Files
netris-nestri/apps/neswire/README.md
Wanjohi 6ea241c910 docs: the guest READMEs described code that is gone
All three came across with their standalone repos and none had been
touched since the transport changed.

nescapture claimed to packetize with Reed-Solomon FEC and stream RTP/UDP
to a Moonlight client. It sends encoded frames to neshub over a Unix
socket. packetizer.rs, control.rs and shard_batch.rs do not exist, and
neither does ARCHITECTURE.md. Nine documented environment variables are
not read by anything -- NESCAPTURE_RTP_HOST was listed as *required* --
and five that are read were undocumented, including the one that says
where frames go. Someone following that quick start would have set a
required variable that does nothing and got no output.

Documented the three sockets, since nescapture binds one and connects to
two and that was written down nowhere.

neswire documented --rtp-addr and --channels against a gstreamer pipeline.
It has --ipc-path, --channels, --packet-duration-ms and
--bitrate-per-channel, and hub-stub exists precisely so it can be tested
without a hub. Kept the reason hub-stub decodes rather than counts bytes:
Opus codes silence at ~3 kbps, so a dead sink looks alive on a meter.

nescope was mostly right. It called the capture layer "vkcapture", listed
seven of fifteen modules and five of nine flags, and its TODO list was
three items that neshub and nescapture now do. Added compositor mode,
which is the shape a real session uses and was undocumented.

All three licence lines were "TBD" or "See project repository".
2026-08-26 19:09:53 +03:00

82 lines
2.3 KiB
Markdown

# neswire
A PipeWire sink that Opus-encodes guest audio and sends it to
[`neshub`](../neshub).
Audio in the guest has no speakers to reach, so neswire registers itself as an
output device and takes what anything plays into it. From the application's
side it is an ordinary sink.
---
## Running it
```bash
cargo run --release --bin neswire
```
Then select the **neswire** sink as the system output, or point an application
at it.
| Flag | Env | Default | Description |
| --- | --- | --- | --- |
| `--ipc-path` | `NESWIRE_IPC_PATH` | `/tmp/nestri-audio.sock` | Where to send Opus packets |
| `--channels` | `NESWIRE_CHANNELS` | `2` | `2` stereo, `6` for 5.1, `8` for 7.1 |
| `--packet-duration-ms` | `NESWIRE_PACKET_DURATION_MS` | `5` | Opus frame size in ms |
| `--bitrate-per-channel` | `NESWIRE_BITRATE_PER_CHANNEL` | `64` | kbps per channel |
`RUST_LOG` takes a standard tracing filter, e.g. `RUST_LOG=neswire=debug`.
Sample rate is fixed at 48 kHz, which is what Opus wants and what every
consumer device runs at anyway.
---
## Testing without a hub
neswire's only output is a Unix datagram socket that `neshub` binds, so running
it on a desktop means it has nothing to talk to — it retries `connect` forever
and there is no way to see what it would have sent. `hub-stub` binds that
socket and reports what arrives:
```bash
# terminal 1
cargo run --bin hub-stub
# terminal 2
cargo run --bin neswire
```
It **decodes** the Opus rather than counting bytes, and that distinction
matters more than it looks. Opus codes digital silence in about two bytes a
packet, so a sink that is receiving nothing but zeros still produces a steady
~3 kbps and looks correct on every meter downstream. Peak amplitude is what
tells a working sink from a silent one.
```bash
cargo run --bin hub-stub -- --channels 8 # match neswire's channel count
```
`hub-stub` mirrors `ipc_listener::run_audio_listener` in `neshub`: same bind,
same `0o666`, same stream-type and codec checks. Where the two disagree,
`neshub` is right and the stub should be corrected.
---
## Layout
```
src/
├── main.rs CLI, wiring, the sink→encoder→IPC chain
├── sink.rs the PipeWire sink itself
├── encoder.rs Opus encode, including the multichannel mappings
└── bin/
└── hub-stub.rs
```
---
## Licence
Apache 2.0. See [LICENSE](../../LICENSE).