HDHomerun and native QAM channel mapping

[fiteclub]

I have had a slight problem with the new native QAM channel mapping feature which I originally posted on the Siliconedust support forum.Whurlston asked me to post my logs to this forum.

Briefly, the problem is that GBPVR does not find one of my clear QAM network channels (however it does find others on the same carrier frequency). Both the HDHomerun setup program and the old ATSC remapping method in GBPVR find it just fine.

Whurlston, the missing channel appears to be at frequency 669Mhz. When the HDHomerun setup scan finds it, it is assigned Tune 103-6. Other channels on the same frequency that ARE found by GBPVR is 103-2 and 103-8.

Let me know if you need any more info.

[whurlston]

It doesn't have valid PID numbers in the raw stream (0 for Video and no audio):

Code:

<service>
  <service_name>WLTX-HD</service_name>
  <TSID>4141</TSID>
  <service_ID>6</service_ID>
  <service_type>0</service_type>
  <pmt_PID>96</pmt_PID>
  <pcr_PID>0</pcr_PID>
  [color=Red][B]<video_PID>0</video_PID>[/B][/color]
  <major_channel_number>19</major_channel_number>
  <minor_channel_number>1</minor_channel_number>
</service>

When remapping, you probably had this info inserted into the stream by Silicondust.

Do you know the tuning string that it used with the remap option? You should be able to get the video and audio pids from that and manually create a tuning string for it. Or if you do a scan with the remap option and post the config.exe.log I can create it.

[fiteclub]

Out of curiosity, what causes this? Is it just carelessness or ignorance at Time Warner cable? Would this problem be happening to others that have built-in QAM tuners in their televisions? I would think that this could be a big problem. On the other hand, the HDHomerun setup app handled it just fine.

[whurlston]

Out of curiosity, what causes this? Is it just carelessness or ignorance at Time Warner cable?

Most likely. It's possible that the feed they get is missing the info but unlikely.

Would this problem be happening to others that have built-in QAM tuners in their televisions?

Possibly, depending on how the TV parses it's tuning information. There was someone else on the forum here who had the same issue with another tuner card, but I can't remember who.

I would think that this could be a big problem. On the other hand, the HDHomerun setup app handled it just fine.

The HDHomeRun software probably has additional logic to detect the video/audio streams on it's own without relying on the PSIP data. That type of programming is beyond my knowledge and abilities though so I'm just guessing on that.

[fiteclub]

OK, thanks for your help and input. I will try your suggestions as soon as I get a chance. BTW, do you know a good source for a primer on QAM nuts and bolts? I have a good technical background but am somewhat of a novice on digital broadcasting.

[whurlston]

I've been trying to find some of the sources I used when learning it but I can't find them. Here is a fairly decent book on the PSIP data though: http://books.google.com/books?id=0LktvPg...#PPA219,M1

What you would be particularly interested in (since it pertains to your problem) is stuff on VCT (Virtual channel table) and CVCT (Cable virtual channel table) that is part of the PSIP data.