEBUG	3m 10s
max features with gcc for 32-bit arch (legacy OS)	2m 26s
max features with g++ for 32-bit arch (legacy OS)	1m 33s
max features with clang for 32-bit arch (legacy OS)	2m 45s
	44m 12s

Provide feedback