fix(deltacast-bridge): use group-0 sample count as authoritative audio length

Taking the MAX sample count across the 4 audio groups could emit more audio
frames per slot than group 0 (the SDI-clock reference), drifting the audio
stream slightly longer than video — heard as a ~1% pitch-up. Group 0 paces the
timeline exactly as the original 2ch path did; shorter groups are silence-padded
to its length, never extending it.

services/capture/deltacast-bridge/main.c

@@ -322,16 +322,17 @@ static void *audio_thread(void *arg) {
                     for (int g = 0; g < GROUPS; g++)
                         ai.pAudioGroups[g].pAudioChannels[0].DataSize = (ULONG)gbuf_sz;
                     if (VHD_SlotExtractAudio(slot, &ai) == VHDERR_NOERROR) {
-                        /* Frames present = bytes from the most-populated group
+                        /* Group 0 is the AUTHORITATIVE sample count — it paces the
-                         * divided by one stereo frame (4 bytes). Real SDI audio
+                         * audio timeline in lockstep with video (same SDI slot
-                         * is sample-aligned across groups; using the max keeps
+                         * clock), exactly as the original 2ch path did. We must
-                         * us robust if a quiet group returns fewer bytes. */
+                         * emit EXACTLY group 0's frame count per slot; taking a
+                         * max across groups would occasionally emit extra frames
+                         * and make the audio stream drift LONGER than the video
+                         * (heard as a slight pitch-up). Groups 1-3 are sampled at
+                         * the same rate; any that return fewer bytes are padded
+                         * with silence to group 0's length, never extending it. */
                         ULONG g0 = ai.pAudioGroups[0].pAudioChannels[0].DataSize;
                         size_t frames = (size_t)g0 / 4;   /* 2ch * s16 = 4 bytes/frame */
-                        for (int g = 1; g < GROUPS; g++) {
-                            size_t gf = (size_t)ai.pAudioGroups[g].pAudioChannels[0].DataSize / 4;
-                            if (gf > frames) frames = gf;
-                        }
                         if (frames > 0) {
                             size_t need = frames * FRAME_BYTES;
                             if (need > out_cap) { frames = out_cap / FRAME_BYTES; need = frames * FRAME_BYTES; }

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

@@ -276,6 +276,13 @@ async function reconcileRecordersForNode(node) {
   }
   if (ports.length === 0) return;
 
+  // Default master codec for newly-discovered ports. SDI capture at 1080p59.94
+  // CANNOT be encoded in realtime on CPU (ProRes/x264 fall behind → dropped
+  // frames → short, fast-playing files). Nodes with an NVENC-capable GPU default
+  // to GPU HEVC; only GPU-less nodes fall back to CPU ProRes.
+  const hasGpu = Array.isArray(cap.gpus) && cap.gpus.length > 0;
+  const defaultCodec = hasGpu ? 'hevc_nvenc' : 'prores_hq';
+
   for (const p of ports) {
     // INSERT … ON CONFLICT DO NOTHING: create-once. Never overwrite an existing
     // row (preserves label, enabled, codec config, status). source_config keeps
@@ -285,8 +292,9 @@ async function reconcileRecordersForNode(node) {
       : { device: p.device_index };
     await pool.query(
       `INSERT INTO recorders
-         (node_id, device_index, source_type, source_config, name, enabled, auto_provisioned)
+         (node_id, device_index, source_type, source_config, name, enabled, auto_provisioned,
-       VALUES ($1, $2, $3::source_type, $4, $5, false, true)
+          recording_codec, recording_container, recording_video_bitrate, recording_audio_channels)
+       VALUES ($1, $2, $3::source_type, $4, $5, false, true, $6, 'mov', '25M', 2)
        ON CONFLICT (node_id, device_index) WHERE node_id IS NOT NULL AND device_index IS NOT NULL
        DO NOTHING`,
       [
@@ -296,6 +304,7 @@ async function reconcileRecordersForNode(node) {
         JSON.stringify(srcCfg),
         // Deterministic hardware name; the operator can set a friendly `label`.
         `${node.hostname}-${p.source_type === 'deltacast' ? 'dc' : 'bmd'}${p.device_index}`,
+        defaultCodec,
       ]
     );
   }