h264parse: Add a method to blindly timestamp based on framerate
Submitted by Robert Swain
Sometimes one may encounter a raw h.264 file that doesn't have any timestamp information. It may be useful, at least for testing purposes, to be able to apply timestamps to the frames using h264parse.
The idea is that if the sink pad caps state the stream-format=byte-stream and contain a framerate, this is can be used to override the buffer timestamps by starting from zero and adding the frame duration for each frame.