H.261 vs H.263

[daniel.asplund]

Which protocol do you recommend to use?

H.263 is specified to work on low bandwidths but which protocol is to prefer on high bandwidths, +384Kbps?

[sachon]

The original intent of H.263 was to work as a codec for H.324 - video over POTS. Most H.323 and H.320 vendors have adopted H.263 for business quality VC (i.e., 384k+) as well as they have found performance benefits at even these levels. H.263 (and its various annexes) are the preferred methods of encoding in the latest systems at nearly all supported speeds (129k - 2Mbps). H.261 would only be used as a "least common denominator" when new codecs communicate with older codecs that may not support H.263.

[mero]

H.263 compression differs from H.261 in one way only: It makes the assumption, that consecutive image frames consist of a non-moving background with an egg-shaped moving foreground. It provides a significant better ratio of compressionen vs quality only if this assumption is almost true.

Therefore it often will be suggested for low-bandwidth desktop endpoints, where one person is sitting in front of a non-moving cam. However, this advantage of H.263 is present at higher bandwidths and group systems too, if you carefully focus on single speakers.

H.261 makes no assumptions on the image content and works as good as H.263, if VCRs, computer live streams, changing backgrounds or groups of people are presented.

HopeThatHelps

Mero

[zabriskis]

H.261 was a better protocol when H.263 was first introduced for higher bandwidths. BUT with H.263+ the annexs provide for features that are not available in H.261, so if the terminals are using some of the advanced features of the H.263+ it is better. If the terminal does not use the H.263+ annexs H.261 is better.