[mythtv-users] Adventures in Wireless HD

Phil Linttell phil.linttell at rogers.com
Tue Feb 8 22:41:26 UTC 2011


For Christmas I received a new NetGear WNDR3700 gigabit simultaneous
dual-band wireless-N router (it was the gigabit switch I wanted, I don't
use the 5GHz band for anything yet), and upgraded my combined FE/BE.  I
used the old hardware (Asus M3N78-VM with integrated nVIDIA 8200, Athon
X2 3GHz CPU, and 4GB RAM), and a single-band 802.11n (2.4GHz) PCI card
to upgraded my wife's Windows XP desktop.

Once I had everything up and working again, I tried the 0.24 Windows
myth front-end on her PC just for fun, with the result I pretty much
expected over wireless-N....  choppy HD video.  Unwatchable.

Then a couple of days ago, the WNDR3700 received a firmware update
(V1.0.7.98NA) and all-of-a-sudden I could play very steady HD video on
her machine with no other changes (not perfect, but watchable.)   Even
1080i 5.1 HD-PVR recordings, recorded with maximum quality settings (a
file over 5GB for a 1-hour recording.)   I had thought I'd only achieve
that result over wireless, if at all, with 5GHz streaming. 

This got me thinking... maybe I could get the Windows mythfrontend to
work on my sons' new Acer Aspire V5252 Windows 7 64-bit laptops (15.4",
AMD 2.3GHz V140, ATI HD 4250, 3GB RAM, integrated single-band 802.11n). 
These machines were about $350 and have HDMI out.  (My sons each have
external 24" 1080p HDMI monitors.)  Unfortunately, playback was very
stuttery/unwatchable - even sitting in the same room as the router.  

I then tried downloading the video file over Samba..... just to get a
feel for what sort of transfer rate I was playing with.  The 5GB HD-PVR
recording downloaded to one of the laptops in a little over six
minutes.... not bad for a 1-hour recording!   It played perfectly under
Windows Media Player, de-interlaced and all.   My next test was to try
playing the same video in WMP over UPnP/DNLA from the back-end.   It
would play flawlessly for several minutes, but then WMP would stop
altogether.   I could re-start the video from the beginning, but
playback would fail again after a several minutes.  

Still, it was enough to tell me that the wireless network wasn't the
reason the video was stuttering in Myth.   My next thought was to try
XBMC over UPnP.   I installed XBMC, configured mythtv as a UPnP
source... and the video played smoothly to completion.   Only problem
was de-interlacing....  I couldn't figure out how to configure it under
XBMC....  sometimes the video looked clean, other times it was badly
interlaced.   Also, of course, no commercial skip and the available
binaries don't support the 0.24 myth protocol directly.

Not sure what to try next on the laptops... I  just thought I'd share my
experiences up to now.  Particularly my surprise at getting 1080i
streaming working over 2.4GHz 802.11n to mythfrontend on Windows XP.  
Not that I'd recommend anyone use wireless for an HTPC, but it would be
great to get it working for my sons' laptops.

I might:
1. try to figure out if WMP was dying because of myth, or some other
reason (the router has a built-in UPnP server I can try); or
2. grab the frontend log from the laptops and see if anyone can suggest
why playback is stuttering; or
3. wait for XBMC 10.1 which I think is supposed to support 0.24 myth
protocol....  and figure out how to get de-interlacing to work.

Any votes?  ;-)

I don't think here's any point in booting the laptops with a live CD
since it's an ATI video chipset.  At some point, I'll probably do some
testing with a 5GHz USB dongle, but at the moment I don't think there's
a problem with 2.4GHz.

Phil



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