H.263 compresses video over IP

Whether it's the convenience of holding face-to-face meetings globally or the value of watching remote assets from a central office locally, the potential of video over IP is growing. Physical security and public safety organizations are driving the demand to implement enhanced digital video tools, and technology now allows for migrating those tools onto a communications network.

You don't need to upgrade your network to Gigabit Ethernet to transmit video over IP because video compression, specifically the H.263 standard, provides a cost-effective alternative to increased bandwidth.

In the world of video compression there are two types of choices: proprietary compression algorithms created by several manufacturers, and standards-based technologies such as H.263 and the Moving Pictures Experts Group (MPEG) family, including Motion JPEGs.

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There are options in each category, although the actual application - be it security, e-learning or videoconferencing - will drive the decision. The two most popular standards-based technologies are Motion JPEG and H.263.

Motion JPEG

Commonly known as MJPEG, this compression algorithm is a distant cousin of the MPEG and is commonly seen in digital video recorders. Typically, MJPEG is used in the physical security environment to translate analog video from closed circuit television cameras into a digital stream to be stored onto a hard drive.

MJPEG has the capability to send very high-quality pictures, but it requires an enormous amount of bandwidth - as much as a T-1 circuit - to produce full-motion video. MJPEG does not use interframe coding, unlike MPEG, and is easier to edit with a nonlinear editor.

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However, MJPEG images are among the largest to store on a digital medium and require large amounts of disk space to meet the needs of most businesses today. It is perhaps the most inefficient coder/ decoder (codec) to use in an application such as physical security where the camera needs to be on for extended periods of time. This technology is better for applications when a "snapshot" photo is the desired outcome.

H.263

H.263 lets users scale bandwidth usage and can achieve full-motion video (30 frames per second) at speeds as low as 128K bit/sec. With its flexibility and bandwidth and storage savings, H.263 has a low total cost of ownership and provides a quick return on investment.

H.263 was developed to stream video at bandwidths as low as 20K to 24K bit/sec and was based on the H.261 codec, but as a general rule, it requires half the bandwidth to achieve the same video quality.

Originally designed as the standard for videoconferencing over ISDN, H.261 introduced features such as motion prediction and block transformation. This allowed for a smoother picture with good quality, but was limited in the amount of motion it could handle. Also, H.261 used a large amount of bandwidth (64K to 2M bytes) and was targeted primarily at circuit-switched networks.

H.263 has largely replaced H.261. As H.263 became popular because of its high-quality video at low bandwidths, the standard was annexed and updated nine times. IT managers can feel comfortable placing it on their data networks, without increasing bandwidth and storage costs, or interrupting other critical voice and data applications already running on the network.

The H.263 algorithm also can be modified by today's more savvy developers to produce better results and better compression schemes, which in turn gives end users more choices in selecting the implementation that best fits their business applications.

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