20 Jun
2015
20 Jun
'15
7:20 p.m.
I want to write a small audio signal processing application.
What I want to do is to successive blocks of N samples,
process them and display the results in real time.
The processing takes a lot more time than sampling interval,
however it can be comfortably done in the time it takes to
collect N samples. That is why I like to have an arrangement
where I can queue two or three buffers for audio input and
process the first full buffer in plenty of time while the audio
software is filling in the next buffer. As soon as I finish
processing the buffer, I could queue it to be filled again.
I would also like use callbacks as much as possible.
I have tried PORTAUDIO and it does not seem to do multi-buffering
I have tried JACK briefly but it suffers from lack of documentation and
as far as I could gather it had no facilities for this kind of thing.
I know I could write a higher level interface for PORTAUDIO
to simulate multi-buffering but it means I have to copy input buffer into
intermediate buffers to simulate multi-buffering and apart from
synchronisation problems that I may encounter, it is a solution
that appears very inelegant to me.
Is there anything out there which can do multi-buffer audio I/O ?
Any pointers to web pages, advice or admonition is very welcome!
21 Jun
21 Jun
1:36 p.m.
JACK is exactly designed for this use case. The documentation is bit hard to get from a
beginner's perspective, but there are of sample apps that you can look at in the JACK
distribution.
Basically all audio processing in Linux is done on a buffer-by-buffer basis with a
several-buffer queue. You need to do nothing to get that, it's just the way the
underlying system works.
Thanks,
Bill Gribble
On Jun 20, 2015, at 13:21, mehrdad ghassempoory
<ghassempoory(a)gmail.com> wrote:
I want to write a small audio signal processing application.
What I want to do is to successive blocks of N samples,
process them and display the results in real time.
The processing takes a lot more time than sampling interval,
however it can be comfortably done in the time it takes to
collect N samples. That is why I like to have an arrangement
where I can queue two or three buffers for audio input and
process the first full buffer in plenty of time while the audio
software is filling in the next buffer. As soon as I finish
processing the buffer, I could queue it to be filled again.
I would also like use callbacks as much as possible.
I have tried PORTAUDIO and it does not seem to do multi-buffering
I have tried JACK briefly but it suffers from lack of documentation and
as far as I could gather it had no facilities for this kind of thing.
I know I could write a higher level interface for PORTAUDIO
to simulate multi-buffering but it means I have to copy input buffer into
intermediate buffers to simulate multi-buffering and apart from
synchronisation problems that I may encounter, it is a solution
that appears very inelegant to me.
Is there anything out there which can do multi-buffer audio I/O ?
Any pointers to web pages, advice or admonition is very welcome!
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6:55 p.m.
On Sun, Jun 21, 2015 at 7:35 AM, Bill Gribble <grib(a)billgribble.com> wrote:
Basically all audio processing in Linux is done on a buffer-by-buffer
basis with a several-buffer queue. You need to do nothing to get that,
it's just the way the underlying system works.
s/Linux/all general purpose operating systems, all plugin APIs, most well
known audio I/O APIs/
basically, EVERYTHING works this way. You get a buffer's worth of
data/space to read/write while the other buffer is being recorded/played.
You get told to work with a buffer, you don't get to decide when.
ALSA and JACK add an additional wrinkle that it is possible to configure
for more than 2 buffers, but in general, with a well designed audio
interface and reasonably sensible motherboards, there's never a
particularly good reason for d
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participants (3)
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Bill Gribble -
mehrdad ghassempoory -
Paul Davis