Qam.ini Manager

[carpeVideo]

Does WinTV happen to tell you the frequency that it's using for physical channel 5?

WinTV sets up a database that should have the real frequency - I can't remember the details since I went back to my fusion card but its not too hard to figure out with sqlspy or something like that.

CV

[weisguy]

Does WinTV happen to tell you the frequency that it's using for physical channel 5?

I found a way to make it do this. Click the channel you'd like to tune and press the "Tune" button. WinTV is nice enough to show you the frequency it's tuning...



I added this manually to my qam.ini file, scanned it, and I'm locked in. I was able to find a reference listing this as NTSC Broadcast channel 5:

http://search.cpan.org/src/MLEHMANN/Vide...uencies.pm

Interestingly (and this is not a complaint in any way) that's not what your tool lists as channel 5, or even your old full qam files prior to your release of the tool.

I am guessing that a lot of people who are hunting rogue channels like this would benefit from an even more exhaustive list of scanning frequencies should your qam.ini manager tool want to list them as an option.

Thanks for your prompt response whurlston and the qam.ini tool. Your question prompted me to investigate exactly the right thing and, with all your other helpful posts in the past, figure out how to solve this one. I'll be watching Smallville in HD this week... or whenever I get to it. : - )

[whurlston]

Right you are. I was testing some alternate frequencies and forgot to set it back to the correct frequency table. It only affected lower channels and all my QAM channels are on 70+ so I didn't notice.

I updated the download in the first post. See if that one works better for you.

[weisguy]

Just wanted to confirm to you - the 'center frequencies' option picks up my rogue channel now. Thanks again.

[feilh]

So do you think this utility will work if you have installed TV Pack? Do I need to hack my registry with the 2250 or not?

[whurlston]

All this utility does is write a new qam.ini which is the list of frequencies GBPVR Config uses when scanning.

[zehd]

All this utility does is write a new qam.ini which is the list of frequencies GBPVR Config uses when scanning.

OK... so without this, when I run a new scan (and there is not scan.cache file) GB_PVR references something with a list of channels and frequencies. That list (where is it: a text file (qam.ini) , Registry entries?...) can be really big and cause for a long scan.

Your utility makes for a shorter list, with more accurate information (rather than general stabs in the dark) of freqs and ch numbers...

Is any of this right?

Sorry to others for the apparent hijacking. Once I know what this is all about (and whether I even want to use it ) I'll be writing a wiki page...

[whurlston]

The default qam.ini scans by channel number. A tuner's BDA drivers will then translate that channel number to a frequency using the Windows Tuning Spaces. The default tuning spaces uses for example a frequency of 507000 (507Mhz -- Windows tune requests are in Khz) for channel 71. The problem is that some tuners like the HDHomeRun and Hauppauge will add 1.75Mhz to the requested tuning frequency. Other tuners like Vistaview do not and so scanning by channel number works fine.

The QAM.ini Manager, in addition to limiting the number of channels in the scan, will create a qam.ini that will tune by frequency instead of channel number and remove the extra 1.75Mhz (Center channel settings) thereby allowing the tuner to tune the correct frequency. So for channel 71 (as my example above), GBPVR requests frequency 505250, the tuner automatically adds 1750, and tunes 507000.

There is also the issue of whether a cable system uses standard, HRC or IRC frequencies which I plan to address later.

[zehd]

The default qam.ini scans by channel number. A tuner's BDA drivers will then translate that channel number to a frequency using the Windows Tuning Spaces. The default tuning spaces uses for example a frequency of 507000 (507Mhz -- Windows tune requests are in Khz) for channel 71. The problem is that some tuners like the HDHomeRun and Hauppauge will add 1.75Mhz to the requested tuning frequency. Other tuners like Vistaview do not and so scanning by channel number works fine.

The QAM.ini Manager, in addition to limiting the number of channels in the scan, will create a qam.ini that will tune by frequency instead of channel number and remove the extra 1.75Mhz (Center channel settings) thereby allowing the tuner to tune the correct frequency. So for channel 71 (as my example above), GBPVR requests frequency 505250, the tuner automatically adds 1750, and tunes 507000.

There is also the issue of whether a cable system uses standard, HRC or IRC frequencies which I plan to address later.

With default GB-PVR has a list of channels from a QAM.ini

The BDA driver that is hardware specific will have added some registry keys that translate the channels to frequencies. (These came from a master db at Microsooft if I recall)

GB-PVR looks up the channel against the freguencies in regstry and then we tune and get a picture.

Your program gets in the middle so that you can use offsets?

Forgive me, I'll stoop asking stupid questions and get my hands dirty...

[whurlston]

With default GB-PVR has a list of channels from a QAM.ini

Correct.

The BDA driver that is hardware specific will have added some registry keys that translate the channels to frequencies. (These came from a master db at Microsooft if I recall)

Yes. I could make registry changes to override the frequencies so that you can always use the default qam.ini but I figured this was better.

GB-PVR looks up the channel against the freguencies in regstry and then we tune and get a picture.

GBPVR just sends the tune request from the mapping in the qam.ini. It's the tuner's bda driver that translates that as a channel number or frequency and do the lookup if its a channel number. The drivers will either always apply the offset when tuning or not at all. So when Windows reports that channel 71 is 507000 to the bda driver, the tuner may actually try to tune 508750 (507000 + 1750) and then doesn't lock onto the signal properly.

Your program gets in the middle so that you can use offsets?

My program just tells GBPVR wether to use channel numbers or frequencies for tuning requests. I just got tired of manually changing the qam.ini because I needed one setting for my Vistaview tuner and one for my HDHomeRuns. The default qam.ini worked fine for my Vistaview but the HDHomeRun kept applying the offset so I wrote this so I could easily switch out my qam.ini files as needed.