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Change in internal audio behavior re: bit perfect audio

Posted: 28 Feb 2009 07:26
by 1audio
I just upgraded VLC to the version Ubuntu 8.10 just made available. In the process one of the key features I was using VLC for has changed. Before I could get it to pass 24 bit audio at different sample rates to the spdif output unchanged, "bit perfect" a feature I want since my audio hardware has special capabilities that are dependent on bit perfect audio. The new version, VLC version 0.9.4 Grishenko, has changed how this works and I cannot get it to pass the audio without changing the level. In the process its changing the audio stream and affecting it. I have tried every setting I could find and none will restore the operation I had.

Is this change intentional? Is there a way to pass the stream through unchanged? How to I revert to the previous version?

Re: Change in internal audio behavior re: bit perfect audio

Posted: 28 Feb 2009 14:02
by Jean-Baptiste Kempf
Are you sure the issue is not about PulseAudio being the default output on ubuntu?

Re: Change in internal audio behavior re: bit perfect audio

Posted: 28 Feb 2009 14:55
by 1audio
It could be, however it was an update to VLC that triggered the change. I am trying to remove pulseaudio or at least disconnect it where I can. Any suggestions?

Re: Change in internal audio behavior re: bit perfect audio

Posted: 28 Feb 2009 15:09
by Jean-Baptiste Kempf
try to force alsa output in VLC prefs.

Re: Change in internal audio behavior re: bit perfect audio

Posted: 28 Feb 2009 16:30
by 1audio
I have tried every option. I'm running Ubuntu Studio 8.10. It was working with the output set to the direct hardware: esi juli@ ice1724, hw0,1. however that isn't working at all and default is goiung to the hardware but via some level control. The hardware mixer doesn't touch the stream going out the spdif port so I'm not sure where the level control is coming from.
Something changed with the update and I saw the same change on two separate machines with the same update. They both report VLC 0.9.4 Grishenko. I see that isn't even the most recent version. I could install the latest if that might give some insight.

Re: Change in internal audio behavior re: bit perfect audio

Posted: 01 Mar 2009 17:03
by 1audio
I just built VLC from git and this issue has not changed. If I select the hardware output from the setup screen I get no output. If I select default I get the output and a software volume control from somewhere. This doesn't seem correct and may be a bug but I can't tell.

Re: Change in internal audio behavior re: bit perfect audio

Posted: 02 Mar 2009 05:19
by jalles
It is not likely that this is a VLC issue (like j-b said).

You should probably read and understand this:

http://ubuntuforums.org/showthread.php?p=4928900

My guess is, what you were doing before was a glitch, and it is now fixed :?

To do what you want, it might be better to not run Studio. (Install clean Intrepid).

Or, maybe you maybe can find a way through a wrapper, google and check forums about PulseAudio.

good luck,

Jim

P.S. what is the audio hardware?