[PD] pd latency on puredyne 9.10 with Nvidia HDA

Billy Stiltner billy.stiltner at gmail.com
Sun Mar 27 00:19:56 CET 2011

On 3/26/11, ailo <ailo.at at gmail.com> wrote:
> Sounds like you have an interesting problem with your nvidia sound device.
> Is the audio device a part of a graphic card by any chance?
> Sounds like the graphics is interferring with the audio device, though
> on puredyne the rtirq-init script together with the realtime kernel
> should give higher priority to the audio device even when sharing irq
> with other devices, if this is the source of your problem.
> Perhaps Alsa would be interested to know of this problem? You could
> subscribe to their mail list and let them know.
> Here are the Creative Labs devices supported by Alsa:
> http://www.alsa-project.org/main/index.php/Matrix:Vendor-Creative_Labs

Thanks ailo for the link. I'm not sure if the audio card is seperate
from the video and ethernet chip or not but they are all built into
the motherboard. I'm going to look into the machine later. I could not
find any info about the sound device from the computer manufacturere.
Windows just lists the device as HD audio.

Yes I will check the alsa forums. I thought someone else on this list
might have encountered the problem before. It is odd that only
interaction with pd's gui objects causes the glitching and interaction
with other windows does not. I still haven't tracked down the problem.

I think the sound device has it's own irq and is not shared with anything.

I'll have to check the device confiuration in vista and somehow match
it on linux.
I noticed in the pd config file there are settings for which audio
device to use.

On another note I/O latency measured with MAX on Vista is 30 ms. I
guess that is due to the 256 byte framebuffer and ASIO matching it's
buffer to max's. I'm sure it is less with pd. It sure doesn't sound
like 30ms though there is a definite delay when playing with the
example fm synth.

perhaps a rewriting of tcl/tks  gui rendering to use hardware
acceleration would help.

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