[mythtv] stuttering liveTV playback on remote frontend

Wed Mar 14 01:22:33 UTC 2007

Hello James,

  I've seen this on my system also (tho my network is entirely 
wired and Gigabit, except for the 100Mbit interface on the FE,
and I only allow the Myth streaming protocol - no network 
shares) - and it's been discussed with a couple of Dev's 
looking at ways to resolve the issue (I don't recall a specific 
outcome - I thought patches had been added into SVN for 
future Myth versions, but I'm not sure).  

  However, if, while you're watching Live TV, you skip back 
a couple of seconds, you'll probably find that the stuttering 
doesn't occur - I've had success with this method (actually
suggested to me by a Tivo user, after hearing me describe the
problem).  It makes watching any given Live channel viable for
a reasonable period of time (like an entire episode).

  We're mostly using Myth to act as a VCR, watching Live
content via the analogue set, until this comes good in a future
version.

----- Original Message -----
>From: "James Warden" <warjamy at yahoo.com>
>To: <mythtv-dev at mythtv.org>
>Subject:  [mythtv] stuttering liveTV playback on remote frontend
>Date: Tue, 13 Mar 2007 19:25:11 -0700
>
> 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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--
Ian Latter
Late night coder ..
http://midnightcode.org/