feat: camera_server v2 — encodeur hw v4l2h264enc + fallback sw

- Suppression du bloc MJPEG (double pipeline impossible sur Pi Zero 2W,
  interdit par CLAUDE.md : Flask = health + settings uniquement)
- Encodeur par défaut : v4l2h264enc hardware (/dev/video11, bcm2835-codec)
  attend ~40% CPU vs 80-90% avec x264enc
- Fallback automatique vers x264enc si v4l2h264enc échoue au démarrage
- Correction pipeline split : shlex.split() remplace .split() (bug caps GStreamer)
- Lecture stderr gst-launch en temps réel (thread daemon)
- GstManager : restart propre via SIGTERM sur le process GStreamer
- Signal SIGTERM/SIGINT : arrêt propre du process GStreamer
- /settings POST : changement à chaud de jetson_host, bitrate, encoder, etc.
- CLAUDE.md : correction "pas de GPU" → VideoCore IV + pipelines hw/sw documentés

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-06-09 10:52:14 +02:00
parent 9221a1a2b9
commit e2ceeded8a
2 changed files with 226 additions and 149 deletions

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# WireClaw — Pi Zero 2W
## Contexte
Composant vidéo du drone d'inspection WireClaw.
Caméra OV5647 (CSI) → GStreamer RTP H264 → Jetson
## Hardware
- Modèle : Raspberry Pi Zero 2W
- CPU : 4× ARM Cortex-A53 @1GHz
- GPU : VideoCore IV — encodeur H264 hardware disponible via v4l2h264enc (/dev/video11)
- RAM : 512MB
- OS : Raspberry Pi OS Bookworm Lite (64-bit)
- Caméra : OV5647 (module CSI standard Raspberry Pi)
- Boîtier : dissipateur thermique
- Charge CPU encodage : ~40% CPU (hw) vs ~80-90% (sw x264)
- Prérequis : gpu_mem=160 dans /boot/firmware/config.txt
## Stack
- OS : Raspberry Pi OS Bookworm Lite
- Caméra : OV5647, libcamerasrc (pas v4l2src)
- Encodage : x264enc tune=zerolatency bitrate=1000
- Transport : RTP H264 pt=96 UDP port 5600
- Caméra : libcamerasrc OBLIGATOIRE (Bookworm, pas v4l2src)
- Encodage : v4l2h264enc hardware (défaut) → x264enc software (fallback auto)
- omxh264enc : non disponible sur Bookworm 64-bit (OpenMAX supprimé)
- Transport : RTP H264 pt=96 UDP
- Flask : API légère port 5000 (health + settings uniquement, pas de MJPEG local)
## Réseau
- Dev Freebox : Pi Zero 192.168.1.132 → Jetson 192.168.1.84
- Hotspot WireClaw : Pi Zero DHCP → Jetson 10.42.0.1
- Dev Freebox : 192.168.1.132 → Jetson 192.168.1.84:5600
- Hotspot WireClaw : DHCP → Jetson 10.42.0.1:5600
## Pipeline émetteur validé
## Pipelines validés
### Hardware (v4l2h264enc) — défaut
gst-launch-1.0 libcamerasrc ! \
video/x-raw,width=640,height=480,format=NV12,framerate=15/1 ! \
v4l2convert ! \
v4l2h264enc video-bitrate=1000000 extra-controls="controls,repeat_sequence_header=1" ! \
video/x-h264,level=(string)3.2 ! \
h264parse ! \
rtph264pay config-interval=1 pt=96 ! \
udpsink host=192.168.1.84 port=5600
### Software (x264enc) — fallback
gst-launch-1.0 libcamerasrc ! \
video/x-raw,width=640,height=480,framerate=15/1 ! \
videoconvert ! x264enc tune=zerolatency bitrate=1000 ! \
rtph264pay config-interval=1 pt=96 ! \
udpsink host=192.168.1.84 port=5600
## Rôle dans WireClaw
- Émet uniquement le flux RTP vers le Jetson
- Pas de traitement local (YOLOv8 tourne sur le Jetson CUDA)
- Réglages caméra via POST /settings (proxyfié depuis FastAPI Jetson)
## Repo
git.syoul.fr/nicoboy/wireclaw-pizero

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#!/usr/bin/env python3
"""
WireClaw — Pi Zero 2W camera server
- MJPEG local stream on port 5000 (Flask)
- RTP H264 stream to Jetson 192.168.1.84:5600 (GStreamer thread)
Flask API port 5000 : /health /settings
RTP H264 → Jetson via GStreamer subprocess
Encoder strategy: v4l2h264enc hardware (default) → x264enc software (auto-fallback)
"""
import os
import shlex
import signal
import subprocess
import threading
import time
import logging
import cv2
from flask import Flask, Response
from flask import Flask, jsonify, request
# --- Configuration -----------------------------------------------------------
JETSON_HOST = "192.168.1.84"
JETSON_PORT = 5600
DEFAULTS: dict = {
"jetson_host": "192.168.1.84",
"jetson_port": 5600,
"width": 640,
"height": 480,
"fps": 15,
"bitrate_kbps": 1000,
# "auto" tries hw then sw; "hw" forces v4l2h264enc; "sw" forces x264enc
"encoder": "auto",
}
MJPEG_PORT = 5000
MJPEG_WIDTH = 640
MJPEG_HEIGHT = 480
MJPEG_FPS = 15
MJPEG_QUALITY = 80 # JPEG quality (0-100)
GST_PIPELINE = (
"libcamerasrc ! "
"video/x-raw,width=640,height=480,framerate=15/1 ! "
"videoconvert ! "
"x264enc tune=zerolatency bitrate=1000 ! "
"rtph264pay config-interval=1 pt=96 ! "
f"udpsink host={JETSON_HOST} port={JETSON_PORT}"
)
# OpenCV capture pipeline for MJPEG (reads raw frames from libcamera)
CV_PIPELINE = (
"libcamerasrc ! "
"video/x-raw,width=640,height=480,framerate=15/1 ! "
"videoconvert ! "
"video/x-raw,format=BGR ! "
"appsink drop=true max-buffers=2"
)
FLASK_PORT = 5000
# --- Logging -----------------------------------------------------------------
@ -50,134 +40,196 @@ logging.basicConfig(
)
log = logging.getLogger(__name__)
# --- GStreamer RTP thread -----------------------------------------------------
# --- Pipeline builder --------------------------------------------------------
_gst_proc: subprocess.Popen | None = None
_gst_lock = threading.Lock()
def _build_pipeline(cfg: dict, encoder: str) -> str:
w, h, fps = cfg["width"], cfg["height"], cfg["fps"]
host, port = cfg["jetson_host"], cfg["jetson_port"]
sink = f"rtph264pay config-interval=1 pt=96 ! udpsink host={host} port={port}"
def _gst_worker() -> None:
"""Run GStreamer RTP emitter; restart on failure."""
global _gst_proc
cmd = ["gst-launch-1.0", "-e"] + GST_PIPELINE.split()
while True:
log.info("GStreamer RTP: starting → %s:%s", JETSON_HOST, JETSON_PORT)
try:
proc = subprocess.Popen(
cmd,
stdout=subprocess.DEVNULL,
stderr=subprocess.PIPE,
)
with _gst_lock:
_gst_proc = proc
_, stderr = proc.communicate()
rc = proc.returncode
if stderr:
log.warning("GStreamer stderr: %s", stderr.decode(errors="replace").strip())
log.warning("GStreamer exited with code %d — restarting in 3 s", rc)
except Exception as exc:
log.error("GStreamer launch failed: %s", exc)
time.sleep(3)
def start_rtp_thread() -> threading.Thread:
t = threading.Thread(target=_gst_worker, name="gst-rtp", daemon=True)
t.start()
return t
# --- MJPEG capture & streaming -----------------------------------------------
_cap: cv2.VideoCapture | None = None
_frame_lock = threading.Lock()
_latest_frame: bytes | None = None
def _capture_worker() -> None:
"""Continuously grab frames from libcamera via GStreamer appsink."""
global _cap, _latest_frame
log.info("MJPEG capture: opening libcamerasrc pipeline")
cap = cv2.VideoCapture(CV_PIPELINE, cv2.CAP_GSTREAMER)
if not cap.isOpened():
log.error("Failed to open capture pipeline — MJPEG unavailable")
return
_cap = cap
log.info("MJPEG capture: pipeline open")
while True:
ok, frame = cap.read()
if not ok:
log.warning("MJPEG capture: frame grab failed, retrying…")
time.sleep(0.1)
continue
_, jpg = cv2.imencode(
".jpg", frame, [cv2.IMWRITE_JPEG_QUALITY, MJPEG_QUALITY]
if encoder == "hw":
bitrate_bps = cfg["bitrate_kbps"] * 1000
# NV12 format avoids a CPU color-conversion step before v4l2convert
# level=(string)3.2 is required — default level 1.0 caps at 176x144
return (
f"libcamerasrc ! "
f"video/x-raw,width={w},height={h},format=NV12,framerate={fps}/1 ! "
f"v4l2convert ! "
f"v4l2h264enc video-bitrate={bitrate_bps} "
f'extra-controls="controls,repeat_sequence_header=1" ! '
f"video/x-h264,level=(string)3.2 ! "
f"h264parse ! "
f"{sink}"
)
with _frame_lock:
_latest_frame = jpg.tobytes()
# sw
return (
f"libcamerasrc ! "
f"video/x-raw,width={w},height={h},framerate={fps}/1 ! "
f"videoconvert ! "
f"x264enc tune=zerolatency bitrate={cfg['bitrate_kbps']} ! "
f"{sink}"
)
# --- GStreamer process manager -----------------------------------------------
class GstManager:
def __init__(self) -> None:
self._cfg: dict = dict(DEFAULTS)
self._lock = threading.Lock()
self._proc: subprocess.Popen | None = None
self._restart_event = threading.Event()
self._shutdown = threading.Event()
self._thread: threading.Thread | None = None
self.encoder_active: str | None = None
# Public API
def start(self) -> None:
self._thread = threading.Thread(target=self._worker, name="gst-rtp", daemon=True)
self._thread.start()
def stop(self) -> None:
self._shutdown.set()
self._terminate()
def restart_with(self, patch: dict) -> None:
with self._lock:
self._cfg.update(patch)
self._terminate()
def is_alive(self) -> bool:
with self._lock:
return self._proc is not None and self._proc.poll() is None
def get_cfg(self) -> dict:
with self._lock:
return dict(self._cfg)
# Internal
def _terminate(self) -> None:
with self._lock:
proc = self._proc
if proc and proc.poll() is None:
proc.terminate()
try:
proc.wait(timeout=3)
except subprocess.TimeoutExpired:
proc.kill()
def _launch(self, encoder: str) -> "subprocess.Popen | None":
with self._lock:
cfg = dict(self._cfg)
pipeline = _build_pipeline(cfg, encoder)
cmd = ["gst-launch-1.0", "-e"] + shlex.split(pipeline)
log.info("GStreamer [%s] pipeline: %s", encoder, pipeline)
try:
return subprocess.Popen(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.PIPE, text=True)
except FileNotFoundError:
log.error("gst-launch-1.0 not found in PATH")
return None
@staticmethod
def _drain_stderr(proc: "subprocess.Popen") -> None:
for line in proc.stderr:
stripped = line.rstrip()
if stripped:
log.debug("gst: %s", stripped)
def _worker(self) -> None:
with self._lock:
pref = self._cfg.get("encoder", "auto")
if pref == "hw":
queue = ["hw"]
elif pref == "sw":
queue = ["sw"]
else:
queue = ["hw", "sw"]
while not self._shutdown.is_set():
for enc in queue:
proc = self._launch(enc)
if proc is None:
continue
with self._lock:
self._proc = proc
self.encoder_active = enc
log.info("RTP stream running (encoder=%s)", enc)
stderr_t = threading.Thread(target=self._drain_stderr, args=(proc,), daemon=True)
stderr_t.start()
proc.wait()
rc = proc.returncode
if self._shutdown.is_set():
return
log.warning("GStreamer [%s] exited rc=%d", enc, rc)
if enc == "hw" and pref == "auto":
log.warning("Hardware encoder failed — permanent fallback to x264enc")
queue = ["sw"]
break # restart outer while-loop with updated queue
if not self._shutdown.is_set():
log.info("Restarting in 3 s…")
time.sleep(3)
def start_capture_thread() -> threading.Thread:
t = threading.Thread(target=_capture_worker, name="mjpeg-cap", daemon=True)
t.start()
return t
def _mjpeg_generator():
boundary = b"--frame\r\nContent-Type: image/jpeg\r\n\r\n"
while True:
with _frame_lock:
frame = _latest_frame
if frame is None:
time.sleep(0.05)
continue
yield boundary + frame + b"\r\n"
time.sleep(1.0 / MJPEG_FPS)
_gst = GstManager()
# --- Flask app ---------------------------------------------------------------
app = Flask(__name__)
@app.route("/")
def index():
return (
"<html><body>"
"<h2>WireClaw Pi Zero — camera feed</h2>"
'<img src="/stream" />'
"</body></html>"
)
@app.route("/stream")
def stream():
return Response(
_mjpeg_generator(),
mimetype="multipart/x-mixed-replace; boundary=frame",
)
@app.route("/health")
def health():
with _frame_lock:
has_frame = _latest_frame is not None
with _gst_lock:
gst_alive = _gst_proc is not None and _gst_proc.poll() is None
status = "ok" if (has_frame and gst_alive) else "degraded"
return {"status": status, "mjpeg": has_frame, "rtp": gst_alive}
alive = _gst.is_alive()
return jsonify({
"status": "ok" if alive else "degraded",
"rtp": alive,
"encoder": _gst.encoder_active,
})
@app.route("/settings", methods=["GET"])
def settings_get():
return jsonify(_gst.get_cfg())
@app.route("/settings", methods=["POST"])
def settings_post():
data = request.get_json(force=True, silent=True) or {}
allowed = {"jetson_host", "jetson_port", "width", "height", "fps", "bitrate_kbps", "encoder"}
patch = {k: v for k, v in data.items() if k in allowed}
if not patch:
return jsonify({"error": "no valid fields", "allowed": sorted(allowed)}), 400
_gst.restart_with(patch)
return jsonify({"status": "restarting", "applied": patch})
# --- Shutdown ----------------------------------------------------------------
def _on_signal(sig, _frame) -> None:
log.info("Signal %d — shutting down", sig)
_gst.stop()
os._exit(0)
# --- Entrypoint --------------------------------------------------------------
if __name__ == "__main__":
start_rtp_thread()
start_capture_thread()
signal.signal(signal.SIGTERM, _on_signal)
signal.signal(signal.SIGINT, _on_signal)
# Give the pipelines a moment to initialise before accepting connections
time.sleep(2)
_gst.start()
time.sleep(1)
log.info("Flask MJPEG server starting on port %d", MJPEG_PORT)
app.run(host="0.0.0.0", port=MJPEG_PORT, threaded=True)
log.info("Flask API on 0.0.0.0:%d", FLASK_PORT)
app.run(host="0.0.0.0", port=FLASK_PORT, threaded=True)