the above link says it simple enough, but you have to work it
according to this guy camera send mjpeg, ffmpeg can play mjpeg so avcodec most probably can decode it(untested in hollywood but its the simplest out there)
so you have to work out how each frame (a single jpeg image is the one frame in mjpeg) and construct it.
the guy in this link has reverse enough protocol so it points out where the length of the image begin, so you can calculate
The length of the header is given in the header; there's a 16-bit integer starting at index 30; add 32 to that and you've got the index of the first byte of the JPEG data.
so in general have to decode data$ = REceiveUDPdata(id) , check out the lengh of jpeg image, receive all data frames of iamge
build image (in RAM: for example), and display it