[ubuntu-studio-devel] Qjackctl

Len Ovens len at ovenwerks.net
Sat Feb 27 15:12:35 UTC 2016

On Sat, 27 Feb 2016, Ross Gammon wrote:

> On 02/24/2016 08:52 PM, Len Ovens wrote:
>> The qjackctl that currently ships with 1604 is broken. In fact it can
>> impact other applications including the desktop. Qjackctl is  a large
>> part of our audio workflow and also affects some of our Video
>> applications that rely on jackd for sync purposes. The latest qjackctl
>> builds itself as a qt5 application by default. Ubuntu is set up as a qt5
>> system by default too. However, qjackctl will build just fine as a QT4
>> application and as we already have other QT4 applications all the
>> required Libs are already there. When built as a qt4 application
>> qjackctl seems to work just fine. When looking through the web, it seems
>> qjackctl is not the only application having the same problem with qt5.
>> So the problem is with QT5.
> Have built it successfully with QT4 and as Len says - it seems to work.
> The look it quite different though. I have uploaded it to
> ppa:ubuntustudio-dev/dev-testing if you want to give it a spin.

I will test it from the ppa, though I am quite confident it will work fine 
as I have already tested my own qt4 build.

> I tried to see if there was some other patch we could apply from the QT
> bug tracker or something. But there is so much misinformation about
> different systrays, notification areas, I could not find anything concrete.

That was my findings too.

>> Ga! ubuntu changes the default from debian's 48k to 44.1k, Why not leave
>> it alone? Even intel's internal HDA is designed around 48k. (all analog
>> circuitry makes 48k sound cleaner)
> I can't see any rationale for that 44.1 setting in the changelog, but
> unfortunately, after the Freeze starts we can only really fix bugs.

There is someone in the Ubuntu dev team who has found an audio interface 
that only does 44.1k I think. I have found more devices that only do 
48k... The history is convoluted, but mircosoft/Intel PC hardware has used 
48k as default since AC97 at least. And tends to rate convert everything to 
48k. Skype's codec is also 48k based as is the html standard Opus. As 
such, the analog part of the builtin audio hw is built using filters etc. 
that make 48k sound the best and let 44.1 fall where it may. CDs are still 
around, but music distribution has moved to Download based and streaming 
so there is no longer really any reason to use 44.1k.

However, having said that. It is not worth arguing the point. I suspect if 
we asked for the default to be changed we would be told "no". That is what 
I was told in pulseaudio btw. There are some laptops who's mic are 48k 
only, but the HDA chipset allows the OS to set other speeds and so the 
input has pops and crackles untill pulse is set to 48k default.

Len Ovens

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