diff --git a/transcode_bench.py b/transcode_bench.py
index 130ce2d..544b6ae 100755
--- a/transcode_bench.py
+++ b/transcode_bench.py
@@ -13,6 +13,7 @@ import threading
 import argparse
 import signal
 import atexit
+import math
 from pathlib import Path
 from typing import Optional, Tuple, List
 
@@ -539,14 +540,13 @@ class Benchmark:
         max_streams = 1
 
         # Estimate maximum possible streams based on single stream performance
-        # If 1 stream achieves X fps, we can theoretically handle X/min_fps streams
-        # Use 80% of theoretical max to account for overhead
-        theoretical_max = int((avg_fps / min_fps) * 0.8)
+        # Upper bound = ceiling(1.2 * X / min_fps)
+        estimated_max = math.ceil(1.2 * avg_fps / min_fps)
 
-        # Cap the search space reasonably
-        estimated_max = max(2, min(theoretical_max, 128))
+        # Cap the search space reasonably (at least 2, at most 128)
+        estimated_max = max(2, min(estimated_max, 128))
 
-        print(f"Estimated capacity: ~{theoretical_max} streams (searching up to {estimated_max})")
+        print(f"Estimated capacity: ~{int(avg_fps / min_fps)} streams (searching up to {estimated_max})")
 
         # Binary search bounds
         low, high = 2, estimated_max
@@ -579,8 +579,8 @@ def main():
     parser.add_argument(
         '--duration',
         type=int,
-        default=30,
-        help='Test video duration in seconds (default: 30)'
+        default=10,
+        help='Test video duration in seconds (default: 10)'
     )
     parser.add_argument(
         '--input',