diff --git a/panasonic.py b/panasonic.py
index 0d69935..dd98068 100755
--- a/panasonic.py
+++ b/panasonic.py
@@ -154,8 +154,9 @@ def getInitialTSFromBuffer(content, delta=0.1):
     logger = logging.getLogger(__name__)
 
     logger.debug('Determining initial timestamp from content')
+    length = len(content)
     with Popen(['ffprobe','/dev/stdin','-loglevel', 'quiet', '-read_intervals', ('0%%+%f' % delta), '-show_entries', 'frame=frame_no,best_effort_timestamp_time', '-of','json'], stdout=PIPE, stdin=PIPE) as ffprobe:
-        out, _ = ffprobe.communicate(input=content)
+        out, _ = ffprobe.communicate(input=content[0:min(length,200000)])
         frames = json.load(BytesIO(out))
         logger.debug('Frames: %s' % frames)
         if 'frames' in frames: