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Author Topic: Linux Audio System Discussion (Dev Talk)  (Read 4691 times)

InflatableMouse

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Linux Audio System Discussion (Dev Talk)
« on: August 01, 2013, 01:43:22 am »

Awesome. Really looking forward to see what you're coming up with!

But I also wonder what you will do about the sound system on linux. By default many distributions come with PulseAudio which is, well .. crap ... and that's an understatement!

Default configs are on 44/16 and resample everything (quite badly too IMO). There is no exclusive mode as far as I'm aware and many distros get in trouble if you try to adjust the default config. For instance, when I tried to edit daemon.conf (PA's config) to adjust it to 96/24 (which really, is just 2 words and restart PA), I lost my left channel. When I reverted the config file the left channel did not return.

Other annoyances I had was that apparently the option to switch outputs (from main to headphones for example) is not always available, it depended on the shell I was running (Gnome, KDE, etc). I figured it was just a missing applet and the audio layer was still able to, but from all the programs I've seen and tried on linux, none offered options which were not available to me in the OS itself. Ie, none offered 24-bit output or sample frequencies higher than what PA was set to, none offered exclusive modes and none were able to switch outputs if the OS wasn't able to.

There are some distros that seem to be able to properly output audio without resampling, but these are dedicated for that purpose. XBMC's OpenELEC is one.

Or maybe you can completely bypass PA/Alsa, probe hardware and access it directly? I don't know ... or ... :)

How cool would it be if you would make an appliance-like version? A Linux distro stripped to the bone and dedicated to only run JRiver Media Center, like some forks of XBMC (OpenELEC). It comes without a GUI and boots straight to the application. If you want to do anything, you need to enable SSH and remote shell into it.
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Hendrik

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Re: Linux Audio System Discussion (Dev Talk)
« Reply #1 on: August 01, 2013, 02:01:27 am »

But I also wonder what you will do about the sound system on linux. By default many distributions come with PulseAudio which is, well .. crap ... and that's an understatement!

The usual tool for "Pro-Audio" is JACK (on top of ALSA), however MC will still have to find a way to free the audio device from PA (ie. by calling pasuspender), since the ALSA devices by default are always exclusive access, and if PA blocks that, its no good. :)
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InflatableMouse

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Re: Linux Audio System Discussion (Dev Talk)
« Reply #2 on: August 01, 2013, 02:16:58 am »

Yeah, JACK seems good but I don't think it can or is meant to replace PulseAudio. Never got around to try it out. when I tried to apt-get remove pulseaudio it wanted to remove half my system including xserver so I figured I'd best answer No. Good thing it asked.

This weekend though I got so frustrated with my Linux install I completely wiped it from my system. Maybe I should reinstall it ::)  ;D.
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Hendrik

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Re: Linux Audio System Discussion (Dev Talk)
« Reply #3 on: August 01, 2013, 03:02:34 am »

Yeah, JACK seems good but I don't think it can or is meant to replace PulseAudio.

No, they don't both do the same thing, luckily you can install both in parallel, just cannot run both on the same audio device at the same time (so you have to suspend PA first)
JACK is really aimed at "Pro Audio" applications, and PA is aimed at a desktop audio usage with built in mixing and everything, a bit like DirectSound acts, just worse.
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xynoe44

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Re: Linux Audio System Discussion (Dev Talk)
« Reply #4 on: August 01, 2013, 03:40:39 am »

Linux version??? Coooool  8)

Awesome. Really looking forward to see what you're coming up with!

But I also wonder what you will do about the sound system on linux. By default many distributions come with PulseAudio which is, well .. crap ... and that's an understatement!

Default configs are on 44/16 and resample everything (quite badly too IMO). There is no exclusive mode as far as I'm aware and many distros get in trouble if you try to adjust the default config. For instance, when I tried to edit daemon.conf (PA's config) to adjust it to 96/24 (which really, is just 2 words and restart PA), I lost my left channel. When I reverted the config file the left channel did not return.

Other annoyances I had was that apparently the option to switch outputs (from main to headphones for example) is not always available, it depended on the shell I was running (Gnome, KDE, etc). I figured it was just a missing applet and the audio layer was still able to, but from all the programs I've seen and tried on linux, none offered options which were not available to me in the OS itself. Ie, none offered 24-bit output or sample frequencies higher than what PA was set to, none offered exclusive modes and none were able to switch outputs if the OS wasn't able to.

There are some distros that seem to be able to properly output audio without resampling, but these are dedicated for that purpose. XBMC's OpenELEC is one.

Or maybe you can completely bypass PA/Alsa, probe hardware and access it directly? I don't know ... or ... :

How cool would it be if you would make an appliance-like version? A Linux distro stripped to the bone and dedicated to only run JRiver Media Center, like some forks of XBMC (OpenELEC). It comes without a GUI and boots straight to the application. If you want to do anything, you need to enable SSH and remote shell into it.


Alsa, by default and design, works in exclusive mode and is bit perfect if you output directly to hardware device (hw:x,y). Far easier than windows or any other OS.  ;D Thus no reason to mess with any sound server.
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dean70

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Re: Linux Audio System Discussion (Dev Talk)
« Reply #5 on: August 01, 2013, 05:02:43 pm »

Look at something like Ubuntu Studio which is tailored for audio work. Maybe even as a custom distro?
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ths61

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Re: Linux Audio System Discussion (Dev Talk)
« Reply #6 on: August 03, 2013, 11:14:43 pm »


How cool would it be if you would make an appliance-like version? A Linux distro stripped to the bone and dedicated to only run JRiver Media Center, like some forks of XBMC (OpenELEC). It comes without a GUI and boots straight to the application. If you want to do anything, you need to enable SSH and remote shell into it.


Add to that the ability to boot into Linux run level 3 (console text mode, with no GUI overhead) to run the server and player on a headless system to be controlled remotely. 

Booting back into run level 5 would allow the GUI and configuration screens.
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