Sound mixer improvements

• Student: ChristosMargiolis (christos@)
• Mentor: HansPetterSelasky (hselasky@)

FreeBSD's default mixer utilities are not the best; mixer(8) is very basic and outdated, end users have to tweak sysctl(8) values to do simple things and programmers have to write DIY implementations for their programs (e.g audio/mixertui). This project aims to improve mixer handling for OSS on FreeBSD and make life for both programmers and users easier.

• A mixer(3) library.
  • Read all devices and knobs.
  • Extend knob capabilities:
    • 32-bit floating point left-right volume knobs.
    • Muting.
    • Recording input selector.
  • Select default sound card (not really a mixer feature, but really useful to have).
  • Provide as much information as possible about the mixer.
  • Use the more modern OSSv4's ioctls.
• Rewrite mixer(8).
  • Use mixer(3) and its new features.
  • Get rid of the old codebase completely.
  • Add more command line options.
  • Control-oriented interface like in sysctl(8).
• Implement some missing but useful for mixer(3) OSS ioctls in the kernel.
• Implement sound device playback/recording status sysctl.
• Update /etc/rc.d/mixer to work with the new version of mixer(8).
• Make /dev/sndstat “useless” by containing its information in the output of mixer(8).

• Panning capabilities in mixer(3), but it should be easy to write a DIY handler using the mix_ctl_t interface.

Since a new version of mixer(8) is one of the delievarables, it'll also serve as a testing ground for the library. Me and the mentor will also test the library with various sound devices we own.

• GitHub
• Sourcehut
• My own Git server

• mixer(3)
• mixer(8)

• sound(4) mute ioctls implementation (merged)
• sound(4) playback/recording mode sysctl implementation (merged)
• Final project review (merged)

• OSS 4.x Programmer's Guide
• sound(4)
• sysctl(8)
• mixerctl(8)