feat(nvenc): GPU sidecar passthrough + All-Intra HEVC capture codec

Phase 0.2 of the NVENC All-Intra HEVC ingest plan.

node-agent/handleSidecarStart:
- Accept useGpu: true in the sidecar start body
- When useGpu: adds Runtime=nvidia, DeviceRequests=[gpu], and injects
  NVIDIA_VISIBLE_DEVICES=all + NVIDIA_DRIVER_CAPABILITIES=video,compute,utility
  into the container env. CPU-codec recorders are unaffected (useGpu defaults false).

mam-api/recorders (start endpoint):
- Derive useGpu from recorder.recording_codec — true for hevc_nvenc/h264_nvenc
- Pass useGpu to remote sidecar start body
- Apply same Runtime/DeviceRequests to the local Docker spawn path

capture/capture-manager:
- Update hevc_nvenc codec entry with all-intra flags:
  -g 1 -bf 0 (every frame IDR, no B-frames — required for growing-file
  edit-while-record), -rc vbr, -profile:v main10, pixFmt p010le (10-bit 4:2:0)

Next: validation gate (§8) — test MXF OP1a then fragmented MOV on one
DeckLink channel, mount in Premiere while recording.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

services/capture/src/capture-manager.js

@@ -28,7 +28,19 @@ const VIDEO_CODECS = {
   h264:         { args: ['-c:v', 'libx264', '-preset', 'medium'],   bitrateControl: true,  pixFmt: 'yuv420p' },
   h264_nvenc:   { args: ['-c:v', 'h264_nvenc', '-preset', 'p5'],    bitrateControl: true,  pixFmt: 'yuv420p' },
   h265:         { args: ['-c:v', 'libx265', '-preset', 'medium'],   bitrateControl: true,  pixFmt: 'yuv420p' },
-  hevc_nvenc:   { args: ['-c:v', 'hevc_nvenc', '-preset', 'p5'],    bitrateControl: true,  pixFmt: 'yuv420p' },
+  // All-Intra HEVC on NVENC — the growing-file master codec.
+  // -g 1 -bf 0: every frame is an IDR (all-intra), no B-frames.
+  //   Required for growing-file edit-while-record (partial file must be
+  //   decodable to the last complete frame without a full GOP).
+  // -rc vbr: variable bitrate; pair with a high target bitrate (100–160 Mbps
+  //   for 1080i) to rival ProRes HQ quality.
+  // -profile:v main10 / p010le: 10-bit 4:2:0 — the closest NVENC HEVC can
+  //   get to ProRes 4:2:2 10-bit. If strict 4:2:2 is needed, use prores_hq.
+  hevc_nvenc:   {
+    args: ['-c:v', 'hevc_nvenc', '-preset', 'p4', '-rc', 'vbr', '-g', '1', '-bf', '0', '-profile:v', 'main10'],
+    bitrateControl: true,
+    pixFmt: 'p010le',
+  },
 };
 
 const AUDIO_CODECS = {

services/mam-api/src/routes/recorders.js

@@ -427,6 +427,12 @@ router.post('/:id/start', async (req, res, next) => {
       }
     }
 
+    // GPU-accelerated codecs require the NVIDIA container runtime on the node.
+    // hevc_nvenc / h264_nvenc are the only two we currently support; extend
+    // this list if av1_nvenc or others are added later.
+    const GPU_CODECS = ['hevc_nvenc', 'h264_nvenc'];
+    const useGpu = GPU_CODECS.includes(recorder.recording_codec);
+
     // Determine whether to spawn locally or via a remote node-agent.
     const { remote: isRemote, apiUrl: targetNodeApiUrl } = await resolveNodeTarget(recorder.node_id);
     // For remote sidecars, the capture container runs on the worker host network and cannot
@@ -444,7 +450,7 @@ router.post('/:id/start', async (req, res, next) => {
       const sidecarRes = await fetch(`${targetNodeApiUrl}/sidecar/start`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ image: 'wild-dragon-capture:latest', env, capturePort, sourceType }),
+        body: JSON.stringify({ image: 'wild-dragon-capture:latest', env, capturePort, sourceType, useGpu }),
         signal: AbortSignal.timeout(15000),
       });
       if (!sidecarRes.ok) {
@@ -477,16 +483,28 @@ router.post('/:id/start', async (req, res, next) => {
       }
       if (growingEnabled) hostBinds.push('/mnt/NVME/MAM/wild-dragon-growing:/growing');
 
+      const localEnv = [...env];
+      if (useGpu) {
+        localEnv.push('NVIDIA_VISIBLE_DEVICES=all');
+        localEnv.push('NVIDIA_DRIVER_CAPABILITIES=video,compute,utility');
+      }
+
+      const localHostConfig = {
+        Privileged: true,
+        NetworkMode: dockerNetwork,
+        PortBindings: Object.keys(portBindings).length > 0 ? portBindings : undefined,
+        Binds: hostBinds,
+        ...(useGpu && {
+          Runtime: 'nvidia',
+          DeviceRequests: [{ Driver: 'nvidia', Count: -1, Capabilities: [['gpu']] }],
+        }),
+      };
+
       const containerConfig = {
         Image: 'wild-dragon-capture:latest',
-        Env: env,
+        Env: localEnv,
         ExposedPorts: Object.keys(exposedPorts).length > 0 ? exposedPorts : undefined,
-        HostConfig: {
+        HostConfig: localHostConfig,
-          Privileged: true,
-          NetworkMode: dockerNetwork,
-          PortBindings: Object.keys(portBindings).length > 0 ? portBindings : undefined,
-          Binds: hostBinds,
-        },
         NetworkingConfig: {
           EndpointsConfig: {
             [dockerNetwork]: { Aliases: [alias] },

services/node-agent/index.js

@@ -87,6 +87,12 @@ async function handleSidecarStart(body, res) {
       env = [],
       capturePort = 3001,
       sourceType = 'sdi',
+      // useGpu: true  → attach NVIDIA runtime + NVIDIA_VISIBLE_DEVICES so the
+      // sidecar can call hevc_nvenc / h264_nvenc inside capture ffmpeg.
+      // Only set this when the recorder codec is GPU-accelerated; CPU codecs
+      // (ProRes, DNxHR, libx264) don't need it and it avoids a hard dep on the
+      // NVIDIA container runtime on nodes that have no GPU.
+      useGpu = false,
     } = body;
 
     const binds = [`${LIVE_DIR}:/live`];
@@ -100,14 +106,35 @@ async function handleSidecarStart(body, res) {
       } catch (_) { /* /dev always exists */ }
     }
 
+    // Build the sidecar environment, injecting NVIDIA vars when GPU is requested.
+    const sidecarEnv = [...env, `PORT=${capturePort}`];
+    if (useGpu) {
+      // NVIDIA_VISIBLE_DEVICES=all exposes every GPU on the host.
+      // For a single-GPU node (zampp2 / L4) this is equivalent to pinning GPU 0.
+      // When we later store per-recorder GPU affinity in the DB we can pass a
+      // specific UUID here instead.
+      sidecarEnv.push('NVIDIA_VISIBLE_DEVICES=all');
+      sidecarEnv.push('NVIDIA_DRIVER_CAPABILITIES=video,compute,utility');
+    }
+
+    const hostConfig = {
+      NetworkMode: 'host',
+      Privileged: true,
+      Binds: binds,
+    };
+    if (useGpu) {
+      // Tell Docker to use the NVIDIA container runtime for this container.
+      // Equivalent to `docker run --gpus all` / `--runtime=nvidia`.
+      hostConfig.Runtime = 'nvidia';
+      hostConfig.DeviceRequests = [
+        { Driver: 'nvidia', Count: -1, Capabilities: [['gpu']] },
+      ];
+    }
+
     const spec = {
       Image: image,
-      Env: [...env, `PORT=${capturePort}`],
+      Env: sidecarEnv,
-      HostConfig: {
+      HostConfig: hostConfig,
-        NetworkMode: 'host',
-        Privileged: true,
-        Binds: binds,
-      },
     };
 
     const createRes = await dockerApi('POST', '/containers/create', spec);