Scanning for Digital Stations Differences

[leatherneck]

Using HDHomeRun software scans and receives 156 digital and HD stations, when I scan throught GBPVR for "digital mapping" scans only 68 digital stations. In all cases I'm using the same HDTV tuners for scanning...very puzzel by this...can anyone explain why!

[wtg]

I believe it has something to do with the channel remapping hoops required for the BDA drivers. Basically it's being treated as an ATSC tuner instead of a true QAM tuner, I think because Microsoft hasn't created a QAM-compatible BDA interface yet. ATSC tuners only have 68 channels.

Something like that anyway. whurlston will chime in here and correct me if I'm wrong.

[whurlston]

I believe it has something to do with the channel remapping hoops required for the BDA drivers. Basically it's being treated as an ATSC tuner instead of a true QAM tuner, I think because Microsoft hasn't created a QAM-compatible BDA interface yet. ATSC tuners only have 68 channels.

Something like that anyway. whurlston will chime in here and correct me if I'm wrong.

Your not exactly wrong. The limit is due to MCE (and certain other PVR software) and not the BDA interface. MCE will not allow you to tune channels other than 2-69 (the ATSC spectrum) so Silicondust limited their BDA driver to that since it emulates ATSC for the QAM channels just as you described. GB-PVR does not have the 68 channel limitation but unfortunately they did not write a separate BDA driver for us. I would love it if they did but I understand not wanting to have two code branches. Not to mention the issues if someone tried to use the wrong driver with the wrong software.

I've considered reviving my HDHomeRun Recording Source plugin for instances just like this but I have not gotten around to it. It is actually possible to trick the HDHomeRun into tuning a different channel after the tune request has been sent to the BDA driver.

[leatherneck]

I’m not sure if I fully understand what you are saying here, but the problem is due to MCE limitation. So it seems that HDHomeRun has a better solution although we can not use it for GBPVR. HDHR software has a utility to reinstall/re-register Windows BDA components and HDHR BDA components but is not usable with GBPVR.

I don’t know how many installations of HDHR tuners using GBPVR, but this limitation sucks seeing all those stations and not able to record them.

I’m not technical enough to come up with a solution. But whurlston, I’ll help you any way I can if you have a solution to this problem.

[sub]

My understanding is that The HDHomeRun was one of the first Clear QAM devices to appear on the market. They wanted to the large pool of existing software that supported OTA ATSC devices with BDA drivers to automatically work with the HDHomeRun, so they created some fake BDA drivers that looked like an OTA ATSC device, and internally hid the fact that (for example) OTA channel 34 might map to QAM channel 110.

Application that use OTA ATSC devices typically scan physical channels 2-69. Somewhere there is a HDHomeRun mapping file that maps each of those 68 channels to a QAM physical channel. Obviously this wouldnt be able to map to every QAM frequency, but the majority of your QAM frequencies dont have any clear channels anyway, so wouldnt be usuable by your HDHomeRun anyway. In summary, with GB-PVR and the right HDHomeRUN mapping file setup you'll be able to receive every clear QAM channel you can receive through your HDHomeRun.

Make sense?

This is just messy stuff in my book. GB-PVR also supports devices that have real QAM support in their BDA drivers, like the Hauppauge HVR1600/1800/etc.

[JimF]

Unless you need all 156 channels, all you have to do is unselect the ones you don't need in the HDHomeRun Setup utility (channel editor tab). You can preview them also at that time to decide which ones to keep. Then, GB-PVR will only pick up the selected ones in it's scan.

[whurlston]

If you have any "audio only" stations, go ahead and disable them.