ogg-playlist-sctp

Streams Opus pages from multi or single track Ogg containers, exposes the playlist over an SCTP DataChannel, and lets the browser hop between tracks while showing artist/title metadata parsed from OpusTags.

What this showcases

Reads multi-stream Ogg containers with oggreader and keeps per-serial playback state.
Publishes playlist + now-playing metadata (artist/title/vendor/comments) over a DataChannel.
Browser can send next, prev, or a 1-based track number to jump around.
Audio is sent as an Opus TrackLocalStaticSample over RTP, metadata/control ride over SCTP.

Prepare a demo playlist

The example looks for playlist.ogg in the working directory. You can provide your own playlist.ogg or generate it by running one of the following ffmpeg commands:

Fake two-track Ogg with metadata (artist/title per stream)

ffmpeg \
  -f lavfi -t 8 -i "sine=frequency=330" \
  -f lavfi -t 8 -i "sine=frequency=660" \
  -map 0:a -map 1:a \
  -c:a libopus -page_duration 20000 \
  -metadata:s:a:0 artist="Pion Artist" -metadata:s:a:0 title="Fake Intro" \
  -metadata:s:a:1 artist="Open-Source Friend" -metadata:s:a:1 title="Fake Outro" \
  playlist.ogg

Single-track fallback with tags

ffmpeg -f lavfi -t 10 -i "sine=frequency=480" \
  -c:a libopus -page_duration 20000 \
  -metadata artist="Solo Bot" -metadata title="One Track Demo" \
  playlist.ogg

Run it

Build the binary:

go install github.com/pion/webrtc/v4/examples/play-from-disk-playlist-control@latest

Run it from the directory containing playlist.ogg (override port with -addr if you like):
```
play-from-disk-playlist-control
# or
play-from-disk-playlist-control -addr :8080
```
Open the hosted UI in your browser and press Start Session:
```
http://localhost:8080
```
Signaling is WHEP-style: the browser POSTs plain SDP to /whep and the server responds with the answer SDP. Use the buttons or type next / prev / a track number to switch tracks. Playlist metadata and now-playing updates arrive over the DataChannel; Opus audio flows on the media track.