Handling Multi-Channel Audio Signals in Rust

Don't define containers,
define interfaces.

—Irish proverb

Nomenclature

TODO: "frame", "sample"

The term "planar" seems to originate from FFMPEG (which also seems to use the term "packed"). It is also used in Web Audio.

Potential Alternatives

In alphabetical order. Comments might be outdated (see version numbers in links).

• audio, formerly known as rotary
  • "dynamic", "interleaved", "sequential"
  • traits: Buf, BufMut, ...
• audioadapter and audioadapter-buffers
  • "interleaved", "sequential"
• audio-blocks
  • "planar", "sequential", "interleaved", "mono"
  • traits: AudioBlock, AudioBlockMut, Sample
• audio_buffer_interface
• audio-channel-buffer
  • not a lot of documentation, how are those buffers supposed to be passed around?
• audiochannelutils
  • free functions FTW!
  • a lot of Vecs in API
  • trait SampleType
• audio_samples
  • sample_rate: NonZeroU32
  • Interleaved, NonInterleaved
  • ChannelIterator
  • good documentation, but feature creep, many dependencies
• dasp, formerly known as sample
  • no block-wise processing, only frame-wise?

Existing APIs

It might be interesting to look at existing APIs to see which terms they use, which data types etc.

• CPAL
  • traits: Sample, ...
  • input/output streams with callbacks taking &[T] and &mut [T]
    • interleaved data (see also #367)
    • no duplex support yet (see #349 and #1096)
  • types:

    pub type ChannelCount = u16;
    pub type FrameCount = u32;
    pub type SampleRate = u32;
    pub enum BufferSize {
        Default,
        Fixed(FrameCount),
    }
    

  • parameter names:

    channels: ChannelCount
    sample_rate: SampleRate
    buffer_size: BufferSize