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strong signals but hd-3000 dropping frames
PostPosted: Sun Nov 21, 2004 3:36 pm Reply with quote
statman
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I have just installed an HD-3000 in a Athlon XP 2500+ system with an Nvidia Nforce 2 chipset. I have 5 digital stations broadcasting from within 6 miles of where I live, 4 from the same tower and one from a tower that is nearly in the same direction. I installed a short-range directional antenna (SR15) from antennasdirect.com and oriented it towards the tower with the four stations.

I installed the kernel modules in my 2.6.7 kernel and it can recognize the card. Running dtvsignal shows a signal strength in excess of 95 for all the channels. Some of the channels consistently give a signal strength of 100. However, the playback using xine keeps complaining of excess number of dropped frames and the video is very choppy with frequent pixelation artifacts. Something like a football game is essentially unwatchable because of the jumpiness.

I tried using getatsc and then playing the recorded stream with xine but it was still very choppy.

Any suggestions on where to start trying to improve the performance? I ran xine-check and everything there checks out as "good". I am using the XvMC video-out device with the Nvidia proprietary XFree86 driver.

Should I concentrate on trying to get a cleaner signal, perhaps by installing an amplifier or an antenna with better gain? Should I play with the orientation of the antenna or should I be looking at the computer performance instead?
try mplayer
PostPosted: Sun Nov 21, 2004 3:54 pm Reply with quote
mspice
 
Joined: 03 Nov 2004
Posts: 36




try mplayer:

Code:
mplayer /dev/dtv -cache 8192 -tsprog 1

-tsprog = the subchannel you want to tune to.  Just try 0,1,2,3 until you get the HD one you are looking for.


I cannot get xine to play worth crap. Mplayer can play it without a a special version. If you compile it with --enable-xvmc then you can also try out that acceleration by adding these options:
Code:
-vo xvmc -vc ffmpeg12mc
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Re: strong signals but hd-3000 dropping frames
PostPosted: Sun Nov 21, 2004 5:54 pm Reply with quote
pdicamillo
 
Joined: 09 Mar 2004
Posts: 68
Location: Needham, MA




statman wrote:
I tried using getatsc and then playing the recorded stream with xine but it was still very choppy.


Have you tried using dtvstream instead of getatsc? According to another thread, when you use getasc with the HD-3000, after every 512 packets there are 4 packets of bad data. Dtvstream also reads the bad data and complains about it, but will discard it. Dtvstream is at:

http://www.buzzlabs.com/~peter/dtvstream-linux-1.0b2.tar.gz
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Re: strong signals but hd-3000 dropping frames
PostPosted: Mon Nov 22, 2004 12:48 pm Reply with quote
inkling
 
Joined: 05 Feb 2004
Posts: 342




pdicamillo wrote:
statman wrote:
I tried using getatsc and then playing the recorded stream with xine but it was still very choppy.


Have you tried using dtvstream instead of getatsc? According to another thread, when you use getasc with the HD-3000, after every 512 packets there are 4 packets of bad data. Dtvstream also reads the bad data and complains about it, but will discard it. Dtvstream is at:

http://www.buzzlabs.com/~peter/dtvstream-linux-1.0b2.tar.gz


Could be a driver problem if dtvstream is seeing it too. pchdtvr doesn't bother with filtering so it might affect me as well. Won't know until I get my HD3000 in to test it with.
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Thanks for the suggestions
PostPosted: Mon Nov 22, 2004 1:41 pm Reply with quote
statman
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Especially for the suggestion to use mplayer instead of xine. I picked up the script for a getatsc to mplayer pipe that was posted in this forum on another thread and that is working very well.

I am using the Debian (unstable) distribution and the mplayer from the Debian package works well on the output from getatsc. It is recommended that I recompile it on this system and I will do so. Right now I am trying to resolve the problem of why /proc/mtrr is not set properly by the XFree86 driver. I would like to have mtrr support when using mplayer.

In any case, the output from getatsc behaves much better with mplayer than does the output from dtvstream.
Re: Thanks for the suggestions
PostPosted: Mon Nov 22, 2004 6:41 pm Reply with quote
pdicamillo
 
Joined: 09 Mar 2004
Posts: 68
Location: Needham, MA




statman wrote:
In any case, the output from getatsc behaves much better with mplayer than does the output from dtvstream.


What kind of problem do you have with the output from dtvstream? If you use dtvstream with the "-p all" option it will include all the packets, and you still benefit from its buffering and other features. Does that eliminate the problem?
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strong signals but hd-3000 dropping frames
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