MythTV FAQ
) My mouse pointer disappears over the windows?
- This is desired behavior. The interface is meant for use with a remote control, or a keyboard.
) What's this 'strange error flushing buffer' mean?
- Nothing, really. It's just lame (the mp3 encoder) complaining for some obscure reason.
) The audio's _really_ out of sync, and it doesn't pause when I pause live TV?
- You need to mute the line-in, and set the mixer to record from the line in. The audio you're hearing is from the audio pass-through, enabled by the V4L driver, and not MythTV.
) I get an error when compiling about 'mkspecs'?
- You need to set QTDIR. On Debian, it should be /usr/share/qt On Mandrake, it should be /usr/lib/qt3
) I can't change the channel when watching TV?
- Something's wrong with your program database. Did filldata run with no major errors?
) I want to run the database on another machine?
- Ok, first, you'll need to edit the mc.sql script first to setup the proper permissions for the machine that'll be running mythtv and connecting to the database. Next, after you've followed all the directions and built all MythTV's programs, and after you've done a make install, but before you've run filldata, you need to edit the /usr/local/share/mythtv/mysql.txt file to it points to the server you're running the mysql on. If you want, you can copy that mysql.txt file to ~/.mythtv/. If it's in ~/.mythtv/ then it won't get copied over by another, future, 'make install'. Once that's all done, you should be all set, I think.
) Is it currenlty possible to have MythTV change the channel on my cable box, instead of my tuner? The reason I ask is because I have digtial cable, however I only have a analog WinTV tuner card in my PC.
- Yup, see here:
http://www.snowman.net/pipermail/mythtv-dev/2002-July/000020.html
Essentially, most of the code's there for it, it just needs someone that
actually wants the feature to finish it up.
) Which TVOUT card are people using?
- I'm using a Gainward Geforce4 Ti4200, but any card that has Xv support in
Xfree should work just fine.
) The "Tv Guide" function...does it only work in UK? I'm gonna be travelling, but not that far. :)
- No, the tv guide is xmltv (http://www.doc.ic.ac.uk/~epa98/work/apps/xmltv/). It current works in the US, Canada, UK, Germany, and Austria.
) I was also wondering if there is a specific reason a hardware encoder/decoder is not used?
- Well an encoder/decoder would be more efficient, but most of them are closed source requiring reverse engineering to build a driver. There is this one
(http://www.linuxtv.org/mpeg2/kfir.xml) if you're so inclined to integrate it into mythtv.
) First of all, I have gathered that you are using X11 and the Xvideo extension for your output. How do you control flipping the images of a video stream from one frame to the next such that they only get flipped on the vertical retrace (vsync pulse). As I understood it, this was not possible in X11/Xv. If you can't do this, then you must get horrible tearing of your displayed video streams.
- Actually, I only see very minor tearing when using a monitor as a display device, and that very rarely. On a TV as an output device, none at all. XvPutImage with a call to XSync immediately after seems to automatically sync up with the retrace. The video output code does make its best attempt to display frames at exactly the right times, which also helps.
) I have also gathered that you are using the Nuppel video format. I have not really looked much into this format myself, but does it store field information (i.e. interlaced streams) or is it progressive like MPEG1 and store frames? If it's progressive like MPEG1, how do you deal with the temporal issues of two fields, each being a different snapshot in time being combined together into a single frame? Do you get interlace artifacts or does Nuppel have some smoothing/blending/interpolating" algorithm to combine the two fields into a single frame?
-I've got code in there to deinterlace the image (grabbed the linear blend filter from mplayer), but that's only needed when displayed on a monitor --
the tv out (at least with nvidia's drivers) does the right thing and separates the frame into its fields for display.
end-------------------------------end
thanks,
Chris
) My mouse pointer disappears over the windows?
- This is desired behavior. The interface is meant for use with a remote control, or a keyboard.
) What's this 'strange error flushing buffer' mean?
- Nothing, really. It's just lame (the mp3 encoder) complaining for some obscure reason.
) The audio's _really_ out of sync, and it doesn't pause when I pause live TV?
- You need to mute the line-in, and set the mixer to record from the line in. The audio you're hearing is from the audio pass-through, enabled by the V4L driver, and not MythTV.
) I get an error when compiling about 'mkspecs'?
- You need to set QTDIR. On Debian, it should be /usr/share/qt On Mandrake, it should be /usr/lib/qt3
) I can't change the channel when watching TV?
- Something's wrong with your program database. Did filldata run with no major errors?
) I want to run the database on another machine?
- Ok, first, you'll need to edit the mc.sql script first to setup the proper permissions for the machine that'll be running mythtv and connecting to the database. Next, after you've followed all the directions and built all MythTV's programs, and after you've done a make install, but before you've run filldata, you need to edit the /usr/local/share/mythtv/mysql.txt file to it points to the server you're running the mysql on. If you want, you can copy that mysql.txt file to ~/.mythtv/. If it's in ~/.mythtv/ then it won't get copied over by another, future, 'make install'. Once that's all done, you should be all set, I think.
) Is it currenlty possible to have MythTV change the channel on my cable box, instead of my tuner? The reason I ask is because I have digtial cable, however I only have a analog WinTV tuner card in my PC.
- Yup, see here:
http://www.snowman.net/pipermail/mythtv-dev/2002-July/000020.html
Essentially, most of the code's there for it, it just needs someone that
actually wants the feature to finish it up.
) Which TVOUT card are people using?
- I'm using a Gainward Geforce4 Ti4200, but any card that has Xv support in
Xfree should work just fine.
) The "Tv Guide" function...does it only work in UK? I'm gonna be travelling, but not that far. :)
- No, the tv guide is xmltv (http://www.doc.ic.ac.uk/~epa98/work/apps/xmltv/). It current works in the US, Canada, UK, Germany, and Austria.
) I was also wondering if there is a specific reason a hardware encoder/decoder is not used?
- Well an encoder/decoder would be more efficient, but most of them are closed source requiring reverse engineering to build a driver. There is this one
(http://www.linuxtv.org/mpeg2/kfir.xml) if you're so inclined to integrate it into mythtv.
) First of all, I have gathered that you are using X11 and the Xvideo extension for your output. How do you control flipping the images of a video stream from one frame to the next such that they only get flipped on the vertical retrace (vsync pulse). As I understood it, this was not possible in X11/Xv. If you can't do this, then you must get horrible tearing of your displayed video streams.
- Actually, I only see very minor tearing when using a monitor as a display device, and that very rarely. On a TV as an output device, none at all. XvPutImage with a call to XSync immediately after seems to automatically sync up with the retrace. The video output code does make its best attempt to display frames at exactly the right times, which also helps.
) I have also gathered that you are using the Nuppel video format. I have not really looked much into this format myself, but does it store field information (i.e. interlaced streams) or is it progressive like MPEG1 and store frames? If it's progressive like MPEG1, how do you deal with the temporal issues of two fields, each being a different snapshot in time being combined together into a single frame? Do you get interlace artifacts or does Nuppel have some smoothing/blending/interpolating" algorithm to combine the two fields into a single frame?
-I've got code in there to deinterlace the image (grabbed the linear blend filter from mplayer), but that's only needed when displayed on a monitor --
the tv out (at least with nvidia's drivers) does the right thing and separates the frame into its fields for display.
end-------------------------------end
thanks,
Chris