+def filesize_from_tbr(tbr, duration):
+ """
+ @param tbr: Total bitrate in kbps (1000 bits/sec)
+ @param duration: Duration in seconds
+ @returns Filesize in bytes
+ """
+ if tbr is None or duration is None:
+ return None
+ return int(duration * tbr * (1000 / 8))
+
+