Author Topic: Crackling/popping audio in KDE...  (Read 1050 times)

colinjones

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Crackling/popping audio in KDE...
« on: September 10, 2008, 01:30:24 am »
Time to ask this question again, as i never got anywhere last time!

Since 0710 (can't remember which version, but probably at least since B3), whenever I start KDE, the intro sound is all crackly, sounds like it is being repeatedly gated rather than over driven. Doesn't effect LMCE at all. Gut feeling is that 2 different things are fighting for the device...

Til now I have just ignored it - although I have posted about it before, and at least 1 or 2 others were seeing exactly the same thing - because it was just for KDE. Now, however, I am playing some games in KDE (Tremulous, Nexuiz, Vega Strike and OpenArena) and at least Trem & OA the sound is terrible - sometimes it starts up silent, other times the sound is off most of the time and occasionally pops back for a snatch of music or an effect, other times, (esp during the game splash screens) it sounds crackly just like the KDE intro sound.

Vega Strike and Nexiuz sound far better (not sure yet if the issues with those are just heavy game play sound drops) and I note that Trem and OA I believe use the same game engine (Q3?) and both talk about OpenAL (sound? but how is this different from alsa?)

I have posted on those forums as well, but just wondering if anybody here has any suggestions on what could be causing the problem? I feel that if I can solve the KDE sound problem that this will likely solve the sound problem in these games as well...

MarcoZan

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Re: Crackling/popping audio in KDE...
« Reply #1 on: September 10, 2008, 09:35:24 am »
Hi colinjones

I have similar issue with my VIA EPIA M10000 MD, but in my case sound is crappy also with LMCE.

I've made some tests and I came to the conclusion that I don't think this issue is related to KDE itself (at least in my case, but likely also in yours).
What I made was to play the very same mp3 set (locally stored) in various situations: LMCE, KDE desktop (LMCE) and KDE from a plain Kubuntu 7.10 livecd.

It turned out that when playing from KDE - livecd the sound is cristal clear, while in the remaining situations the sound is clicking/bumping (don't know how to exactly describe in english).

Note that when you fire up a Kubuntu livecd you cannot play mp3 out of the box, but you are supposed to install some restricted packages. If I remember well you have to basically get ffmpeg and libxine1.
With stock Kubuntu you simply use adept and you're done, with LMCE you are not allowed to do so because all updates are driven via script to avoid breaking some LMCE dependecies.

In particular libxine1 is heavily customized, and I think that at least in my case this somehow fights with my MD hardware.

So KDE is not the nasty one ....

What I suggest is to try similar tests in your environment, and see what comes out.

In my case I've given up, as VIA MD is a bit old and plans are to replace it with some ATOM based hardware and demote VIA to simple MythTV client.
Of course I wouldn't mind to have it working fine also under LMCE, but for the time beeing I'm clueless.

HTH
Marco

colinjones

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Re: Crackling/popping audio in KDE...
« Reply #2 on: September 10, 2008, 03:34:27 pm »
Sorry Marco, this is a different issue. There is nothing wrong with my audio in LMCE, I have played many hundreds of hours of media perfectly in LMCE. Kubuntu on its own is fine, there is something with the two of them causing a problem...

Crumble

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Re: Crackling/popping audio in KDE...
« Reply #3 on: September 10, 2008, 03:58:48 pm »
well, when i want to make that kind of sound when producing music there is only way of doing it that i know of.  Cross electrical signals, easiest way is to do something stupid to a ground wire or find a way to lightly mingle the positive and negative.  Is there any chance that it could be an external probelm?  If not the only other (accidental)way ive ever seen that happen is drivers are pushing the card so hard on volume that it clips giving you a crackling sound, the only fix ive seen is new drivers.  If thats the case try some generic drivers, you'll probably lose hd sound but that really can't be good for the sound card anyway. 


Crumble

colinjones

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Re: Crackling/popping audio in KDE...
« Reply #4 on: September 11, 2008, 08:50:47 am »
Crumble - absolutely no chance of the first option, nothing is remotely analogue or electrical in my audio path until it gets to my amp's DAC. This is definitely happening inside the core.

We have already looked into clipping as you are right it does sounds somewhat similar, however its not that either as it is 1) randomly scattered in the sound with no association to sound level at the time and 2) there is no difference between the audio level during the problem and when there is no problem in lmce and 3) no change when you reduce the levels...



rodercot

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Re: Crackling/popping audio in KDE...
« Reply #5 on: September 11, 2008, 12:02:03 pm »
Colin,

 Have you looked into this on the Ubuntu Forums. It could be something not compiled in or missing for your driver in the kernel module, as i said before mine did this on the M2N-SLI and the M2N-PV-VM board BUT only the first time I entered KDE after a new setup and from then on it was fine. I really do not know how to explain. I cannot see as it would be two systems fighting for the card unless you were actually playing a media file at the time you open KDE and it did not get released and really I am not sure how Linux handles that problem but in windows you would get a segment or page fault I would think but I do know in windows if I have for instance a certain ripping program open it take all my sound resources and I get NO sound from any other software app while that one is open WITH no errors.

 Have you tried the latest binaries for alsa I think they are up to 1.0.17 now or you could even just recompile your driver from the 1.0.17 source and try it.

 What card is it you are using - Sorry if I missed that I take it you are using Spdif output, One thing to check as well is that sometimes I have read that the master Volume levels in alsa get tied to the headphone channel and there is quirk fix for this but I think that is with the snd_intel driver. But I am sure it would  or could affect other cards as well. 

 Dave