[LAD] Jack buffer management for block convolution

Gabriel M. Beddingfield gabrbedd at gmail.com
Thu Jun 10 13:35:49 UTC 2010


Hi Damien,

On Thu, 10 Jun 2010, Damien Zammit wrote:

> Hi,
>
> I have written a FFTW based block convolution jack client, but I am
> having difficulty processing the last jackframes%L samples of the jack
> buffer.  I have read that it might be an idea to collect the samples

What do you mean by "the last jackframes%L samples" ??

The process() callback tells you to process nFrames samples. 
Are you wanting to access the samples the preceeded this? 
If so, you'll need to store them somewhere yourself.  Jack 
doesn't store them.

> into a second buffer and process them independently of the jack
> process callback, but I have no clue how to implement that.  Any
> suggestions would be appreciated.

You don't necc. need to process them independently of the 
jack callback.  However, you will need to create your own 
buffer to store your data.

However, if your calculations can't be done within a single 
process() callback without taking too long, then you will 
either need to break up your calculation so that it will fit 
(time-wise) into the process() callback.  If you can't do 
that, then you /will/ need to process them independently of 
the jack callback.

-gabriel



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