User talk:Brad606

From MythTV Official Wiki
Jump to: navigation, search

August 2009

I am attempting to build MythTV 0.21 from source, starting from a base installation of Knoppix 6.0.1's LiveCD. I am trying to follow the User Manual:Initial Installation instrections verbatim.

A few things have come up...

  • At least some of MythTV codebase appears to be compiled against QT3 rather than QT4. The evidence for this is attaempts to include files like <qsocket.h>, which exist in QT3 but not QT4. It is possible this is only for the UPNP section of the codebase.
    • Therefore, libqt3-mt-dev also appears to be a dependency.
    • Maybe that means libqt4-dev is not a dependnecy?
  • videoout_directfb.cpp appears to be a little too non-strict with data types for result codes from the DirectFB library. There is a DFBResult and a DirectResult, with the latter being more assocated with general freeing and allocating of resources. ERven though I'm sure the code worked as written (because "no error" is always an enum value of zero), for whatever reason my attempt to compile raised an error instead of a warning here.
    • I fixed this file such that it compiles, and might consider submitting it to the depot if I get my feet under me here a bit more.
  • fftw3 is listed as a dependency, but libfftw3-dev seems to be the name of the package, at least for Debian.
  • Can't find libmp4v2-dev -- best match was libmp4ff_dev.
  • Had to build libfame and libcdparanoia on my own, as libfame-dev and libcdparanoia0-dev weren't available for Debian.
  • Still can't find libraries transcode or libxvidcore4
  • Somehow, in the process of using apt-get install to satisfy all build dependencies, my server got uninstalled. This has a nasty side effect under Knoppix -- just after booting up the system shuts down.
    • To fix this, apt-get install xserver-xorg.
  • Added a couple of additional details about creating the MySQL database to the install page.
  • Need to add these details to install page:
    • Run mythtv-setup (before expecting mythbackend to work)
      • Set up the IP address of the backend server ( loopback for a single box configuration)
      • Set up a default directory for media files and create it (I used /mm/)
    • Setup input device
    • Setup program grammer
    • Map program grabber to video source or whatever
    • Scan for channels
  • Now, mythbackend should work nicely.

A couple weeks of successful DVR usage

I got my system all set up by mid-August, and started recording broadcasts and ripping, er, archiving all my DVDs. Things aren't perfect, but pretty darn amazing. This is some great software.

A few observed issues:

  • DVD ripping acts weird, at least in ISO mode. It asks you to pick which video segments to rip from DVD, yet appears to still just rip the entire disc wholesale.
  • Getting transcoding to work right was _really_ challenging. I kept getting a cryptic "No video information available!" error message from mythtranscode. Turns out, MythTV's data model is incredibly flexible for deciding what kind of transcoding is done for some sources, and there are profiles for this. I am using a "DVB Tuner card" (although it's actually ATSC), and the default recording profile wasn't set for this to work.
  • Transcoding is slower than I thought. About 15 fps for 720p MPEG-2 converted to MPEG-4, although I think that was only using 1 of my 2 CPU cores.

So, Knoppix isn't a general-purpose OS

I can't remember why I picked Knoppix for my first try at running Linux (well, okay, since Slackware in 1998). It's a great LiveCD, and KnoppMyth is probably a great LiveCD, too, but it's not easy to work with because of some tweaks it does. The final straw was realizing it disables SystemV-style init (/etc/rcX.d) in favor of iots knoppix-* scripts. This break almost every Debian package that contains a daemon.

I took this as an omen, and installed Kubuntu 9.04. That's just Ubuntu but with KDE instead of GNOME. Not that it matters, per se, but KDE use the QT library, which is what MythTV also uses.

Things are working much better, and this just feels like a better situation, although I'll admit I kindof like the simple, crisp, no-frills interface of LXDE.

Dropping frames in 720p MPEG-2

After the switch to Kubuntu, and a rebuild from source, I noticed I wasn't getting full-frame video all the time on HDTV broadcasts, and one CPU core was consistenly maxed out during playback. I have to believe this also was a problem under my Knoppix installation, but maybe there's jsut a little more running under the Kubuntu OS.

So I looked into whether or not I was using any kind of hardware acceleration. Hello, XvMC!