diff --git a/services/capture/src/capture-manager.js b/services/capture/src/capture-manager.js
index 67cee91..92220a6 100644
--- a/services/capture/src/capture-manager.js
+++ b/services/capture/src/capture-manager.js
@@ -134,6 +134,9 @@ const VIDEO_CODECS = {
   //
   // -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 required, use prores_hq (CPU).
+  // GROWING-file variant: every frame an IDR (all-intra) so a still-growing
+  // file is decodable to its last complete frame. This is HEAVY — only used when
+  // growing-files is on (see hevcNvencArgs()).
   hevc_nvenc:   {
     args: ['-c:v', 'hevc_nvenc', '-preset', 'p4', '-rc', 'vbr', '-bf', '0', '-forced-idr', '1', '-g', '600', '-force_key_frames', 'expr:1', '-profile:v', 'main10'],
     bitrateControl: true,
@@ -141,6 +144,27 @@ const VIDEO_CODECS = {
   },
 };
 
+// HEVC/NVENC encode args, GOP structure chosen by mode.
+//   growing=false (normal record): efficient long-GOP (2s @ fps) HEVC. NVENC
+//     easily sustains 1080p59.94 10-bit here, so no frame drops → audio/video
+//     lengths stay locked. This is the DEFAULT for recorders.
+//   growing=true (edit-while-record): ALL-INTRA (every frame an IDR) so the
+//     growing file is decodable to its last written frame — the requirement for
+//     Premiere's growing-file refresh. Much heavier, only used when needed.
+// `force_key_frames expr:1` (all-intra) is the ~4× compute path that was
+// crippling realtime when applied to every recording; gating it on `growing`
+// is the fix for the dropped-frame A/V drift.
+function hevcNvencArgs(framerate, growing) {
+  const base = ['-c:v', 'hevc_nvenc', '-preset', 'p4', '-rc', 'vbr', '-profile:v', 'main10'];
+  if (growing) {
+    return [...base, '-bf', '0', '-forced-idr', '1', '-g', '600', '-force_key_frames', 'expr:1'];
+  }
+  // Normal long-GOP: ~2s keyframe interval, 2 B-frames. Realtime-friendly.
+  const fps = Number.parseFloat(framerate) || 60;
+  const gop = Math.max(2, Math.round(fps * 2));
+  return [...base, '-bf', '2', '-g', String(gop)];
+}
+
 // nvenc codecs available in the capture image. Used both to validate the master
 // codec and (issue #164) as the GPU-availability signal for the HLS preview.
 const NVENC_CODECS = new Set(['h264_nvenc', 'hevc_nvenc']);
@@ -479,7 +503,14 @@ function buildEncodeArgs({
   const args = [];
   if (isNetwork) args.push('-map', '0:v:0?', '-map', '0:a:0?');
 
-  args.push(...v.args);
+  // hevc_nvenc GOP structure is mode-dependent: all-intra only for growing
+  // files, efficient long-GOP for normal record (so NVENC stays realtime and
+  // doesn't drop frames). All other codecs use their static arg set.
+  if (codec === 'hevc_nvenc') {
+    args.push(...hevcNvencArgs(framerate, growing));
+  } else {
+    args.push(...v.args);
+  }
   if (v.pixFmt) args.push('-pix_fmt', v.pixFmt);
   if (v.bitrateControl && videoBitrate) args.push('-b:v', videoBitrate);
   if (framerate && framerate !== 'native') args.push('-r', framerate);