AngePierreandClaude Opus 5
c167c836e6
Extract the install that was applied by hand to the Jetson Nano into a single checkout that builds itself for whatever Jetson it lands on. The two nodes on the rig share no JetPack — tegra210 caps at 4, tegra234 needs 5+ — so nothing binary is portable between them. The source and the procedure are: install.sh detects the platform (L4T / JetPack / SoC), installs deps, builds the OrbbecSDK and the preview server from source locally, and generates a per-user config and systemd unit. The tested bridge.py ships verbatim; all machine-specific paths live in the generated config, so it stays unmodified — its one hardcoded path is made home-relative. The retired GStreamer/RTSP target is dropped: the direct route encodes no video. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
105 lines
4.2 KiB
Markdown
105 lines
4.2 KiB
Markdown
# Ithaca capture node
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The software a Jetson runs to join an Ithaca RGBD capture rig: a Python bridge that
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puts the node on the WebSocket mesh and answers Preview / Record, and a C++ preview
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server that streams each camera's colour (the sensor's own JPEG) and depth (its own
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16-bit millimetres, LZ4-compressed) straight to the Unity viewer.
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One checkout, one command, on any Jetson:
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```sh
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git clone <this repo> ~/ithaca-node
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cd ~/ithaca-node
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./install.sh
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```
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## Why an install script and not a disk image
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The rig currently spans two Jetsons with **no JetPack in common**:
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| Node | SoC | JetPack | Ubuntu / CUDA |
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|------|-----|---------|---------------|
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| Jetson Nano (2019) | tegra210 | **4.x only** (EOL) | 18.04 / 10.2 |
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| Jetson Orin Nano | tegra234 | **5 or 6** | 22.04 / 12.x |
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tegra210 never got a newer L4T and the Orin refuses the old one, so no single OS
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image covers both, and no compiled binary is portable between them — CUDA, glibc
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and the C++ ABI all differ by generation.
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What *is* portable is the **source and the procedure**. `install.sh` detects the
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platform and builds the C++ locally against a locally-built OrbbecSDK, so the same
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command produces a correct binary on each machine. Adding a future Orin NX or a Thor
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needs nothing new here — the script compiles against whatever toolchain it finds.
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The bridge is pure Python and already runs identically everywhere; keep it that way
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by never giving it a dependency that has to be compiled.
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## Layout
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```
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install.sh one entry point, idempotent
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bridge/
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bridge.py the node client — shipped verbatim, tested in place
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config.template.json @PLACEHOLDERS@ filled per user by install.sh
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server/
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ithaca_rgbd_server.cpp the preview server
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CMakeLists.txt links a prebuilt libOrbbecSDK, no GStreamer
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systemd/
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ithaca-bridge.service.in templated with the user and repo path
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usbfs-memory.service raises usbfs_memory_mb for the camera bandwidth
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udev/
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99-obsensor-libusb.rules reference copy (the SDK's own installer wins if present)
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scripts/
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detect_platform.sh L4T / JetPack / SoC, as KEY=value
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install_deps.sh apt + websockets
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build_sdk.sh reuse or build OrbbecSDK v2 for this platform
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build_server.sh cmake + make the preview server
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```
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## What install.sh does
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1. Detects L4T / JetPack / SoC (`scripts/detect_platform.sh`).
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2. Installs build and run dependencies (no GStreamer — the direct route encodes no
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video).
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3. Locates a working OrbbecSDK build, or clones and builds one. A node that already
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has a good build (the Nano) is left untouched.
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4. Builds `ithaca_rgbd_server` against it.
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5. Generates `bridge/config.json` for the current user — this is where all the
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machine-specific paths live, so `bridge.py` itself stays unmodified.
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6. Installs the udev rules and the `usbfs-memory` service, and adds the user to the
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`video` group.
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7. Generates and starts the `ithaca-bridge` systemd service.
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Re-run it after a `git pull`: it rebuilds, regenerates the unit and config, and
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restarts the service. It keeps an existing `config.json` (delete it to regenerate)
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and an existing SDK build.
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## The SDK is the one thing to watch on a new JetPack
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`build_sdk.sh` reuses an existing build when it finds one. On a machine with none it
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clones the official OrbbecSDK v2 and builds it — this is the step most likely to
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need attention on a JetPack it has not been tried on. If it fails, build the SDK by
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hand once and re-run with its location:
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```sh
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OB_SDK_ROOT=/path/to/OrbbecSDK_v2 ./install.sh
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```
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Override the source with `OB_SDK_REPO` / `OB_SDK_REF` to pin a tag known to build on
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your JetPack.
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## Operating the node
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```sh
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systemctl status ithaca-bridge # is it up
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journalctl -u ithaca-bridge -f # live log
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```
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Runtime state the bridge writes beside itself (git-ignored):
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- `config.json` — this machine's config (generated).
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- `cam_settings.json` — per-camera settings, kept across restarts.
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- `stream_map.txt` — the live composition: line 1 the cameras to stream, line 2 the
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alignment (`raw` or `compare`). The preview server re-reads it once a second, so a
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camera can be turned on or off, and Compare switched, without restarting.
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