[mythtv] stuttering liveTV playback on remote frontend

[James Warden]

Hello,

I submitted this issue to the users list but to no
avail. Maybe some
developers can help me understand what's going on.

I have a b/e that is running debian unstable, kernel
2.6.20 (custom
build). It is really stable and I use it as a
multimedia data server, so not only for
mythtv. I have a few f/e (laptops mostly). I recently
installed debian
unstable + mythfrontend that comes from
debian-multimedia.org (some
recent svn version about 3 weeks old IIRC) on all my
laptops. While it works
great on 2 of the laptops I manage, the same setting
is showing a problem with
one of them with liveTV. While I can play recordings
without any problem over
my wireless-g network on all my f/e's, liveTV playback
is defective on this one
laptop. The log messages are as follows :

++++
2007-03-13 19:31:31.873 Checking to see if there's a
new livetv program to switch to..
2007-03-13 19:31:31.904 NVP: Prebuffer wait timed out
10 times.
2007-03-13 19:31:33.123
RingBuf(/multimed/mythtv/livetv/1029_20070313193235.mpg):
Waited 1.0 seconds for data to become available
...
2007-03-13 19:31:33.123 Checking to see if there's a
new livetv program to switch to..
2007-03-13 19:31:33.524 NVP: Prebuffer wait timed out
10 times.
2007-03-13 19:31:34.070 NVP: prebuffering pause
2007-03-13 19:31:34.612
RingBuf(/multimed/mythtv/livetv/1029_20070313193235.mpg):
Waited 1.0 seconds for data to become available
...
2007-03-13 19:31:34.612 Checking to see if there's a
new livetv program to switch to..
2007-03-13 19:31:35.690 NVP: Prebuffer wait timed out
10 times.
2007-03-13 19:31:36.046
RingBuf(/multimed/mythtv/livetv/1029_20070313193235.mpg):
Waited 1.0 seconds for data to become available
...
2007-03-13 19:31:36.046 Checking to see if there's a
new livetv program to switch to..
2007-03-13 19:31:36.922 TV: Attempting to change from
WatchingLiveTV to None
2007-03-13 19:31:37.310 NVP: Prebuffer wait timed out
10 times.
+++++
...
on and on

The laptop is intel based, lspci output is :

++++
00:00.0 Host bridge: Intel Corporation Mobile
915GM/PM/GMS/910GML Express Processor to DRAM
Controller (rev 03)
00:02.0 VGA compatible controller: Intel Corporation
Mobile 915GM/GMS/910GML Express Graphics Controller
(rev 03)
00:02.1 Display controller: Intel Corporation Mobile
915GM/GMS/910GML Express Graphics Controller (rev 03)
00:1d.0 USB Controller: Intel Corporation
82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #1 (rev
03)
00:1d.1 USB Controller: Intel Corporation
82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #2 (rev
03)
00:1d.2 USB Controller: Intel Corporation
82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #3 (rev
03)
00:1d.3 USB Controller: Intel Corporation
82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #4 (rev
03)
00:1d.7 USB Controller: Intel Corporation
82801FB/FBM/FR/FW/FRW (ICH6 Family) USB2 EHCI
Controller (rev 03)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI
Bridge (rev d3)
00:1e.2 Multimedia audio controller: Intel Corporation
82801FB/FBM/FR/FW/FRW (ICH6 Family) AC'97 Audio
Controller (rev 03)
00:1e.3 Modem: Intel Corporation 82801FB/FBM/FR/FW/FRW
(ICH6 Family) AC'97 Modem Controller (rev 03)
00:1f.0 ISA bridge: Intel Corporation 82801FBM (ICH6M)
LPC Interface Bridge (rev 03)
00:1f.1 IDE interface: Intel Corporation
82801FB/FBM/FR/FW/FRW (ICH6 Family) IDE Controller
(rev 03)
00:1f.3 SMBus: Intel Corporation 82801FB/FBM/FR/FW/FRW
(ICH6 Family) SMBus Controller (rev 03)
02:01.0 CardBus bridge: Texas Instruments PCI1510 PC
card Cardbus Controller
02:03.0 Network controller: Broadcom Corporation
BCM4318 [AirForce One 54g] 802.11g Wireless LAN
Controller (rev 02)
02:08.0 Ethernet controller: Intel Corporation
82562ET/EZ/GT/GZ - PRO/100 VE (LOM) Ethernet
Controller Mobile (rev 03)
++++

I do have some successful liveTV playback but not for
very long (sometimes
10sec, sometimes 5mn), the stuttering comes back
unavoidably.

I monitored the bandwidth when watching an
uncompressed recorded 
program
and liveTV. The receiving rate shows a difference of a
factor 3 when
liveTV exhibits the problem. When liveTV works (even
for just 1mn), the receiving rate is the same as when
I play recorded shows.  

I have no clue as to what could cause this. The only
difference between
recorded programs and liveTV is that I use NFS for
everything that is
read from disk, and I do not let the b/e stream
recorded programs. 

If you have already seen this kind of log messages and
can give me a hint, I would really appreciate.
Otherwise, I can provide any log or info you need to
uncover the root cause.

many thanks,
J.


 
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