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Re: [Linphone-users] Re: [Linphone-developers] Linphone on BlackBerry an

From: jehan monnier
Subject: Re: [Linphone-users] Re: [Linphone-developers] Linphone on BlackBerry announce
Date: Wed, 12 Jan 2011 21:08:50 +0100


Agree for G711, but from our tests, it was not possible to get/write  PCM audio in real time from the BB.

2011/1/12 Dragos D <address@hidden>

I think you can encode pcmu in Java in real-time.

On Jan 12, 2011 1:45 PM, "Kristian Kielhofner" <address@hidden> wrote:
> On Wed, Jan 12, 2011 at 12:48 PM, Jehan Monnier
> <address@hidden> wrote:
>> As BB applications are pure java, it is nearly impossible to encode/decode voice at the application level. For audio encoding, we rely on what RIM provides. So far only AMR-NB is available in realtime. Today, we think the best is use  "server based" transcoding. We are thinking about providing a server with transcoding capabilities.
> Ideally you wouldn't want to implement this server as a standalone
> component because the delay and potential issues introduced by another
> device proxying the RTP could have a serious impact on call quality.
> Implementing transcoding to/from AMR on the final host providing the
> service is no different than transcoding ilbc or anything else
> (assuming you're going to G711u/a).
> For the server you may want to look at Sangoma hardware transcoding boards:
> They're supported by Asterisk and FreeSWITCH today (although I'm not
> sure AMR-NB is available from the codec API). I've found that
> licensing and indemnifying patented codecs such as G729 and AMR isn't
> really worth it in many cases. If you were to research licensing for
> a software implementation you'd find it's quite the hassle.
> These boards are often cheaper than their software counterparts
> (depending on volume) and offload the transcoding from the host CPU
> which is a significant advantage if you intend on large call volume.
> --
> Kristian Kielhofner
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> Linphone-users mailing list
> address@hidden

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