[Freebob-devel] [linux-audio-user] Focusrite Saffire Pro 26 I/O

[Daniel Wagner]

Pieter Palmers wrote:
> Richard Taylor wrote:
>> Good news and bad news. Good news, recording does work.
>> Bad news, zero latency monitoring comes on by default and routes
>> itself to all the analog outputs so it's a bit useless really.
>> Maybe there's a setting somewhere i've missed - definately nothing
>> connected in jack tho.
> There might be a chance that the device remembers the last mixer setting 
> on startup. So you what you can try is setting the mixer on a windows 
> machine (if you have one available) and see if it's settings are 
> retained on power cycles. The other option is to wait until we finish 
> the mixer control. I know that the current code already contains most of 
> the infrastructure to support this, but it's not finished. The 
> difficulty (and opportunity) is that the interface is the same for all 
> bebob devices, requiring it to be very flexible and hence pretty 
> complicated. Daniel is the expert on this, maybe he can shed a light 
> here. Maybe it's not very complicated to have a temporary tool that 
> kills all zero-latency monitoring paths.

Unfortunately, I'm not familiar with the Saffire. I can't tell if the
box remembers the settings through out. Each BeBoB device seems to be a 
bit different in respect to those things. Well, I guess this is called 
customization :)

We face two main problems. First, we want to support mixer settings. 
This can be achieved with a generic approach. The AV/C function block 
which represents the mixer is most likely a bridgeco extension. So we 
can write a generic piece of code for that.
Second, the additional switches and knobs etc which are [bridgeco's] 
customers extensions. Normally, they are controlled over proprietary 
AV/C extension or over the so called hispeed control interface, IRC. We 
need some support from the manufactures to tell us how to control those 
features and then we have to come up with some (generic?) control panel.

We have talked about the first problem and have agreed on some initial 
steps to achieve it. I will implement the AV/C stuff but that is the 
simple part. We (or better I) are still not sure how to abstract the 
generic interface. I remember some discussion here but can't remember 
the findings. Of course we need a GUI. We also got some inputs from lad 
where this problem of a generic mixer was also a topic. It seems that a 
form of a generic mixer is interesting for other projects besides freebob.

I haven't started to work on the mixer code since I'm still trying to 
figure out how to support the m-audio fw410. I reckon there are many 
users of fw410 around. The bad news is that it is rather broken device 
and it is difficult to get it working. There are some notes [1] about my 
undertaking but I don't know if this is worth spending more time on it. 
Anyway the next thing I will work on caching the AV/C models in order to 
speed up the device discovering. That means the mixer has to wait for a 
while if I'm doing this.

Apropos zero latency: There is no such thing as zero latency for a BeBoB 
device. You will always have a delay from the input to the output even 
though it is routed entirely through the device. I don't have the 
numbers and I can't tell if this is a problem or not but I just wanted 
to point that out before too many are really disappointed about that fact.

cheers,
daniel


[1] http://freebob.sourceforge.net/index.php/FW410