disable timeshift make choppy livetv effect (1 Viewer)

[Sentinel]

Audio Codec: MPA Decoder Filter
Video Codec: MPV Decoder Filter
CPU Type: AMD Sempron 2800+
Memory: 511 MB
Motherboard: 'K8N' (ASUSTeK Computer INC.)
TV Card Model: Avermedia m150
TV Card Type: Hardware
TV Card Driver: Version 1.0.6.19 (11/18/2005,1.0.6.19)
Video Card Model: Radeon 9550 (omega 3.8.231) (128 MB)
Video Card Resolution: 1024x768
Video Render Type: VMR9
Audio Card Model: Realtek AC'97 Audio

Mystery but with timeshift all function normal no more choppy livetv, without timeshift come the trouble.

I try with the latest SVN but same effect. When I disable the timeshift after channel changing come the choppy effect.But when I enable the timeshift no errors, no choppy effect.

Here is the log

http://www.testteam-mediaportal.com/Joomla/forum/attachment.php?attachmentid=561&d=1149783965

and here is the Log Scenario:
-Mp starting
-Select mytv
-Timeshift On
-Fullscreen all ok
-back to TV window Timeshift disable
-Fullscreen all ok
-Switch another channel all ok
-Switch to second channel-> come the choppy livetv effect