PipeWire: The Linux audio/video bus [LWN.net]

PipeWire: The Linux audio/video bus

Posted Mar 3, 2021 15:47 UTC (Wed) by chris_se (subscriber, #99706)
In reply to: PipeWire: The Linux audio/video bus by ms-tg
Parent article: PipeWire: The Linux audio/video bus

> Am I misremembering, or wasn’t the prior state that we would have apps crash with “could not open ...” if two apps were trying to make sound at once?

All of the other "sound servers", such as aRts and ESD, were created just for this reason. For programs that weren't compatible with them (basically anything not KDE / not GNOME) you had to start them with a wrapper that used a LD_PRELOAD library to hijack the system calls to open the ALSA/OSS devices, and reroute that through aRts/ESD -- but that didn't work with all software, so you had to kill the sound servers sometimes to use some applications. And then others using the sound server would misbehave. And don't get me started with Suspend-to-RAM, which typically killed any application that was currently outputting audio when closing your laptop lid...

I do remember ALSA having native software mixing, but from what I recall it required all applications to use the same sample rate for their audio, which of course was often not really the case. (Maybe that's changed in the mean time?) And you had to configure it manually in your ~/.asoundrc. Also, I don't know exact time this was added, but I remember seeing ALSA software mixing for the first time when PulseAudio was already a thing, so maybe it came way too late. Or at the very least it wasn't advertised very well, because I didn't read about it before I was already switching to PulseAudio.

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PipeWire: The Linux audio/video bus

Posted Mar 3, 2021 19:32 UTC (Wed) by dezgeg (guest, #92243) [Link] (5 responses)

At least my personal recollection is that there was a period where ALSA software mixing (without any tweaking of .asoundrc or anything on most distros) was working very well, better than PulseAudio - as in, many audio problems could be solved by a "killall pulseaudio" (I do not remember if root was required for this or not).

However this was long time (years) ago, definitely before me owning any USB or Bluetooth exclusive audio devices. I do not even remember when "killall pulseaudio" last solved anything And regardless of that being able to adjust sound levels per-application with PA has been very useful (lack of it is not show stopper but just very nice to have).

PipeWire: The Linux audio/video bus

Posted Mar 4, 2021 4:52 UTC (Thu) by jeltz (guest, #88600) [Link] (2 responses)

I still have to solve audio problems by killing PuleAudio (last time I did it was about 2 weeks ago), and as far as I know it coul always be done without superuser privileges. I am one of the minority who never have experienced PulseAudio becoming stable, it is better than ti was when I first used it but still quite unstable.

PipeWire: The Linux audio/video bus

Posted Mar 5, 2021 0:06 UTC (Fri) by hailfinger (subscriber, #76962) [Link] (1 responses)

Killing/restarting pulseaudio (pulseaudio -k) after a suspend-to-RAM is required and sufficient to get my USB webcam microphone working again in ~90% of my suspend cycles. That's a few times per day. I didn't bother reporting that because I've seen too many pulseaudio bug reports being dismissed along the lines of "pulseaudio is never buggy, it's the fault of your driver/application/whatever".

PipeWire seems to care about not breaking existing setups and the article implies that the community is nice. I'm happy about that and look forward to testing it.

PipeWire: The Linux audio/video bus

Posted Mar 5, 2021 5:56 UTC (Fri) by zdzichu (subscriber, #17118) [Link]

Not to defend PA, but it really smells like USB microphone driver problem. It seem not to handle suspend/resume cycle (while device is opened?).
If you do not report bugs, they won't be fixed. And you will have the same problem with pipewire.

PipeWire: The Linux audio/video bus

Posted Mar 4, 2021 15:45 UTC (Thu) by sorpigal (subscriber, #36106) [Link] (1 responses)

For whatever it's worth I still run purely ALSA with software mixing, including things like USB audio devices (just added a new mic yesterday), multiple applications playing audio at the same time, and everything Just Works with no issues. I do have a .asoundrc, but it's pretty boilerplate and I haven't had to change it in years. The only time I have audio trouble is when I need to run a program that only supports pulse (but there's apulse for that).

The only thing I occasionally pine for is per-process volume control.

PipeWire: The Linux audio/video bus

Posted Mar 18, 2021 9:20 UTC (Thu) by mgedmin (guest, #34497) [Link]

Is pure ALSA able to move a playing stream from one device to another (say, internal speakers to a Bluetooth headset)?

PipeWire: The Linux audio/video bus

Posted Mar 17, 2021 10:18 UTC (Wed) by immibis (subscriber, #105511) [Link]

I am not sure how things were "back then", but ALSA today has both rate conversion and mixing plugins. If you layer those in the right order, applications can output at different rates. Whether the default configuration does this or not is a different question.