diff --git a/cht/stream/manager.py b/cht/stream/manager.py
index 25e6629..620f303 100644
--- a/cht/stream/manager.py
+++ b/cht/stream/manager.py
@@ -10,6 +10,7 @@ Architecture:
 
 import json
 import logging
+import os
 import re
 import time
 from queue import Queue, Empty
@@ -266,8 +267,11 @@ class StreamManager:
             frame_num = start_number
             offset = self.current_global_offset
             buf = b""
+            raw_fd = proc.stdout.fileno()
             while True:
-                chunk = proc.stdout.read(4096)
+                # os.read on the raw fd returns as soon as ANY data is available
+                # (no Python buffered-IO blocking waiting to fill a buffer)
+                chunk = os.read(raw_fd, 65536)
                 if not chunk:
                     break
                 buf += chunk