Mike Melanson—a primary author of the Linux Flash plugin, xine, ffmpeg, and a general crazy-good multimedia hacker—on the state of Linux Audio APIs:

There are 2 primary methods of sending audio data to a DAC under Linux: OSS and ALSA. OSS came first; ALSA supplanted OSS. Despite this, and as stated above, there are numerous different ways to do the DAC send. There are libraries and frameworks that live at a higher level than OSS and ALSA. In the end, they all just send the data out through OSS or ALSA.

The zaniest part is that some of these higher level libraries can call each other, sometimes in a circular manner. Library A supports sending audio through both OSS and ALSA, and library B does the same. But then library A also has a wrapper to send audio through library B and vice versa. For that matter, OSS and ALSA both have emulation layers for each other. I took the time to map out all of the various libraries that I know of that operate on Linux and are capable of nudging that PCM data out to a DAC:

Barry Schwartz would be shaking his head, methinks. And yes, I’m well aware of efforts to unify this mess. That doesn’t excuse that this jungle has been the state of Linux audio for the past ten years. I love the comments too: instead of admitting how dumbass this is, they give suggestions for using even more APIs (“try KDE4’s Phonon! That’ll fix everything!”)… totally missing the amusing irony, and also missing the point that Mike needs something that works on as many Linux distributions as possible.