[Vorbis] patent issues with Vorbis

[KumarBraj Bhushan]

Hi,

We are in the business of developing/productizing Multimedia codecs for embedded systems. Recently, Vorbis has gained good popularity. We are also developing it. 

But we face few problems related to patents. Vorbis claims to be patent free. Is there any particular search made for possible patent infringements and corresponding report published? We need to convince our customers sometime about this issue. 

I have started with patents listed on the website of "www.mp3licensing.com". Some of them are very generic and it appears as if Vorbis code might be infringing upon few of them. They are (with their patent numbers and titles) :

5,384,811: Method for transmitting a TDAC coded audio signal
5,321,729: Method for transmitting a signal using adaptive window functions
5,214,742: Method for transmitting an audio signal using adaptive window functions
5,742,735: Digital adaptive transformation coding method

They are many other patents for stereo processing, which are not of much that concern as the one sited above. Does anyone know about more such patents?

I see some discussion done on the patent issues in this mailing list. Did it stop there only? http://lists.xiph.org/pipermail/vorbis/2003-December/024618.html
In Hydrogenaudio forum also some discussion happened. http://www.hydrogenaudio.org/forums/lofiversion/index.php/t13686.html
What is the current stand of the people/developers associated with Vorbis about the patent issues?


Cheers,
-Kumar.