Multicast karaoke that dares to leave the house — CD+G over UDP, real codecs, late join, and enough Windows zips to fill a USB stick of doom (lovingly).

Fork: andrew867/dashcdg · upstream history: AppleDash/dashcdg.

This line of work was never about stopping to ask why—it was about finding out whether it was possible: MP3+G-style transport with repair, multiple desktop front-ends (OpenGL, Win32 GDI, headless), and packaging that still runs on the weird old laptop in the back of the closet. If you want enterprise polish and a 24/7 NOC, buy a box; if you want to see the packets fly, you are probably in the right place.

• Attitude, on purpose: docs/fork-manifesto.md
• Contribute / build / tests: docs/CONTRIBUTING.md
• Long-form doc index: docs/README.md
• Latest release notes: docs/releases/v0.4.0.md
• Receiver + debugging handoff: AGENTS.md
• Author / other public work (short): docs/ops/portfolio.md

dashcdg is a karaoke transport and desktop reference implementation:

• Deterministic CD+G decode, replay, and seek
• A versioned UDP protocol (v4 on the wire by default; --v3 for legacy)
• Desktop TX/RX for IPv4 multicast and broadcast
• Live audio over the wire: Opus, AMR wide/narrow, EVRC, QCELP, NB-IMA, SBC-style low-rate modes — plus timed CD+G batches, snapshots, and bounded FEC so bursty Wi-Fi does not end the party

The transmitter pushes audio and graphics on parallel timelines; the receiver can cold-join, repair losses, and re-anchor from v4 snapshots without downloading a full .cdg file over the air first.

Windows builds are first-class: headless desktop-tx, GL desktop-rx with GDI fallback, dedicated desktop-gdi-rx.exe / desktop-gdi-tx.exe, and a retro bundle without OpenGL (still Opus + PortAudio, with PIII-friendly DLLs on i386). The full matrix, exe names, and zip layouts live in docs/specs/desktop-platform-support.md.

git clone <this-repo>
cd dashcdg
make
make test

On MSYS2 / MinGW you also need vendored libsoxr before linking the full desktop stack:

make vendor-soxr
make desktop-apps

Run a build output from build/amd64/bin/ or build/x86/bin/ (paths vary by arch — see the platform spec above). The repo includes a large optional cdg/ sample library; see docs/test/sample-media.md.

Network defaults: multicast 239.255.77.77, UDP 24684; point TX and RX at the same group/port and press play.

Deeper: docs/specs/transport-protocol.md, docs/specs/bad-network-transport.md, docs/architecture/desktop-streaming.md.

TX audio isolation (2026): the send path can release audio without getting stuck behind PTP or RX stats work — see docs/architecture/tx-audio-isolation.md. Lip-sync on RX uses a realistic host output latency on PortAudio/WASAPI; see docs/specs/v4-display-audio-sync.md.

POSIX / generic: make, make debug, make test.

Windows: vendor soxr (see docs/specs/pcm-libsoxr-desktop-src.md), and for i686 sneakernet also vendor Opus/PortAudio sources (make vendor-audio-sources or docs/specs/windows-legacy-mingw-build.md).

Portable zips:

scripts/build_release.sh x64    # or x86, all
# or: make dist-windows

Sneakernet USB tree (x64 + x86 + legacy P3 + retro):

make dist-windows-sneakernet
# → build/dist/dashcdg-windows-sneakernet/ + .zip; README inside the folder

Toggles: see header of scripts/build_windows_sneakernet_dist.sh. Desktop apps print a git-stamped build id at startup so soak logs point at the right commit.

On tags matching v*, .github/workflows/release-sneakernet.yml attaches dashcdg-windows-sneakernet.zip and a sample track zip from cdg/. Manual workflow_dispatch runs can target a release_tag too.

Dependencies (high level): OpenGL + GLEW + FreeGLUT for GL builds; GDI path avoids GL; PortAudio + Opus everywhere for desktop; AVRT / winmm for timing (see platform/desktop/src/win32_timing_boost.c).

UI: Arrow keys seek in the player; TX uses space/pause, next/prev, quit, etc. — --help on the binary wins over this README when they disagree.

flowchart LR
  src[CDG + MP3 library] --> txprep[TX track load + queues]
  txprep --> ann[ANNOUNCE / CLOCK / v4 session]
  txprep --> ach[AUDIO path]
  txprep --> cb[CDG batches + snapshots]
  ach --> fec[FEC / repair]
  cb --> fec
  ann --> rxstate[RX session]
  ach --> rxjit[Jitter + repair]
  cb --> rxjit
  rxjit --> rxaud[Decode → PortAudio]
  rxjit --> rxcdg[Live CD+G]
  rxaud --> render[GL or GDI + HUD]
  rxcdg --> render

Impaired-network relay: docs/test/desktop-impairment-validation.md and scripts/desktop_impairment.py.

Track the wish list: docs/specs/remaining-tranches-roadmap.md.

MIT — see LICENSE (root). AppleDash is credited in the file header; this fork’s changes follow the same license.

• docs/ops/quality-gates.md
• docs/test/desktop-proof-plan.md
• docs/specs/receiver-progress-invariants.md
• docs/architecture/threaded-streaming-runtime.md

You made it to the end. Go break something, run make test, and if the lyrics and the snare line up, that counts as a good afternoon.