Comments

Chienworks wrote on 12/9/2002, 7:48 PM
I believe that MJPEG is a series of JPEG images for each frame. There is an option for lossless compression in the JPEG spec. So, theoretically, it could be done. The compression ratio would probably be pretty bad though, probably bigger files than DV. Very few still image editors include the lossless JPEG setting because it doesn't compress enough to be worth the effort. I would assume that MJPEG would suffer similar lack of interest.
kkolbo wrote on 12/9/2002, 7:57 PM
The Matrox digisuite uses an almost uncompressed codec. They clain only about .7. It is most likely MJPEG because even without much compression it is considered easier to process than an uncompressed file. Yes the files are huge.

K
riredale wrote on 12/10/2002, 1:44 AM
A lossless compression format (zip, Huffman) can do about a 50% reduction without too much sweat. For natural images, a 5/1 jpeg compression is almost perfect, so I have to wonder why bother with lossless in the first place?
taliesin wrote on 12/10/2002, 3:38 AM
This is true. On lossless MJPEG compression there is no quantization done to the video (which is the lossy part of compression). There is only something similar like zip-packing done.

Marco
GaryAshorn wrote on 12/12/2002, 10:25 AM
I use the old FAST VM/DPR system which is 4:2:2 MJPEG. Compression from near lossless to what ever level I want up 100:1. Quality nice....BIG FILES. MJPEG is great but as said big files and storage. Newer systems use the newer codecs and get good quality with smaller files. My drives are actually controlled by the DPR card and split the frames odd to one drive and even to the other to get the data rate high enough and reassemble back to the system. Old dog by todays standards but the quaility is still there. Read a great article about a year ago about the different digitizing codecs and MJPEG was listed as the method for high quaility if going back to component tape systems for network use but like the new ones for the newer distributions for DVD and other work. Match the needs to the project.