Compression

Compression techniques are used in Digital CCTV to reduce the file sizes of recorded video images. Typical compression formats used for video are: MJPEG, MPEG4 & H.264.

There is not a significant storage or bandwidth savings in comparing MPEG4 part 2 and MPEG4 part 10 (H.264). The significance is seen when comparing to MJPEG for higher resolution models in the Megapixel range. However, none of the H.264 Megapixel security cameras in the market today use the same H.264 compression. H.264 was just standardized at the end of May. Some companies have lines utilizing H.264 are proprietary variations of the compression.

Depending on the NVR software you are using in unison, H.264 can be troublesome on your hardware. If the software does a small recompression of IP video when it receives it, you will need a lot of horsepower to use a lot of H.264 streams in comparison to MPEG4 and MJPEG. That is the trade off for the smaller file sizes and bandwidth. Takes more processing power.

H.264 should increase CPU utilization over MPEG4, not MJPEG. I am not surprised that MJPEG decoding is using more CPU than H.264, given the much higher bitrates and the fact that every frame of MJPEG must be decoded (including redundant information).

Using H.264 for standard definiton security cameras is not as urgent to switch at then it is for megapixel. By contrast, with megapixel, moving from MJPEG to H.264, the dollar savings in storage are very significant.

MPEG2 - Older standard, not bad but not great.
MPEG4 - Good standard still used in many analog DVRs and some standard definiton IP Cameras.
MJPEG - Used in many Megapixel cameras. Not a very good compression but provides quality images.
H.264 Very good compression that now with industry standards in place will likely become the standard of choice in most applications.

It is important to note as well that some PC DVR manufacturers have developed their own compression algorithims that work just as well or better than H.264. One example is 3xLogic and their line of PC based DVRs that use Aztech compression.

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