Use image topic, not stream
Option to specify (or figure out?) the frame rate
Make sure we don't write a video packet first
Handle duplicate headers
Wait for a keyframe!!
Need to flush page for initial identification header packet? And after last header packet?
Handle chaining streams? Need to retroactively set e_o_s on previous video packet.
Check if encoding has changed
Store image encoding in comment
Try not to send headers twice to some listeners
fromImage is deprecated
Optimized gray-scale path, rgb8
fromImage can throw cv::Exception on bayer encoded images
Break this function into pieces
Handle RGB8 or MONO8 efficiently