feat: point the fleet at wss LiveKit room uwh-telhai

Publish and subscribe over wss://livekit.uni-wh.de:7800 and refuse
cleartext ws://. Conference room is uwh-telhai. Includes the uncommitted
encoded H.264 publish path, Rally hairpin, and KMS wall overlay.

i420_nv12.py

@@ -0,0 +1,76 @@
+"""16-align I420→NV12 for Intel VA (NV12 only). Pad up, never crop."""
+from __future__ import annotations
+
+import numpy as np
+
+
+def coded_dim(n: int) -> int:
+    n = int(n)
+    if n <= 0:
+        return 0
+    return (n + 15) // 16 * 16
+
+
+def nv12_bytes(width: int, height: int) -> int:
+    return int(width) * int(height) * 3 // 2
+
+
+def va_visible_height(width: int, height: int) -> int:
+    """Drop the 8-row VA pad when the remainder is 16:9 (360/1080)."""
+    w, h = int(width), int(height)
+    vis = h - 8
+    if w > 0 and vis > 0 and vis * 16 == w * 9:
+        return vis
+    return h
+
+
+def drop_va_pad_i420(src, width: int, height: int):
+    """Crop coded pad off I420. Returns (payload, w, visible_h)."""
+    w, h = int(width), int(height)
+    vis = va_visible_height(w, h)
+    if vis == h:
+        return src, w, h
+    ysz = w * h
+    uvw, uvh = w // 2, h // 2
+    uvsz = uvw * uvh
+    raw = np.frombuffer(src, dtype=np.uint8, count=ysz + 2 * uvsz)
+    y = raw[:ysz].reshape(h, w)[:vis, :]
+    u = raw[ysz:ysz + uvsz].reshape(uvh, uvw)[: vis // 2, :]
+    v = raw[ysz + uvsz:ysz + 2 * uvsz].reshape(uvh, uvw)[: vis // 2, :]
+    out = np.empty(w * vis * 3 // 2, dtype=np.uint8)
+    out[: w * vis] = y.reshape(-1)
+    out[w * vis:w * vis + (w // 2) * (vis // 2)] = u.reshape(-1)
+    out[w * vis + (w // 2) * (vis // 2):] = v.reshape(-1)
+    return out.tobytes(), w, vis
+
+
+def i420_to_nv12_into(src, width: int, height: int, out: bytearray) -> int:
+    """Pad to 16-aligned WxH and write NV12 into out. Returns nbytes."""
+    w, h = int(width), int(height)
+    cw, ch = coded_dim(w), coded_dim(h)
+    need = nv12_bytes(cw, ch)
+    if len(out) < need:
+        raise ValueError("NV12 dest too small")
+    ysz = w * h
+    uvw, uvh = w // 2, h // 2
+    uvsz = uvw * uvh
+    raw = np.frombuffer(src, dtype=np.uint8, count=ysz + 2 * uvsz)
+    y = raw[:ysz].reshape(h, w)
+    u = raw[ysz:ysz + uvsz].reshape(uvh, uvw)
+    v = raw[ysz + uvsz:ysz + 2 * uvsz].reshape(uvh, uvw)
+    nv = np.frombuffer(out, dtype=np.uint8, count=need).reshape(ch + ch // 2, cw)
+    nv[:h, :w] = y
+    if ch > h:
+        nv[h:ch, :w] = y[-1]
+    if cw > w:
+        nv[:ch, w:cw] = nv[:ch, w - 1:w]
+    uv = nv[ch:, :].reshape(ch // 2, cw // 2, 2)
+    uh, uw = h // 2, w // 2
+    uv[:uh, :uw, 0] = u
+    uv[:uh, :uw, 1] = v
+    if ch // 2 > uh:
+        uv[uh:, :uw, 0] = u[-1]
+        uv[uh:, :uw, 1] = v[-1]
+    if cw // 2 > uw:
+        uv[:, uw:, :] = uv[:, uw - 1:uw, :]
+    return need