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Some stations work okay and others don't
PostPosted: Fri Apr 18, 2008 7:03 pm Reply with quote
jsedwards
 
Joined: 18 Apr 2008
Posts: 11




I am in salt lake city, utah and I have just started using the pchdtv-5500. I have tried all of the stations that I can find and some of them seem to work fine and others are flakey at best.

Of the big three, KTVX (ABC) and KUTV (CBS) seem to work pretty well. The third KSL (NBC) is quite shakey. Most of the time I get an excellent video, but no audio. A couple of times I have gotten audio but the video was totally pixellated and I couldn't even tell what it was. One time I got both video and audio but it didn't seem like the normal broadcast, it had the regular 4:3 picture but next to it was some advertisements and underneath it has scrolling weather or something.

Then I notice in this list that I made a couple of weeks ago (I don't remember how I made it now):

KUTV-DT:593000000:VSB_8:0x11:0x14:0x01
KUEN___:605000000:VSB_8:0x21:0x24:0x02
MHzWrld:605000000:VSB_8:0x31:0x34:0x03
KUER-FM:605000000:VSB_8:0x5b1:0x5b4:0x5b
KSL-HD_:617000000:VSB_8:0x31:0x34:0x03
KSL-Wx_:617000000:VSB_8:0x41:0x44:0x04
KTVX-HD:629000000:VSB_8:0x11:0x14:0x01
HiveTV_:629000000:VSB_8:0x21:0x24:0x02
KUED___:641000000:VSB_8:0x21:0x24:0x02
KUED-HD:641000000:VSB_8:0x31:0x34:0x03
V-Me___:641000000:VSB_8:0x41:0x44:0x04
BYU-TV_:653000000:VSB_8:0x21:0x24:0x02
BYU-TVI:653000000:VSB_8:0x31:0x34:0x03
HDCreat:653000000:VSB_8:0x41:0x44:0x04

And I notice in this list that the stations I receive ok only have one thing listed for that frequency. The stations I am having trouble with (like KSL and BYU) have multiple things listed on the same frequency.

Just for grins I e-mailed KSL and asked them what was the deal? Surprisingly they answered me and they said that KTVX does multiple things on their frequency as well (and now I looked at the chart again and indeed that is true, I just didn't see it before). Their explanation was that I may have too much signal strength from them and that is overloading the receiver.

Using the dtvsignal and dtvsnr programs all three stations seem about equal (78 to 90 range). I also tried pointing the antenna in a different direction which seemed to drop the signal down a bit, but I got the same thing video but no audio. I tried it again with the antenna pointed in the best direction and this time I got sound but the video was pixellated and obvious for a completely different program (the audio was for a commercial and the video looked like a show).

I am kind of a newbie at this so anyone can offer any advice what to do next, it would be most appreciated.

Thanks
-Scott
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PostPosted: Fri Apr 18, 2008 7:19 pm Reply with quote
waterhead
 
Joined: 24 Apr 2005
Posts: 299




This seems like a reception problem. The signals can bounce off of things, giving you bad reception.

Are you surrounded by tall buildings or mountains? Sometimes you can actually get a bounced signal better than the original. Make sure that your antenna is pointed in the right direction. Refer to this site for antenna positioning.
http://www.antennaweb.org

What are you using to watch TV with? I would recommend MythTV. It is a bit overblown for just watching TV, but it works quite well. Another method is to use Kaffeine, but it needs a bit of configuring first.

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PostPosted: Fri Apr 18, 2008 8:05 pm Reply with quote
jsedwards
 
Joined: 18 Apr 2008
Posts: 11




I forgot to mention that I am just using the getatsc program to write the data into a file and then viewing it with Kaffeine. Since my first post I went back through all of the stations again and recorded each station for approximately a minute and got the following results:

28 (FOX?) Still picture for a few seconds, then color test pattern. No audio.
29 (?) Good video, no audio.
34 (KUTV-CBS): Excellent video and audio.
36 (UEN): Good video and audio.
38 (KSL-NBC): Got the weather thing again, this time without audio.
40 (KTVX-ABC): Excellent video and audio.
42 (KUED-PBS): Pixellated video, audio okay.
44 (KBYU-PBSHD): Excellent video and audio. Tried a second time and video was pixellated, but audio was okay I think.
46 (KJZZ): Excellent video and audio.
48 (?): Excellent video and audio.

So KUTV and KTVX have consistently worked good and KSL and KUED have never worked correctly for me. BYU worked once, but the other times it has
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PostPosted: Sat Apr 19, 2008 5:49 am Reply with quote
jsedwards
 
Joined: 18 Apr 2008
Posts: 11




Quote:
This seems like a reception problem. The signals can bounce off of things, giving you bad reception.

Are you surrounded by tall buildings or mountains? Sometimes you can actually get a bounced signal better than the original. Make sure that your antenna is pointed in the right direction. Refer to this site for antenna positioning. http://www.antennaweb.org


I went to that site a few weeks ago, but I thought I would check it again to verify. The antenna is definitely pointed in the right direction (225 degrees), but I should mention that it is an indoor antenna. I am 20 blocks (manhattan distance) NW of downtown SLC, so there are no tall buildings nearby.

Quote:
What are you using to watch TV with? I would recommend MythTV. It is a bit overblown for just watching TV, but it works quite well. Another method is to use Kaffeine, but it needs a bit of configuring first.


I tried to use MythTV but it had some unhappiness about the MySQL database thing. I fought with it for a while but since I don't want to use it as a permanent solution I hate to spend a bunch of time debugging it.

As I mentioned in my previous reply (which I started before your reply so I hadn't seen yours) I am using getatsc to store the data in a file and then using kaffeine to watch it.

Thanks again for the help.

-Scott
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PostPosted: Sat Apr 19, 2008 6:36 am Reply with quote
waterhead
 
Joined: 24 Apr 2005
Posts: 299




If you want to setup Kaffeine to view the channels directly, I think I could help you out with that. It has been a while since I did it, so I'll have to refresh my knowledge of it. I did record it in a post found [url=http://hftom.free.fr/phpBB2/viewtopic.php?p=501#501[here[/url].

Basically, you scan for channels using dvb-utils azap. You create a channels.conf file containing your channels. You then need to convert the file into something that Kaffeine can understand. That is done using this program, that you need to compile before you can use it.
http://websvn.kde.org/branches/work/~pfister/

I was unable to compile it on my Mythbuntu (Ubuntu) system because of a bug. I was able to do it on Suse, so I did the file converting on Suse and then copied it to my Mythbuntu machine.

You rename the file channels.dvb and put it in the hidden folder ~/.kde/share/apps/kaffeine. This is in your home folder.

I should tell you that you have to enable DVB in the Kaffeine configuration section.

I did have to tweak the settings in the xine engine section. I selected BOB deinterlacing and xv video driver. I also increased the video buffer to stabilize the HD playing.

_________________
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PostPosted: Mon Apr 21, 2008 6:51 am Reply with quote
jsedwards
 
Joined: 18 Apr 2008
Posts: 11




Thanks for the information. On the machine that has the pcHDTV card in it right now Kaffeine doesn't work correctly at all. (It is a Dell Inspiron 530 running Kubuntu-7.10.) Any video I try to play back stutters like crazy, even the video from my video camera. I wonder if it is the buffer in Kaffeine is too small, or if this machine is just too heavily loaded with not enough RAM. I have like 30 tabs open in Firefox, 8 shells in Konsole, 12 tabs in Konqueror, the GIMP, and XMMS all running.

Because I can't play the video on this machine I have been copying the files to my old AMD64 machine which seems to play it back fine.

Something just hit me while I was typing this, I wonder if this machine is too heavily loaded to record? Would it cause a problem if the machine was so heavily loaded that it couldn't keep up with the recording? I will try to move the card to the AMD64 machine in the next couple of days. It has twice as much RAM and I don't have to have any other applications running.

Thanks again,
-Scott
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PostPosted: Mon Apr 21, 2008 2:34 pm Reply with quote
waterhead
 
Joined: 24 Apr 2005
Posts: 299




Do you really need all of those things running while you are watching a video?

Recording may not be affected. As far as I know, digital recording just dumps the program to a file, no processing is done. Does this mean that it doesn't store anything in memory? I really don't know.

Usually, a media PC is a dedicated PC. This doesn't mean that you can't use it for other things, but media recording and playing should take priority. Stuttering can be from the video card driver. If it is not configured to unload some of the video processing to the video card, the CPU will max out and you get stuttering.

Open up a hardware monitor when running a video and take a look at the CPU. I use the KSysGuard program for this. Check your RAM and SWAP memory there too.

_________________
Mythbuntu 8.04
Intel D875PBZ main board
Pentium4 3.06Ghz
1024GB RAM
nVidia 6600GT
pcHDTV HD-3000
Air2PC PCI
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PostPosted: Tue Apr 22, 2008 5:01 am Reply with quote
jsedwards
 
Joined: 18 Apr 2008
Posts: 11




In retrospect it was maybe a bad idea to put the card in this machine. My plan was to record on this machine and have another machine dedicated to watching. My original thinking was that this machine stays on all the time and so I would never have to worry about making sure it was powered on to record some show.

I do development on this machine and I'm logged into my remote machine, and several online threads. I can't remember everything I'm working on, so I like to keep all the threads separate so I know what I've been doing on a particular project. Someday I plan to fix Bash so that it can keep the history on multiple shells separate Wink

Up until last year (07-07-07) I kept 3 or 4 machines all running all the time, but to try to reduce my carbon footprint, I have reduced it down to just leaving this one on all the time.

It occurred to me yesterday that the lack of memory in this machine may be causing other problems I have had. I have been complaining for months on the Ubuntu forums about Firefox hanging on this machine whenever watching Flash videos. I have been blaming the Ubuntu 7.10 release because I bought this machine just after it was released so I installed it. Flash played fine on my old machine with 7.04. It occurred to me yesterday, that the problem might not be with Ubuntu 7.10 but lack of RAM in this machine. I am wondering if the famous Linux OOM Killer is being loosed on some processes?

So I decided I will go buy some more RAM today and give that a try. If that doesn't work I will have to clean off the disk on the old machine and try the pcHDTV card in there. (That was another reason I didn't put the pcHDTV card in the old machine is that it's hard drive only has 5GB of space left. I haven't had time to verify absolutely everything on it is backed up before I reformat it.)
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PostPosted: Wed Apr 23, 2008 7:10 am Reply with quote
jsedwards
 
Joined: 18 Apr 2008
Posts: 11




The addition of RAM only seemed to help marginally. Out of a dozen tests I only got pixellated video one time (before it was more often than not). But other than that there doesn't seem to be any difference. I was also recording without any other apps running, just a Konsole.

I also tried running Kaffeine on it again and it too seemed marginally better, it didn't stutter quite as much but it still stuttered. I also tried to watch it directly in Kaffeine but I couldn't figure out how to set any of that up. There are screenshots of the Kaffeine help and what I had here:
http://www.itsallgoodradio.com/snapshot1.png
http://www.itsallgoodradio.com/snapshot2.png

Someone at KSL sent me a chart of the stations in Salt Lake City and what streams they are sending. (I don't have access to it right now or I would post it too). But in looking at it, I would say that (more or less) the stations that are sending more streams are the ones I am having trouble with. The stations that are not transmitting as much are the ones I seem to receive without problems.

I can't figure out why Kaffine stutters on the Intel Core Duo machine (bogomips 3591.00 - 3GB RAM - Kubuntu 7.10), but is smooth as glass on the AMD64 machine (bogomips 2990.08 - 512MB RAM - Kubuntu 7.04) playing the same file.

I would like to have a better understanding of how all this fits together. Is there a good description somewhere of the format of the data that getatsc is storing is? I read in another post on this forum that getatsc stores all of the streams that are on a channel. If that is the case how does Kaffeine select which one to play?

Thanks again for your help.
-Scott
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PostPosted: Wed Apr 23, 2008 2:07 pm Reply with quote
waterhead
 
Joined: 24 Apr 2005
Posts: 299




I can't help with getatsc, I never use it. The difference between the two systems is not so much the CPU, as the video processor. That can make a huge difference. And, for both ATI and nVidia, the stock linux drivers don't cut it. You need to download and install the drivers from the manufacturers web site.

_________________
Mythbuntu 8.04
Intel D875PBZ main board
Pentium4 3.06Ghz
1024GB RAM
nVidia 6600GT
pcHDTV HD-3000
Air2PC PCI
MythTV 0.21
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PostPosted: Thu Apr 24, 2008 6:46 am Reply with quote
jsedwards
 
Joined: 18 Apr 2008
Posts: 11




That occurred to me while I was laying there not sleeping this morning Sad

So I installed the nvidia driver, but it naturally won't startx now. Says it can't open the /dev/nvidia0 device file. I have been searching around for the solution but no luck so far.
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PostPosted: Thu Apr 24, 2008 3:50 pm Reply with quote
waterhead
 
Joined: 24 Apr 2005
Posts: 299




In the PC's that I have nVidia cards in, I have the /dev/nvidia0 file.

Maybe it didn't install correctly. You could try re-installing it, but first remove the installation with the --uninstall option.

You also may be able to install a precompiled binary from your distros repository. This is not the same as the stock "nv" driver that is used by default. For Kubuntu, it should be part of the Restricted Drivers Manager section.

_________________
Mythbuntu 8.04
Intel D875PBZ main board
Pentium4 3.06Ghz
1024GB RAM
nVidia 6600GT
pcHDTV HD-3000
Air2PC PCI
MythTV 0.21
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PostPosted: Fri Apr 25, 2008 4:22 am Reply with quote
jsedwards
 
Joined: 18 Apr 2008
Posts: 11




That's the rub, it has the /dev/nvidia0 device file. I couldn't see anything wrong with it. It looked correct to me.

I posted a request for help on the Ubuntu forum http://ubuntuforums.org/showthread.php?t=764907 but yesterday was one of the worst days of the year to do that. Since 8.04 was released yesterday there was a flood of help requests for people that were having trouble with 8.04 and I naturally didn't get any replies.

So yesterday afternoon I decided to go out and buy a different video card (ATI) and see if it worked any better, it wasn't worth spending hours fighting with this one. However, when I got it home, I got another rude surprise; it doesn't have a VGA connector on it.

Therefore I have decided to just leave everything the way it is right now while I learn how all this stuff works and stop wasting time flailing about, trying to work out little kinks right now. It does most of the things I need it to do right now. I can record ABC and CBS (I recorded Lost last night). We will just watch NBC in real-time on the old TV or online for the time being.

Thanks for the help! If I make any new discoveries, I will post them here.
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List of stations in Salt Lake City
PostPosted: Thu May 01, 2008 8:05 am Reply with quote
jsedwards
 
Joined: 18 Apr 2008
Posts: 11




First, in case these would be helpful for anyone, I put the two graphics that someone at KSL sent me of stations in the Salt Lake City area up on a website:

http://www.itsallgoodradio.com/Salt_Lake_City_OTA_Channel_Promo_Layout_p.png
http://www.itsallgoodradio.com/Salt_Lake_City_OTA_LPTV_and_LD_Channel_Promo_Layout_p.png

To update my progress: I went and bought an ATI X1550 card and replaced the nVidia GeForce 8300 with it. I couldn't get the xorg driver to work at all with the ATI card. I then installed the restricted Ubuntu driver and that worked, but Kaffeine seg faulted whenever I tried to watch any video. (With the nVidia card it just stuttered). I then removed the Ubuntu restricted driver and installed the driver I downloaded from the ATI site.

With it most of the videos I have tried played fine (it seg faulted on a couple of odd ones). The weird thing now is that I try to play the files from KTVX (ABC) I just get a black screen. With the same files that work fine in Kaffeine on my other machine. The files from KUTV (CBS) play fine. All of the others seem to have the same problems that I had when playing them on the other machine.

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PostPosted: Thu May 01, 2008 2:21 pm Reply with quote
waterhead
 
Joined: 24 Apr 2005
Posts: 299




When buying a new video card for use in Linux, ATI is a bad idea. Many of us have them left over from our Windows days, so we make do with what we have.

The nVidia 8300 is overkill for Linux, but it should have worked. Did you have XvMC setup? I'm not sure if this works for all applications, but here is setup info for MythTV:

http://www.mythtv.org/wiki/index.php/XvMC#Enabling_the_chipset_library

You need to see if you have this file, if not create it:
/etc/X11/XvMCConfig

The file should contain this line:
Code:
libXvMCNVIDIA_dynamic.so.1


Now setup your applications to use XvMC, and see if that improves the picture.

_________________
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Intel D875PBZ main board
Pentium4 3.06Ghz
1024GB RAM
nVidia 6600GT
pcHDTV HD-3000
Air2PC PCI
MythTV 0.21
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Some stations work okay and others don't
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