[mythtv] Help diagnosing HD channel recording problem

[Mark Paulus]

Bob Rakosky wrote:
> I've been trying to diagnose a problem that I've (always) been 
> experiencing with one of the high-def QAM channels I'm getting from my 
> cable provider.  I'm not convinced that the problem isn't with the 
> CableCo feed, but I'm starting to suspect that there is something in 
> Myth's recording logic that isn't quite right.
> 
> First, some basic info.  I'm using a HDHomeRun tuner connected to the 
> cable system.  Running SVN version 11820 (current as of this AM).  My 
> cable feed has one channel (the local CBS digital channel) that is the 
> only channel on one of the QAM transports, which is the one that is 
> causing me problems.  The following lines show the channel info for this 
> transport, using hdhomerun_config (aliased as the "hr" command below):
> 
> bobr at morris:~/tmp$ hr get /tuner0/status
> ch=qam256:699000000 ss=87 snq=90 seq=100 bps=38809216 pps=0
> bobr at morris:~/tmp$ hr streaminfo 0
> program 13: 0.0  filter="0x0000 0x0030 0x0800 0x0801"
> 
> This looks good, so far.  If I tune to this channel and set the filters, 
> fire up VLC and set the hdhomerun target for the tuner to the VLC's 
> network port, I get the video feed correctly.  Doing the same thing, but 
> using netcat and saving the stream to a file, the file will play back 
> correctly using Myth's internal player routines (via MythVideo).
> 
> However, setting up a recording for this channel in Myth, I get an MPEG 
> file that Myth won't play.  Neither will VLC (nor various other MPEG 
> players) that I've tried on both Linux and Windows boxes).  However (and 
> this is a little weird), I can load the same MPEG file into avidemux, 
> set avidemux to save an MPEG TS file, and save the video (without doing 
> anything else), and I get a resulting MPEG file that will play fine in 
> both VLC and MythVideo.
> 
> Attached is a snippet from my myth backend log with -v record,channel 
> for a 1-minute manual recording, as well as the output I got when I ran 
> the command "vlc -v 2 4080_20061125131500.mpg >vlcout1.txt 2>&1".
> 
> Note that the other high-def channels that I can get from the cable feed 
> work fine.  However, those channels are packaged differently in that 
> they are multiplexed on a couple of other QAM channels, as evidenced by 
> the following commands/output:
> 
> bobr at morris:~/tmp$ hr get /tuner1/status
> ch=qam256:729000000 ss=98 snq=70 seq=100 bps=38807712 pps=0
> bobr at morris:~/tmp$ hr streaminfo 1
> program 4: 25.2 WEEK-SD filter="0x0000 0x0032 0x0880 0x0881"
> program 3: 19.1 WHOI-DT filter="0x0000 0x0030 0x0800 0x0801"
> program 1: 25.1 WEEK-HD filter="0x0000 0x0031 0x0840 0x0841"
> 
> The CBS channel is the only "singleton" channel that I get.
> 
> I'm kind of at a loss as to how to further debug this problem (and not 
> particularly familiar with the MPEG data structures or spec).
> 
> Suggestions (or other assistance) would be nice.  If you want, I 
> will/can move this to the -Users list, but felt that it was more 
> appropriate for the -dev list.
> 
>  -- Bob
> 

I don't know if I can help, but perhaps you could try a couple of 
additional diagnostics that might help:
What does tcprobe show about the saved file?
what does TSReaderLite (http://www.coolstf.com/tsreader/) show about the 
saved file?

Perhaps some more info about your captured file would be helpful.

-- 
Mark Paulus
2424 Garden of the Gods Rd  | Phone:  v622-5578 / 719-535-5578
0419/117 - LEC Access ; D5-1010   | FAX:    719-535-1665
Colo Springs, CO  80919    | 1800PageMCI / 1406052
AIM : mgpaulus1    /  sametime : mark.paulus

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