Re: [codec] draft test and processing plan for the IETF Codec

Dear Koen,

Several organizations do define a send and receive frequency masks for terminals, these are requirements that have to be fulfilled by terminal manufacturers. Given these masks, one can only assume that the audio signal will be picked-up and reproduced within these defined ranges. 

I agree that outside what is defined and required by certain organizations, it is  pretty much a wild jungle.

Kind regards,
/Anisse 

> -----Original Message-----
> From: Koen Vos [mailto:koen.vos@skype.net]
> Sent: Tuesday, April 19, 2011 11:31 PM
> To: Anisse Taleb
> Cc: codec@ietf.org
> Subject: Re: [codec] draft test and processing plan for the IETF Codec
> 
> Hi Anisse,
> 
> > Besides the DAC and AA filters, you cannot expect that every loudspeaker,
> > headset, earplug, microphone out there to have a flat frequency response
> > regardless of if it is a VoIP application or something else. Specifying a
> > frequency mask helps in reducing some of the variability and uncertainty
> > due to these and other external factors.
> 
> Most of your external factors depend on the listening setup, but are
> otherwise
> constant over all tests.  So how can you possibly mitigate the "variability
> and uncertainty" with frequency masks that are _constant_ over all setups,
> and
> which -for unclear reasons- depend on the (bandwidth of the) listening
> test?
> 
> best,
> koen.
> 
> 
> ----- Original Message -----
> From: "Anisse Taleb" <anisse.taleb@huawei.com>
> To: "Koen Vos" <koen.vos@skype.net>
> Cc: codec@ietf.org
> Sent: Tuesday, April 19, 2011 2:16:49 AM
> Subject: RE: [codec] draft test and processing plan for the IETF Codec
> 
> Dear Koen,
> 
> Let's mimic the real world as closely as possible :-).
> 
> Besides the DAC and AA filters, you cannot expect that every loudspeaker,
> headset, earplug, microphone out there to have a flat frequency response
> regardless of if it is a VoIP application or something else. Specifying a
> frequency mask helps in reducing some of the variability and uncertainty
> due to these and other external factors.
> 
> That aside, I am not against revisiting these in getting something that all
> agree on.
> 
> Kind regards,
> /Anisse
> > -----Original Message-----
> > From: Koen Vos [mailto:koen.vos@skype.net]
> > Sent: Saturday, April 16, 2011 7:04 AM
> > To: Anisse Taleb
> > Cc: codec@ietf.org
> > Subject: Re: [codec] draft test and processing plan for the IETF Codec
> >
> > Hi Anisse,
> >
> > I noticed your plan tests with band-limited signals: Narrowband signals
> are
> > filtered from 300-4000 Hz, Wideband from 50-7000 Hz, Superwideband from
> > 50-14000 Hz.
> >
> > However, VoIP applications have no such band-pass filters (which degrade
> > quality and add complexity).  So results will be more informative to the
> WG
> > and potential adopters of the codec if the testing avoids band-pass
> > filtering as well.  We want test conditions to mimic the real world as
> > closely as possible.
> >
> > Instead of band-pass filtering, tests on speech could use a simple high-
> > pass
> > filter with a cutoff around 50 Hz, as many VoIP applications do indeed
> have
> > such a filter.
> >
> > best,
> > koen.
> >
> >
> > ----- Original Message -----
> > From: "Anisse Taleb" <anisse.taleb@huawei.com>
> > To: codec@ietf.org
> > Sent: Wednesday, April 13, 2011 12:32:00 AM
> > Subject: [codec] draft test and processing plan for the IETF Codec
> >
> > Hi,
> > Please find attached a first draft of a test plan of the IETF codec
> (Opus).
> > The proposal does not claim to be complete, there are still many missing
> > things, e.g. tandeming cases, tests with delay jitter, dtx etc. Consider
> it
> > as a starting point for discussion where everyone is welcome to
> contribute
> > in a constructive manner. Further updates are planned, but let's see
> first
> > some initial comments.
> >
> > The attachment is a pdf version, please let me know if you would like to
> > see another format and I would be glad to oblige.
> >
> > Comments and additions are welcome!
> >
> > Kind regards,
> > /Anisse
> > (From La Jolla - San Diego).
> >
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