Managing Video Compression Formats for Optimal Network Load
The last point to discuss about bandwidth management is the ability for a video management system to support multiple compression formats that are available from the IP video sources. The most common video compression formats in IP video surveillance are: H.264, MPEG-4, MJPEG, MPEG-2, Wavelet and JPEG2000, and each of these compression formats have their own pros and cons. The decision of selecting one compression format over another is based on multiple factors such as:
- Image quality
- Storage requirement
- Number of cameras
- Bandwidth consumption
MPEG-4 and its successor, H.264, are the most efficient compression formats available today in terms of bandwidth utilization. These compression formats are usually the best choice when it comes to bandwidth and storage savings without compromising video quality, as opposed to MJPEG which can offer a great picture quality but has a big impact on the bandwidth. MJPEG can still be a good compression format especially when it is used at a low bitrate on slow links because each frame is independent. So, unlike H.264 and MPEG-4, if one frame is lost in MJPEG, it is not a whole sequence of frames that will be lost, but really only a single frame.
On the other hand, if we look at figure 8, with the same level of video quality, we can clearly see the variation between different compression formats (H.264, MPEG-4 and MJPEG). With approximately one-sixth of the bandwidth utilization used by H.264 over MJPEG, H.264 is clearly the best choice when it comes to bandwidth and storage optimization.
Now, since IP video surveillance is living the same evolution as TV broadcasting is with HDTV, IP video sources also offer higher resolutions with network throughput-intensive megapixel cameras, and thus H.264 will most probably become the standard compression format in the industry due to its low bandwidth utilization. This is why is it important to look for a somewhat future-proofed VMS that supports the advanced technologies of today and tomorrow.
Making It All Come Together: The Video Management Software
Multicasting, multistreaming and video compression are three of many ways to optimize bandwidth utilization in IP video surveillance applications. The edge devices or IP video sources are becoming more and more intelligent, providing some of the functionalities that were initially only provided at the head-end level by the video surveillance platform. For example, some IP video sources are able to perform video analysis directly at the edge and only stream the video upon alarms. Even better, some IP video sources can store the video directly at the edge and act as mini-recording units.
Nevertheless, all of these intelligent functionalities absolutely need to be brought forth by the video surveillance platform for users to truly take advantage of all their related benefits. With a strong and innovative VMS, users will be able to fully leverage the latest advancements in technology, directly contributing to a reduction in bandwidth requirements, an optimization of network resources, and a decrease of storage needs. Ultimately, an advanced VMS will help users to effectively cut back significant costs and help to keep their investments future-proof as newer technologies emerge.
Francis Lachance is Product Manager at Genetec for Omnicast IP Video Surveillance.
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