H.263
A video compression specification that 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.
From H.263 compresses video over IP, Network World Tech Update, 09/23/02.
Also see: H.264.
Additional resources
RTP Payload Format for H.263 Video Streams
RFC 2190.
H.263 Video Coding
An older page, but it has some comparative samples of H.263, MPEG and QCIF compression.
Topic: Convergence
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