Update transcode_bench.py

transcode_bench.py

@@ -370,9 +370,13 @@ class TranscodeJob:
             self.fps = self._parse_fps(stderr)
             self.success = self.process.returncode == 0
 
+            # Store stderr for debugging
+            self.stderr = stderr
+
         except Exception as e:
             self.success = False
             self.end_time = time.time()
+            self.stderr = str(e)
 
     def _parse_fps(self, ffmpeg_output: str) -> float:
         """Parse average FPS from FFmpeg output."""
@@ -432,6 +436,14 @@ class Benchmark:
             avg_fps = sum(job.fps for job in jobs) / len(jobs) if jobs else 0.0
             return True, avg_fps
 
+        # If failed, print first error for debugging
+        for job in jobs:
+            if not job.success and hasattr(job, 'stderr'):
+                # Only print first few lines of error
+                error_lines = job.stderr.split('\n')[:5]
+                print(f"\n  Debug - First error: {' '.join(error_lines)}")
+                break
+
         return False, 0.0
 
     def find_max_streams(self, min_fps: float = 30.0) -> int:
@@ -442,9 +454,23 @@ class Benchmark:
         print(f"\nBenchmarking with {self.accel_name}...")
         print("Finding maximum simultaneous 1080p streams at real-time or better...\n")
 
+        # First verify that 1 stream works
+        print(f"Testing 1 simultaneous stream...", end=' ', flush=True)
+        success, avg_fps = self.run_parallel_transcodes(1)
+
+        if not success:
+            print(f"✗ (failed)")
+            return 0
+
+        if avg_fps < min_fps:
+            print(f"✗ (avg {avg_fps:.1f} fps - below real-time)")
+            return 0
+
+        print(f"✓ (avg {avg_fps:.1f} fps)")
+        max_streams = 1
+
         # Binary search bounds
-        low, high = 1, 64
-        max_streams = 0
+        low, high = 2, 64
 
         while low <= high:
             mid = (low + high) // 2