[h323plus] Silk codec support

Robert Jongbloed robert.jongbloed at bigpond.com
Tue Jan 11 18:26:01 EST 2011

I added SILK to OPAL a couple of months back. Unfortunately it was SIP only
as I did not know what the H.245 encoding is for SILK, if any.

Now that I see there is at least a proposed standard, this should be able to
be finished in a few minutes. It would be really nice if the two systems
could use the same code for this.

Robert Jongbloed
OPAL/OpenH323/PTLib Architect and Co-founder.

> -----Original Message-----
> From: h323plus-bounces at lists.packetizer.com [mailto:h323plus-
> bounces at lists.packetizer.com] On Behalf Of Simon Horne
> Sent: Tuesday, 11 January 2011 9:32 PM
> To: 'Łukasz Czekierda'
> Cc: h323plus at lists.packetizer.com
> Subject: Re: [h323plus] Silk codec support
> Lukasz
> The issue is there is no definition of Silk in H.323
> I wrote a submission to the ITU at the last meeting for inclusion
> http://wftp3.itu.int/av-arch/avc-site/2009-2012/1011_Res/AVD-3994.zip
> The stumbling block is that SILK has defined dynamic payloads for each
> bitrate for interop with Skype.  In H.323 you cannot tell the remote what
> payload to send, the remote will tell you want it will send. This becomes
> issue if you are bridging to skype. There is a work around (submitted by
> Avaya for a different issue but same meeting) to include in the OLCack the
> payload that you expect the remote to send you.
> I have a development H.323 silk plugin (8k and 16k bitrate) and I will
> commit them after the next stable release as it requires audio capability
> merging which needs to be committed. The idea is there is 1 silk
> for the different bitrates (rather than a capability for each bitrate) and
> you negotiate the actual bitrate by merging your local caps with the caps
> the TCS.
> Simon
> -----Original Message-----
> From: h323plus-bounces at lists.packetizer.com
> [mailto:h323plus-bounces at lists.packetizer.com] On Behalf Of Lukasz
> Sent: Tuesday, January 11, 2011 7:42 PM
> To: h323plus at lists.packetizer.com
> Subject: [h323plus] Silk codec support
> Dear H.323Plus team,
> I have a question regarding support for skype's silk codec. Do you plan to
> support it soon? Maybe you have already started development/integration?
> you expect any obstacles?
> Best regards,
> Łukasz Czekierda

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