Hello everybody

I have Mandrake Linux 9.0 installed on my AMD Duron @ 750, with 192MB RAM, 40GB hdd, Kworld Tv Tuner (Connexant/Philips bt878 chipset), and an ancient 8MB SIS 6326 AGP video card.

My problem is this... Although I have succesfully installed the tv tuner, and I can see good tv output in an xawtv window, when I switch to fullscreen, it starts to lose frames... I get about 8 fps in fullscreen

The thing is, when I configured xawtv, I had to set the video mode to grabdisplay, instead of overlay. In overlay mode, the tv output gets scambled and thrown around on the screen. The same thing happens with kwintv.

When I had my Mandrake 8.2, I had succesfully configured the tv tuner, and it worked great in fullscreen (with the same hardware). Also, Win98 works great with the tv tuner in fullscreen! However, it seems winxp has the same problem as the current linux.

I'm not sure who's to blame: The tv tuner or the video card... If I change the video card, will my problems be over?

Thanks in advance for your help!

...Anyone?

hmmmm, sounds like drivers for one or other is slow/crummy. It may be helped by using mplayer (it tends to be better optimized for a system).

Possible that mandrake didn't configure either of the cards properly (chose a bad driver for the graphics card for example). Or maybe it has superfluous junk running in the background chewing up resources.

Or, the newer version or <insert window manager> may be more bloated than the one in mandrake 8.1

HTH

Alex

P.S. A newer and/or better supported card will make things generally faster graphics wise though the speed of the processor will affect how quickly data can be shifted from tv tuner to the card (and any relevant processing inbetween). That's why excess programs running in the background could be causing the slowdown.

Aha... Thanks... Do you have any suggestions on how to test if my linux can display good quality fullscreen tv using another windowmanager? What should I use to reduce the amount of used resources?

When I normally run KDE (3.0), I have about 95Mb RAM free, and 1 or 2% CPU usage... When I start xawtv, there's not much change...

I didn't know mplayer could use the tvtuner... I'll give it a try... But how do I start it (with tv support)? If I rtfm, will I be able to configure it?

Thanks a lot!

Yeah if you RTFM you should be able to. I don't have a tv tuner but Im sure I read stuff about this in their documentation. You need to atleast compile it with the relevant option (rpm's etc. shlould have it compiled in but i strongly suggest rolling your own since the compile process optimizes the mplayer code with your machine very strongly (it'll detect what cpu your machine is and what extended CPU code it supports i.e. MMX, SSE etc.).

The thing with linux, is that its a bit too cunning with its handling of resources. It will cache stuff in the RAM and many programs will utilize what ever processing power there is left. When a higher priority program comes along, they'll give some more processing time back.

As for window managers, KDE and GNOME chew threw processing cycles so a more lightweight one (such as windowmanager or fluxbox or blackbox) might aid a bit. They also tend to be a little less heavy on the graphics card. If you love KDE/GNOME then you may want to turn off the bells and whistles that might be runnning (such as weird flashing menus etc.).

Your RAM and processor should be fine, the graphics card may be a bit weedy but it might be able to handle things fine. Atleast it isn't having to decrypt video like with DVDs.

HTH

Alex

P.S. make sure that there are no progs you don't need running in the background and recompiling the kernel may gain a bit of speed for you machine.

full screen playback is 640x480 on most tv cards, if your playing this back at your desktop full screen then the picture is degraded. Mandrake 9.0 should have a xawtv icon on your desktop that is already config'd to play only @ 640x480 even when you hit "F" to go to full screen.

I've been running xawtv and mythtv on my mandrake system for about 6 months with an ati tv wonder which is a philips tuner so i'm guessing your card is going to perform similar.

The thing is that xawtv doesn't automatically switch to 640x480 when playing in fullscreen. I know that in Windows 98, the tv tuner software changes the resolution. But in XP or linux it doesn't do that automatically.

How do I force xawtv to run in 640x480 when in fullscreen? And preferably without restarting my Xserver?

The icon on my desktop doesn't do that... Is there a switch or something?

Thanks for the help

hehe.. there's the catch.. my system that did that has been compiling gentoo for 2 days now and my mandrake system is gone, so I don't have the working example to show you.
However I know that I had my tvcard in when I installed Mandrake and the xawtv icon it put on my desktop ran better than the normal kde --> multimedia --> video --> xawtv way.
I believe it had some /dev/video0 and some variables in the run command. However I honestly don't remember what.

My xawtv icon executes the following:

xawtv -c /dev/v4l/video0

There's not much optimisation going on...
However I've done some digging on mplayer. And it supports tv, but I'm not sure what -channel means. I was able to catch a channel with the -freq= flag, but it was in overlay mode and didn't display properly... I'll keep searching.
In the mean time I found out I could cycle through my X resolutions and set the display in a lower res mode, where I can see tv output in 'fullscreen'.

All I have to do now is install lirc...

I managed to switch resolutions, but now, in 512x348 (or something like that) I still get some poor performance. It seems that it's unable to refresh the image as fast as I need... It also has a flickering effec (but not that serious).

The most serious problem is a deinterlace effect that appears on moving images. This makes scroling text unreadable...
Does xawtv have a filter to correct this? Or is there a program I can use? (I know mplayer can do this, but I still don't know how to set a channel...)

I'm wondering... Does the tv tuner write its output directly into the video RAM, or does it copy it to the system ram, and the system writes to the video ram? If it's the latter, I'm not surprised it's slow...

It would be the latter, I very much doubt that the tuner writes directly to the hard ware. That is the aim of the DRI project I think. At the moment, video output starts from the program you using -> XFree -> (kernel?)-> driver provided by XFree-> video card. The DRI project is making drivers which go straight to the video card without faffing around with XFree and kernel stuff.

As you may have guessed, Im not too up to scratch on the internal workings

For the flickering, does xawtv allow you to drop frames like mplayer does? that may help with the flickering.

HTH

Alex

I have no idea if xawtv can drop frames... It doesn't say a thing in its man page...

I wasn't sure if it could write directly to video ram... It would certainly be faster if it could...

Thanks for the help