[Blink] New Blink Qt release 0.4.0 for Windows

[mgraves at mstvp.com]

Hi All,

I have been experimenting with a couple of recent Opus implementations
in soft phones. Some allow more end-user adjustment of things than
others. Some allow you to set the sample rate independent of the bit
rate. 

Opus supports a maximum sample rate of 48 KHz, which by the way is the
standard used by the broadcast and pro-audio industries for hardware
design. 

I'm told that Opus always reports it's sample rate as 48 KHz in SDP, as
that's what it might do given the network capacity.

Of course, there's more to call quality than just sample rate. However,
some rudimentary testing with basic tones reveals that Opus at 48 KHz
and around 50 kbps sounds quite clean.

http://www.mgraves.org/2013/05/experimenting-with-opus-i-phonerlite/

Michael Graves
mgraves  mstvp.com
o(713) 861-4005
c(713) 201-1262
sip:mgraves at mjg.onsip.com
skype mjgraves

> -------- Original Message --------
> Subject: Re: [Blink] New Blink Qt release 0.4.0 for Windows
> From: Adrian Georgescu <ag at ag-projects.com>
> Date: Fri, June 28, 2013 2:45 pm
> To: Blink Support Forum <blink at lists.ag-projects.com>
> 
> 
> On Jun 28, 2013, at 9:17 PM, Mediacast Guy <mediacastguy at gmail.com> wrote:
> 
> > I'll confess that I'm not a codec expert but I'm referring to bitrate. A sample rate of 48kHz is more than adequate, but a low bitrate makes a high sample rate meaningless. CDs have a sample rate of 44.1 kHz with a bit dept of 16 bits and a bitrate of 1.35Mbit/sec. Most video streams have a sample rate of 48 kHz. 
> > 
> > In MP3 (compressed audio) parlance, you can compress from 8 kb/sec to 320 kb/sec bitrate while the sampling rate can be from 8 kHz to 48 kHz. Obviously, 128K bitrate MP3 audio sampled at 48 kHz sounds much better than 32K bitrate MP3 audio sampled at 48 kHz. The ultra-wideband audio deteriorates from low bitrate, not low sample rate.
> > 
> > I have done testing with the Opus codec at 48 kHz sampling rate with another SIP client,
> 
> That is because even if OPUS codec can use internally 48KHz sample rate that covers most human audible spectrum, the softphone you have used employs a smaller sampling rate like 8 or 16kHz, which renders the OPUS codec advantages useless, so you cannot hear any difference compared with let's say G722. Unless the whole audio processing chain works at the codec speed speed, the codec performance will not be visible.
> 
> > and the audio does not compare favorably with Skype's SILK Version 3 codec.
> 
> For the reasons explained above..
> 
> > TeamSpeak is close with its server that doesn't cap bitrate, but it's still not as good as Skype.
> 
> Current Blink build I am using sounds better than Skype so you will not be disappointed.
> 
> Adrian
> 
> > 
> > MCG
> > 
> > On 6/28/2013 8:07 AM, Adrian Georgescu wrote:
> >> Do you mean sampling rate?
> >> 
> >> Adrian
> >> 
> >> On Jun 28, 2013, at 2:05 PM, Mediacast Guy <mediacastguy at gmail.com> wrote:
> >> 
> >>> Awesome. Hopefully you will include Opus without including a bandwidth limit. Let the limit be the codec's limit.
> >>> 
> >>> MCG
> >>> 
> >>> On 6/27/2013 2:30 AM, Adrian Georgescu wrote:
> >>>> Not in this release but should be in the next one.
> >>>> 
> >>>> Adrian
> >>>>  
> >>>> On Jun 27, 2013, at 12:03 AM, Mediacast Guy wrote:
> >>>> 
> >>>>> No new codecs, like Opus?
> >>>>> 
> >>>>> MCG
> >>>>> 
> >>>>> On 6/26/2013 12:12 PM, Adrian Georgescu wrote:
> >>>>>> Version 0.4.0
> >>>>>> 
> >>>>>> June 26th, 2013
> >>>>>> 
> >>>>>> Added support for multiple URIs per contact
> >>>>>> Added support for Bonjour presence
> >>>>>> Added minimize to system tray
> >>>>>> Added text eliding using fading colors for labels with long texts
> >>>>>> Adjusted selected group background colors for better visibility
> >>>>>> Save and restore main window geometry across restarts
> >>>>>> Move contact when its name changes to keep contacts sorted
> >>>>>> Updated test contact icon files
> >>>>>> Strip URI domain in history if URI looks like a phone number
> >>>>>> Fixed creating offset-naive datetime for epoch
> >>>>>> Fixed processing when initial winfo document is not full
> >>>>>> Fixed publishing internal presence states
> >>>>>> Fixed losing presence state when contact is modified
> >>>>>> Auto-upgrade will fetch this new version automatically, if disabled go to:
> >>>>>> 
> >>>>>> http://icanblink.com/download.phtml
> >>>>>> 
> >>>>>> Regards,
> >>>>>> Adrian
> >>>>>> 
> >>>>>> 
> >>>>>> 
> >>>>>> _______________________________________________
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> >>>>>> Blink at lists.ag-projects.com
> >>>>>> http://lists.ag-projects.com/mailman/listinfo/blink
> >>>>> 
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> >>>> 
> >>>> 
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> >> 
> >> 
> >> 
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