5 Aug
2007
5 Aug
'07
12:09 a.m.
Hi,
There was a thread on LAD two years ago, almost exactly, pointing out
the denormal problems in TAP's EQ plugins:
http://linuxaudio.org/pipermail/linux-audio-dev/2005-August/013367.html
Unfortunately the problem was never fixed. Many people are still having
issues with 'TAP Equalizer' and 'TAP Equalizer/BW', as there are recent
posts in ardour-users regarding spiralling CPU usage for DSP.
I've been doing my best to debug and fix the problem, but now that I
actually want to reproduce the problem, I can't! I can't reproduce the
jump in CPU usage, although I suffer a loss of audio in Ardour when I
have many TAP EQ's running in a session.
So, I tried a few small changes to tap-plugins-0.7.0 which seemed to fix
the loss of audio. If anyone can reliably reproduce the jump in CPU
usage (which usually triggered by periods of silence in the middle of a
recording), then please try rebuilding the TAP plugins from source, with
and without my attached patch, and see if it helps.
Please note, if your current tap_eq.so and tap_eqbw.so are already
installed in /usr/lib/ladspa/, you may need to edit the Makefile and
remove "local/" from the .so and .rdf install paths.
I'm hopeful that this might cure denormal problems that some people have
suffered from with these plugins for years. If this works, I will test
many more plugins for the same problem and perhaps fix those, too.
Thanks!
--
Steven Chamberlain
steven(a)pyro.eu.org
5 Aug
5 Aug
1:22 a.m.
I completely rewrote tap eq while on vacation last month to be pure sse2,
using doubles for extra resolution, with no denormal problems, and, at least
on x86_64, far greater speed, especially for the stereo version. The changes
were so extensive as to require a new plugin number, which these have. I'm
not settled on the name, but...
See http://www.taht.net/~mtaht/ <http://www.taht.net/%7Em>mdp.tgz for a
snapshot.
I have tested extensively on my own machine but have not cleaned up the code
enough to justify a formal release, perhaps our efforts can be synced....
On 8/4/07, Steven Chamberlain <steven(a)pyro.eu.org> wrote:
Hi,
There was a thread on LAD two years ago, almost exactly, pointing out
the denormal problems in TAP's EQ plugins:
http://linuxaudio.org/pipermail/linux-audio-dev/2005-August/013367.html
Unfortunately the problem was never fixed. Many people are still having
issues with 'TAP Equalizer' and 'TAP Equalizer/BW', as there are recent
posts in ardour-users regarding spiralling CPU usage for DSP.
I've been doing my best to debug and fix the problem, but now that I
actually want to reproduce the problem, I can't! I can't reproduce the
jump in CPU usage, although I suffer a loss of audio in Ardour when I
have many TAP EQ's running in a session.
So, I tried a few small changes to tap-plugins-0.7.0 which seemed to fix
the loss of audio. If anyone can reliably reproduce the jump in CPU
usage (which usually triggered by periods of silence in the middle of a
recording), then please try rebuilding the TAP plugins from source, with
and without my attached patch, and see if it helps.
Please note, if your current tap_eq.so and tap_eqbw.so are already
installed in /usr/lib/ladspa/, you may need to edit the Makefile and
remove "local/" from the .so and .rdf install paths.
I'm hopeful that this might cure denormal problems that some people have
suffered from with these plugins for years. If this works, I will test
many more plugins for the same problem and perhaps fix those, too.
Thanks!
--
Steven Chamberlain
steven(a)pyro.eu.org
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--
Michael David Taht
PostCards From the Bleeding Edge
http://the-edge.blogspot.com
5:33 p.m.
Mike Taht wrote:
I completely rewrote tap eq while on vacation last
month to be pure
sse2, using doubles for extra resolution, with no denormal problems,
and, at least on x86_64, far greater speed, especially for the stereo
version.
Excellent work, I was hoping someone would write an EQ plugin using SSE2
(I don't know of any existing ones).
I have tested extensively on my own machine but have
not cleaned up
the code enough to justify a formal release, perhaps our efforts can
be synced....
My own 'efforts' don't amount to much so far, but I'm working on a
test-bed to analyse LADSPA plugins, and I can continue to monitor your
snapshots for any issues.
One bug I found so far, is that if I call run() with a block size of 1,
do_eq() is run with sample_count of 2. This causes the 'output' buffer
to be overrun inside of the switch(numfilt) block.
Also I have to ask whether both the original TAP plugins and your own,
should set HINT_LOGARITHMIC for the frequency and/or gain parameters?
And I'm not sure what msp_eq.c.good is for, maybe that wants deleting?
Anyway, please keep up the good work.
Paul Davis wrote:
you'd better make sure you turn off Ardour's
denormal protection if
you want to duplicate it. This was added to 2.0.3 IIRC.
That's a good point, but I had that turned off.
Regards,
--
Steven Chamberlain
steven(a)pyro.eu.org
2:35 p.m.
On Sun, 2007-08-05 at 03:09 +0100, Steven Chamberlain wrote:
Hi,
There was a thread on LAD two years ago, almost exactly, pointing out
the denormal problems in TAP's EQ plugins:
http://linuxaudio.org/pipermail/linux-audio-dev/2005-August/013367.html
Unfortunately the problem was never fixed. Many people are still having
issues with 'TAP Equalizer' and 'TAP Equalizer/BW', as there are recent
posts in ardour-users regarding spiralling CPU usage for DSP.
I've been doing my best to debug and fix the problem, but now that I
actually want to reproduce the problem, I can't!
you'd better make sure you turn off Ardour's denormal protection if you
want to duplicate it. This was added to 2.0.3 IIRC.
--p
6646
days inactive
6647
days old
linux-audio-dev@lists.linuxaudio.org
3 comments
3 participants
participants (3)
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Mike Taht -
Paul Davis -
Steven Chamberlain