1 Oct
2010
1 Oct
'10
12:45 a.m.
On 09/30/10 22:41, Philipp Überbacher wrote:
Excerpts from Robin Gareus's message of 2010-09-30
16:21:27 +0200:
Aww sorry. I saw this too late.
The film I intended to watch was too boring so..
git clone git://rg42.org/paulstretch
cd paulstretch
./compile_linux_fftw_jack.sh
or get a diff:
http://rg42.org/gitweb/?p=paulstretch.git;a=commitdiff_plain;hp=upstream;h=…
There's still quite a few things to do. besides: it's a quick hack and
far from optimal:
- It currently only opens the JACK clients if it's playing.
(after stop the port-connections are lost)
- It auto-connects the jack-ports to the first two available outputs
(unless you remove the -DENABLE_AUTOCONNECT_JACK compile option)
- it does not do any resampling
(but prints a warning if the samplerates mismatch and plays anyway)
- it does not add a ringbuffer.
(it may cause x-runs)
So you can take this as inspiration :)
Using a jack_ringbuffer is actually not that hard, have a look at the
jack_capture.c example client (comes with the jackd source).
Resampling with libsamplerate is not very complicated, although I'm sure
you'll have to work out a few things if you do it the first time (it's a
good learning experience - google for "secret rabbit code".
OTOH I'm not convinced that the paulstrech player needs anyway. It may
be a nice add-on feature though.
Hint: for both ringbuffer and/or resampling you'll want to add a new
function to Player.cpp that basically does the same as
void Player::getaudiobuffer(int nsamples, float *out)
I suggest
getaudiobuffer_channel(int nsamples, int channel, float *out)
Contact Paul and Alan Calvin :)
Cheers!
robin
On 09/30/10 13:35, Louigi Verona wrote:
I'd be interested.
It would likely take me some time though, and maybe some guidance, but
it's something I want to learn. I dabbled in C but can only read simple
code. I start to study computer science next week, which will give me
access to the library at least, to K&R and a bunch of others.
The lectures at university are mostly in java but C is required at some
point, and I guess it's better to start learning it sooner rather than
later, besides, it seems to be needed for all the neat audio stuff ;)
So yeah, I guess I should get the code, put it in a git repo and just
start hacking... As for JACK support.... would anyone be
interested in adding it, if it is
trivial? Would love to have it in my audio chain.
At second glance: it's not going to be that easy. The built-in player
makes use of mutex-locks which would need to be replaced with a
[lock-free] ringbuffer (Adding JACK I/O is still trivial but without
lock-free buffers paulstrech would be able to block jack-processing and
cause x-runs).
That'd be a good job for someone who wants to get started with JACK and
C/C++ programming.