[Ardour-Dev] Fwd: [Ardour-Cvs] Ardour source branch meterbridge updated. 3.2-153-gf885622

[Robin Gareus]

On 07/06/2013 10:48 PM, Jörn Nettingsmeier wrote:
[..]

> within a digital audio system based on floats, i don't have to care
> about peaks at all. 

You will want to know if a signal on the input is clipping.

> only at the last step before going back to
> fixed-point or analog do i have to adjust.

Yes, that too :)

> so all i want to see from a peak indicator is "has my data been clipped
> at some earlier point in the chain?". i don't really care about
> inter-sample peaks at this stage.
> 
> fwiw, the current implementation in ardour is not foolproof either:

Ow, that's bad.

> when i overload my micstasies, the peak indicator will show 0.0dB but
> not turn red

It will only turn red when the absolute signal value is >= 1.0.
(now this value is configurable).

> so i've learned to look for the numbers rather than the
> color. of course, it could also be that the preamp does not ever deliver
> fullscale for some reason...

Can it be that the Micstasy uses integer PCM and never produces a peak?
e.g with 16-bit audio it sends 2^15 -1 rather than 2^15. That rounds to
-0.0dB but is still less than 1.0 in jack.

>> Either way this is not relevant yet. The meterbridge branch (which will
>> be merged back to master soonish) is currently mostly concerned with GUI
>> - not the actual calculations.
> 
> i see.

It is related, because the peak-display logic is currently implemented
in the GUI (only level-calculation and peak-hold is done in the
audio-thread).


[..]
> btw, i should have written to you about it, but i've been using the
> video timeline for a little project last week (usual workflow: video guy
> decides edits and delivers the final video with rudimentary guide track
> from built-in mics).

That's exactly the envisaged work-flow.

> worked like a charm, thanks a lot!

It's great to hear success stories rather than bug-reports for a change.
Keep them coming!

Cheers!
robin