Configure GPU encoder for low-latency (no B-frames)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

streaming/gpu_output.py

@@ -96,8 +96,12 @@ class GPUEncoder:
         # Create dummy video to get frame buffer template
         self._init_frame_buffer()
 
-        # Create encoder
-        self.encoder = nvc.CreateEncoder(width, height, "NV12", usecpuinputbuffer=False)
+        # Create encoder with low-latency settings (no B-frames for immediate output)
+        self.encoder = nvc.CreateEncoder(
+            width, height, "NV12", usecpuinputbuffer=False,
+            bf=0,             # No B-frames - immediate output
+            lowLatency=1,     # Low latency mode
+        )
 
         # CUDA kernel grid/block config
         self._block = (16, 16)