Re: [rtcweb] Video codec selection - way forward

David Singer <singer@apple.com> Wed, 20 November 2013 19:42 UTC

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Subject: Re: [rtcweb] Video codec selection - way forward
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I think we should think hard about H.263 instead of H.261 as the third fallback.  Why?

http://www.itu.int/rec/T-REC-H.263/



H.263 was first published in March 1996, so it's 17 years old.  The restrictions (e.g. on picture size) are no WORSE than H.261.  Yes, more recent amendments deal with this (and a plethora of other issues), so we’d need to settle on which of those are mandatory (the usual profiling discussion).

There are 34 records in the patent database against H.261, mostly from 1989 but one as recent as 2005 (though that is a re-file).  That's 2.2 (reciprocity), as was one other I checked.

Rather surprisingly, there are only 31 against H.263!  The most recent is 2011, and is also option 2.  Most are 1997-2001.


On this quick glance, H.263 appears no worse than H.261. IANAL (as I am sure you have all noticed).


H.263 is much more widely supported and mandated.  It has been mandated in the 3GPP specs for years (for lots of services, including videoconf), and is effectively the fallback codec today in the industry, as I understand.  It was ubiquitous in video telephony for years, and I suspect many of those systems still ship it.

So, would “MUST implement at least two of (H.264, VP8, H.263)” work?

(I am asking the question, not even answering on behalf of my company, yet.  Let’s get the issues on the table.)


David Singer
Multimedia and Software Standards, Apple Inc.