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Poor Reception on 5500
PostPosted: Sat Jan 24, 2009 10:21 pm Reply with quote
pbennett45
 
Joined: 24 Jan 2009
Posts: 4




So I don't have a TV that is HD anyway. So I'm just using the 5500 to get ATSC digital channels, don't care about hd or not. Currently, I'm getting blocky on and off reception on channels that my $40 set top box I got with the gov't coupon is receiving fine. My 5500 is in the PC and displaying on my monitor. Is it possible that because the set top box is only outputing SD, it can handle a higher bit error rate than the 5500 which is trying to output for my PC monitor? If so, how can I setup my 5500 to just decode a standard definition 640x480 stream? BTW - it's a mythbuntu 8.10 install, with an old Gefore4 mx video card - using the default drivers for now. Also of note.. the channels that aren't transmitted in HD (like the NBC Universal sports channel, and the networks' weather channels) are coming in just fine, which seems to support my theory that if I could tell it not to bother trying to decode the HD stream for the main channels it'd be fine. Anyone know if that's true? Thanx!
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PostPosted: Sat Jan 24, 2009 10:23 pm Reply with quote
pbennett45
 
Joined: 24 Jan 2009
Posts: 4




Oh yea... also.. it's a crappy antenna the window of an apartment... only plus is i'm only a few miles from most of the towers. I know, not ideal for hdtv... but like i said.. i don't care about hdtv, and for digital sdtv my $40 set top box seems to be just fine with it.
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PostPosted: Fri Feb 13, 2009 1:06 pm Reply with quote
rfeese
 
Joined: 13 Feb 2009
Posts: 2




I have found that my HD-5500 card had pretty good reception just using a cheap set of rabbit-ears. However, playing back HD takes significant resources. You need a fast processor and/or video acceleration. I sometimes get stuttering and skipping when playing back video.

I don't think you can set the card to scale to SD. You could record shows to your HD using MythTV or something and then scale those afterwards -- it takes a lot of CPU but doesn't have to be real-time.
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PostPosted: Thu Feb 19, 2009 8:12 pm Reply with quote
pbennett45
 
Joined: 24 Jan 2009
Posts: 4




Don't think it's a playback issue... I've got that problem too, but they have distinctly different symptoms... getting the blocks of color and pixelation... I occasionally see it with my cheap-o $40 set top box when the weather's bad, but it's constant with most channels on the PCHDTV...

Also, if I use the dtvsignal tool, I can drive both with essentially the same signal (rabbit ears >> 2 way split >> one side to set top one side to pchdtv) and my set top box is showing 80% signal strength while the pchdtv shows less than 50....

I'm starting to wonder if some decoder chips are just better designed for poor signal quality environments...
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PostPosted: Tue Mar 03, 2009 8:44 pm Reply with quote
pbennett45
 
Joined: 24 Jan 2009
Posts: 4




Some additional notes / questions. First - I noticed that it improved a little bit when I moved my computer into the living room and used the same short cable my $40 dtvPal is on.. still not great though. And when I put the 50 foot cable on the dtvpal it doesn't notice the difference, still has a perfect signal.

Also, I used atscget to capture the transport stream, then ran it through mencoder in non-realtime and played back the decoded waveform... still have many more problems than are visible with the set top box. So I know now for sure it's my an mpeg decoding problem.

So it definitely would seem that EITHER the ST Micro STV0373 chip (in the dtvPal) handles a crummy multi-path ridden urban signal better than the LG DT3303 chip (on the 5500) OR the ST processor/mpeg decoder is handling the errors in such a way that they are not evident on an SDTV. A couple of questions for whoever might know

1) Does the LGDT3303 chip on the 5500 handle the RS forward error correction? If so, does it still pass on the FEC bytes in the transport stream so when there are un-fixable errors the software running on the PC could feasibly be aware of them?

2) Do any of the linux MPEG decoders look of this error data in the transport stream (if it's even there and not stripped out) ?
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PostPosted: Wed Jul 08, 2015 4:07 am Reply with quote
Nuzzle
 
Joined: 08 Jul 2015
Posts: 5




In order to get it working on the regular kernel, I had to remove any mention of dvb and video from the lib/lib64 directories, download the 5500 driver, make, make install and all was well. I try the same thing with the smp kernel and I get the analog device just fine, but never any /dev/dvb. We offer best quality Electronic Gadgets test papers and Text books and Islamic Apps materials. You can get our Games 100% guaranteed Islamic Devices. Looks like the correct stuff is loaded into /lib/modules/2.6.17-1.2142_FC4smp/kernel/drivers/media/video/ and /lib/modules/2.6.17-1.2142_FC4smp/kernel/drivers/media/dvb/ (by comparing the file names to the modules that are working in my other kernel). Any advice on getting this to work or any known issues with smp as to why it wouldn't work?
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Poor Reception on 5500
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