Subject: [rtcweb] Query Regarding Mandatory audio codecs draft

From: Kiran Kumar Guduru <[email-masked]>
Date: Fri, 25 Apr 2014 10:21:30 +0000 (GMT)

Hi,

I have a query regarding mandatory to implement audio codecs.

In draft-ietf-rtcweb-audio, it has been specified that

"For all cases where the client is able to process audio at a sampling rate higher than 8 kHz, it is RECOMMENDED that Opus be offered before PCMA/PCMU."

Is that means spec is recommending G.711 (PCMA/PCMU) for sampling rate less than or equal to 8 kHz?

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From: Kiran Kumar Guduru <[email-masked]>
Date: Fri, 25 Apr 2014 10:38:23 +0000 (GMT)

Dear Jean-Marc,

Please correct me if my understanding is wrong.

Spec prefers G.711 at 8 kHz sampling rate and RECOMMENDS Opus above 8 kHz sampling rate.

Is my understanding correct?

------- Original Message -------

Sender : Jean-Marc Valin<[email-masked]>

Date : Apr 25, 2014 19:30 (GMT+09:00)

Title : Re: Query Regarding Mandatory audio codecs draft

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> rate less than or equal to 8 kHz?

No. Opus is still a good idea for 8 kHz, but it's not 2119 RECOMMENDED
since there are valid (mostly complexity-related) reasons to use G.711
despite the higher bit-rate.

Jean-Marc
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From: Jean-Marc Valin <[email-masked]>
Date: Fri, 25 Apr 2014 06:46:39 -0400

> Is my understanding correct?

No. The spec does not prefer anything and does not make any
recommendation at 8 kHz. Just like the statement "if it rains, bring
an umbrella" does not say anything about the case where it doesn't rain.

	Jean-Marc