saimx

01 Overview

Unlike Dolby Atmos, which encodes a bed plus channel differences, SAIMOX stores genuinely separate audio tracks that can be freely positioned and animated in 3D space.

Core principles

• Real objects. Each track is a discrete audio object — not an offset from a downmix.
• Codec-agnostic. Opus, FLAC, AAC or WAV, depending on the use case.
• Binaural fallback. An optional stereo bed for devices without spatial audio.
• Offline-first. Download, unpack, play — no streaming dependency.
• Cross-platform. iOS, macOS, Android and web compatible.
• License-free. No Dolby license, no patents, fully open.

02 Container

A .smx file is a renamed ZIP archive — like .docx, .epub or .apk.

# meditation.smx  (= ZIP archive)
├─ manifest.json          // required: format meta, codec info
├─ spatial.json           // required: tracks, movements, environment
├─ tracks/                // required: audio files
│   ├─ bed_left.opus      // optional: binaural fallback L
│   ├─ bed_right.opus     // optional: binaural fallback R
│   ├─ track_01.opus      // object track
│   └─ track_02.opus
├─ segments/              // optional: sparse audio chunks
└─ assets/                // optional: cover, waveforms

Compression: audio files are already compressed, so they're stored with STORE (no re-compression). JSON and assets use DEFLATE.

03 manifest.json

Global metadata about the package — title, duration, codec and an integrity checksum.

{
  "saimox_version": "1.0",
  "package": {
    "title": "Ocean Meditation",
    "duration": 300.0,
    "category": "meditation",
    "license": "CC-BY-4.0"
  },
  "audio": {
    "codec": "opus",
    "sample_rate": 48000,
    "channels_per_track": 1,
    "total_tracks": 5
  },
  "compatibility": { "binaural_fallback": true }
}

Required fields

04 spatial.json

The heart of the format: every track, its movements over time, and the listening environment.

{
  "tracks": [
    { "id":"track_01", "filename":"tracks/track_01.opus",
      "type":"spatial_object", "spatial_enabled":true,
      "rendering_algorithm":"HRTF",
      "initial_position":{"x":0,"y":0,"z":1} }
  ],
  "movements": [
    { "track_id":"track_01",
      "keyframes":[
        { "time":0,  "position":{"x":-1,"y":0,"z":1}, "volume":0.8 },
        { "time":20, "position":{"x":1, "y":0,"z":-1} }
      ] }
  ],
  "playback": { "fade_in":2.0, "loop_enabled":true }
}

05 Track types

Two kinds of track: a non-spatial stereo bed, and freely positionable 3D objects.

Rendering algorithms

Note: spatial objects must be mono — only mono inputs can be placed in 3D. The stereo bed keeps its full image and never passes through the spatial renderer.

06 Coordinate system

The listener sits at the origin, facing +Z.

07 Keyframe parameters

Each movement is a list of keyframes, interpolated at 60 fps. Only time and position are required; everything else inherits the previous value.

08 Environment

Global reverb and distance attenuation shape the perceived space.

Reverb presets

none · smallRoom · mediumRoom · largeRoom · mediumHall · largeHall · cathedral · plate · chamber

Distance attenuation models

09 Playback

Load, then render — with a clean fallback path for devices without spatial audio.

Load

• Download the .smx file and unpack the ZIP.
• Parse manifest.json → verify codec and track count.
• Parse spatial.json → load tracks and movements.
• Position tracks at their initial coordinates and start playback.
• Interpolate keyframes at 60 fps; update position and volume in real time.

Fallback logic

if device.supportsSpatialAudio {
  play(objects)            // spatial objects through HRTF
} else if binaural_fallback {
  play(bed_left, bed_right) // stereo bed
} else {
  downmixToStereo(objects)  // last resort
}

10 File sizes

Five minutes, five object tracks — SAIMOX stays small because it leans on open, efficient codecs.

11 Roadmap

saimox 1.0 is deliberately offline-first — download, unpack, play. Streaming is planned, and object-based audio has a real structural advantage here: discrete objects can be prioritised and loaded independently, which a bed-plus-offset stream cannot do.

12 License

The SAIMOX format is fully open and license-free.

• No patents.
• No royalties.
• No restrictions on commercial use.
• Built on open codecs — Opus is BSD-licensed.

Real 3D audio. No Dolby. No license. No bullshit.