DSP(7)

📦
version 4.2-build2020 · 3 versions
, in ubuntu noble

💖 dsp — Open Sound System audio devices 💖

okay bestie, welcome to dsp(7), the page that explains where your sound actually lives on an Open Sound System box. pull up a chair, grab a boba, we're getting into it 🧋✨

🌸 NAME 🌸

dsp — Open Sound System audio devices

✨ DESCRIPTION ✨

/dev/dsp is the default audio device in the system, periodt. it's wired up to your main speakers and to the primary recording source (think: your microphone). your system administrator can set /dev/dsp to be a symbolic link pointing at whatever default device they want. and if you're like "okay but what devices do I even have" — the ossinfo utility lists the available audio devices in the system. slay.

then there's the squad of special-purpose defaults: /dev/dsp_mmap, /dev/dsp_ac3, /dev/dsp_multich and /dev/dsp_spdifout are default audio devices for specific applications such as games or media (DVD) players. different vibes, different files 🦋

🌈 DIRECT ACCESS AUDIO DEVICE FILES 🌈

OSS 4.0 (and later) will create audio devices under the /dev/oss/<device> directory. example? /dev/oss/sblive0/pcm0 is the first audio device that belongs to the first Sound Blaster Live! or Audigy card in the system. iconic. these direct devices are the ones you reach for when an application needs to access a specific audio device (instead of the default one).

you can use the ossinfo(1) utility with the -a option to get a list of the available audio devices in the system. go look, it's giving inventory 💅

🎀 LEGACY AUDIO DEVICE FILES 🎀

traditionally OSS has created device files like /dev/dsp0 to /dev/dspN for each audio device in the system. OSS 4.0 still supports this legacy naming — no cap. these files are symbolic links to the actual device files located under /dev/oss. the ossdevlinks(8) utility is used to manage these links and it will be automatically invoked when OSS is started. it just does it. main character energy fr fr.

👑 COMPATIBILITY 👑

  • The /dev/dsp (default() audio device file will be supported by all OSS implementations and versions.
  • The special purpose audio default devices (such as /dev/dsp_mmap) are only supported by OSS 4.0 and later.
  • The legacy audio device files (such as /dev/dsp1) are supported by all OSS versions and implementations.
  • New style audio device files (under /dev/oss) are only supported by OSS 4.0 and later. However some independent OSS implementations may only support the legacy naming even they are otherwise OSS 4.0 compatible.
  • /dev/dsp0 doesn't exist in all Linux systems which use /dev/dsp for the same purpose. In such systems /dev/dsp points to the first audio device and /dev/dsp1 to the second.
lowkey important bestie: don't assume /dev/dsp0 is just there on every Linux box. check before you hardcode, iykyk 🙈

🧚 PROGRAMMING INFORMATION 🧚

See the Audio Programming section of the OSS Programmer's Guide (DSP(2)) for more info. that's the deep lore if you wanna write code against this 💜

💅 OPTIONS 💅

None

(yeah. nothing. zero. the options section said no options and we respect that. not everything needs a flag 🌸)

🍓 FILES 🍓

  • /dev/dsp
    • Default audio device
  • /dev/dsp_mmap
    • Default audio device for applications using mmap(2)
  • /dev/dsp_ac3
    • Default audio device for applications sending Dolby Digital (AC3) audio to an external receiver.
  • /dev/dsp_multich
    • Default multichannel (4.0-7.1) audio output device
  • /dev/dsp_spdifout
    • Default digital audio (S/PDIF) output device
  • /dev/oss/<driver>/pcmN
    • Direct access device files for individual audio devices.
  • /dev/dsp0 to /dev/dspN
    • Legacy style direct access audio device files.

⭐ AUTHOR ⭐

4Front Technologies

and that's the whole page bestie 🫶 written by 4Front Technologies, under the OSS Devices umbrella, dated 7(11 February 2015) — go forth and make some noise 🔥🎧

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