DVR Compression - The Online Security Specialist
There are several different types of compression formats, and its not easy for anyone, including installers, to decide which one is more suitable for there requirements. So for now we will try to educate you on what compression actually is, and then let you know a little about the different types of compressions used by the manufacturers of the Digital Video Recorders we offer.
So what is compression?
If you consider a digital camera with a Gigabyte of storage capacity can only hold a few hundred images (photos), CCTV systems may need to store up to 25 images every second for every camera. Unless we decrease the size of these image files the amount of storage capacity required for CCTV systems would be huge, and unpractical.
Compression is basically the process of reducing the file size of images to reduce storage space required
Compression Concepts
Concept Name |
Figure |
Description |
|---|---|---|
| Spatial Compresion | Figure 1. Spatial Compression |
Used on a single image as a completely independent entity with no relation to other frames, and removes data not useful for describing the image. |
| Temporal Compression | Figure 2. Temporal Compression |
Focuses on storing the changes between subsequent images (frames) rather than the entire frame in isolation. If very little changes between subsequent frames then very little storage space is consumed. |
Compression Formats
Compression |
Information |
Conclusion |
|---|---|---|
H.264 |
Relatively new compression within the security industry but is becoming very 'fashionable'. Compresses the files more than any format, allowing for large amounts of storage proportionally to other compressions, also due to file size less bandwidth is used for remote viewing. | Great compression where large recording times are one of the most important factors of choosing your Digital Video Recorder. |
JPEG2000 |
Largest file size of all compressions, so uses more storage space than all others. But it is this large file size that allows it to produce the best quality images. | Best compression when image quality is the most important factor for choosing your Digital Video Recorder. |
MPEG-4 |
This compression is an 'all rounder'. Although it doesn't have the image quality of the JPEG2000 or the decreased file size of H.264 it produces good quality images at a more than acceptable file size. Explaining why it has been in the market for so long and is still a popular choice amongst manufacturers. | Good all rounder. |
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