[Freeswitch-users] mod_rtmp audio codecs issues for speech recognition?

[x.liu]

Hi Peter,

Many thanks for your response and suggestion!

I will report it to Jira and report back here when it is resolved.

Thanks again,

Xing


On 08/15/2012 12:58 PM, Peter Olsson wrote:
> I noticed this as well when I was playing around with UniMRCP and Nuance some time ago. mod_unimrcp  seems to be missing some code to resample the audio frames to the bitrate used by the nuance connection. If I remember correctly it was ok to use (for instance) PCMA on the call leg and PCMU on the nuance leg (they both use 8khz), but as soon as I tried to use a codec with another rate things seemed to stop working.
>
> I never had the time to chase this down any further, and I was only trying it for an internal test case, so it wasn't so important for me.
>
> I believe the best thing you can do is to report this to Jira, and hopefully someone will be able to look into this.
>
> /Peter
>
> -----Ursprungligt meddelande-----
> Från: freeswitch-users-bounces at lists.freeswitch.org [mailto:freeswitch-users-bounces at lists.freeswitch.org] För x.liu
> Skickat: den 15 augusti 2012 13:35
> Till: freeswitch-users at lists.freeswitch.org
> Ämne: [Freeswitch-users] mod_rtmp audio codecs issues for speech recognition?
>
> Hello,
>
> I am trying the FS sample Flex client for TTS and speech recognition.
> The TTS sounds OK. I use Nuance MRCP v1 server with Nuance recognizer 9.
>
> The problem is that I hardly get the recognition result,only occasionally I got some simple words output like "repeat", "ok" which were not I said.
> The whole recognition setup works well when I use a telephone line but basically not work by using the flex client from a web broswer.
> The recorded voices in FS which were sent from the web browser via the flash rtmp sound fine.
>
> I guess it may be the audio codec issues. The flash rtmp uses Speex. My mrcp profile specifies the codecs as "PCMU PCMA L16/96/8000"
>
> Is there a way to automatically convert the Speex audio to the mrcp required formats during calling the system?
> Or what should I look at to get the proper speech recognition via the flash rtmp?
>
> Many thanks!
>
> Xing
>
>
>
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-- 
Heriot-Watt University is the Sunday Times
Scottish University of the Year 2011-2012

We invite research leaders and ambitious early career researchers to 
join us in leading and driving research in key inter-disciplinary themes. 
Please see www.hw.ac.uk/researchleaders for further information and how
to apply.

Heriot-Watt University is a Scottish charity
registered under charity number SC000278.