Video CODECs - the Fundamental of Digital Video Recording

Video CODECs are compression / decompression means or choices we used to modify the video that is being digitized. In general, CODECs reduce the amount of bandwidth and storage needed at the expense of using more CPU cycles (which are getting cheaper with the development of technology).

Operationally, a video is made up of a stream of images. When we use a CODEC, we can compress the video in two fundamental ways:

- Compress the individual image by itself (intraframe compression), which is the way MJPEG does.
- Compress a series of images together (interframe compression), which is the way MPEG-4 & H.264 do.

For MJPEG, if we are streaming video at multiple frames per second, we are sending basically the same image over and over again. For MPEG-4 and H.264, often a whole image is sent first, the rest of the times they only send updates describing what parts of the image have changed. The result is a significant reduction in storage and bandwidth but it takes more CPU cycles to examine groups of images and make complex calculations. H.264 uses much more complex and sophisticated rules than MPEG-4 to do the compression and hence consumes even more CPU cycles.

Historically, products move from MJPEG to MPEG-4 to H.264. However, with the rise of megapixel cameras, the huge increase in resolution demands more CPU cycles to be allocated. As such, most commercial megapixel cameras use MJPEG, especially if they are multi-megapixel (more than 1.3 MP). New approaches are being sought to reduce the use of CPU cycles in compressing megapixel camera feeds.

To look for the most updated Digital Video Recorders, please visit http://www.jupisys.com/product.html.