A video stream can contain between 24 to 30 frames per second. A TV quality frame (640 x 480 x 24bits/pixel) consumes around 921,000 bytes. This equates to 27MB per second of just video data alone. The compression ratio of lossless methods (e.g., Huffman, Arithmetic, LZW) is not high enough to distribute video over a network like the Internet. Therefore a better means of compression for video and audio files is necessary.
Video compression algorithms were created to enable video to be saved on a computer. A compressor algorithm takes an original uncompressed image or video and reduces its size. Because of the smaller size, the speed requirements for the storage devices are greatly reduced. To play back the compressed data, a decompression algorithm is used to decode the data so it can be displayed on the screen.
MJPEG is a standard, single-frame compression algorithm. Each frame is compressed using JPEG compression. Being a standard type of encoding, MJPEG files created on a computer with a software codec or hardware capture board can be played on another computer using another MJPEG codec or another hardware capture board. CLICK HERE TO DOWNLOAD AN EXCELLENT VIDEO CODEC.
Here's one example of when to use video compression:
You are capturing video but the capture program is dropping too many frames. If you are capturing uncompressed video, then your hardware storage device (i.e. hard drive) may not be able to keep up with the amount of data that is being captured. You will improve the frame rate using a video compression codec.
If you're interested in Audio Compression Codecs click on one of these links: