23 Jun

Myth Works! All the Weather, All the Time

I found it.  And was subsequently able to record over 12 Gigs of The Weather Channel!  Yippie!  (That was just the channel I left it on for testing.)

Ok, here’s how it went down:  I finally swallowed my pride and dug through the mythtv-backend.log.  Well, actually, I opened up a terminal, switched to Myth, tried to watch Live TV, and then used “tail /var/log/mythtv/mythtv-backend.log” to see what just happened.  Much easier than “digging.”

Anyway, I got the following junk:

2008-06-20 12:52:10.501 TVRec(2): Changing from None to WatchingLiveTV
2008-06-20 12:52:10.531 TVRec(2): HW Tuner: 2->2
2008-06-20 12:52:10.797 SampleRate: Attempted to add a rate 32000 Hz, which is not in the list of allowed rates.
2008-06-20 12:52:12.846 AutoExpire: CalcParams(): Max required Free Space: 2.0 GB w/freq: 15 min
2008-06-20 12:52:13.248 NVR(/dev/video0): Won't work with the streaming interface, falling back
strange error flushing buffer ...
VIDIOCGMBUF:: Invalid argument
2008-06-20 12:52:53.280 TVRec(2): Changing from WatchingLiveTV to None
2008-06-20 12:52:53.310 Finished recording WGN News at Noon: channel 1004
2008-06-20 12:54:09.771 Expiring 0 MBytes for 1004 @ Fri Jun 20 12:00:00 2008 => WGN News at Noon

The sample rate thing didn’t seem too important as I knew where that setting was in the interface–however, I was strangely drawn to the bit about /dev/video0 (which is the location of my capture card).  So, apparently, it tries to access the card, fails, and drops back to the interface.

All of this time I was starting to form a picture that the Hauppauge PVR-350 was more than a little bit different than the average card.  I’ve seen quite a bit of stuff seeming to indicate why Kaffeine wouldn’t work for me, because the PVR-350 or the IVTV driver may not be Video4Linux (V4L) compatible.  Now, after searching on the above error, I find this thread where the user wilkinnh posted:

the “Unknown video codec” is what caught my attention, and i did a quick search and figured out that mythtv had automatically associated my capture card with the V4L (video4linux i believe…), but it’s actually an MPEG2 card with built-in hardware MPEG2 compression. so, i redid the mythtvsetup (the backend) and made sure when i selected my capture card that i selected it as MPEG2. once i did that and saved it, everything started working!

Suddenly, it was clear what was wrong!  Even though it said PVR-350 on the Capture Card Setup screen, I was still trying to use a V4L card!  I quickly go back in to setup and…but…wait a minute…what?

Where do you change this?  And then I discovered that I was missing some graphical clues that probably would have prevented this from happening in the first place.  The drop-down button was completely missing–making the dialog look like a static field!  I didn’t think that “field” was changeable–so I never even tried!!!


This picture is straight from the installation manual–I circled the part that I don’t have.  It’s not off the edge of the screen or anything.  It just isn’t there.  On my machine, under “Probed Info” it reported finding a PVR-350, leading me to believe that everything was hunky-dory.

Now I don’t feel so stupid.

Edit:  I forgot to mention that this also happened in KnoppixMyth, so there is something up with the Nvidia video card driver or the MythTV setup in general.  I did not try MythDora in this case, but I suspect the same problem would occur there too.

Next step is to get my second hard drive in use for storage groups.  Should be easy enough.  After that, I’ll hook the digital cable box back up and work on changing channels with the serial cable.

See you, Space Cowboy.

5 thoughts on “Myth Works! All the Weather, All the Time

  1. Good luck with the channel changing. I’m not sure if I ever got that to work correctly way back when.

    • There is actually an interface selection for “Serial to Motorola Cable Box” in the new versions. Let’s hope that it really is just *that* easy.

  2. Thanks for your post, I have been struggling for days with Mythtv without any luck until I found your post. Finally I can watch TV on the box and record stuff, thanks again, I completely missed that that screen had a drop down box.

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