[mythtv-users] Can't get a good Playback Profile

[MythTV]

In the previous incarnation of my MythTV install, I used the generic  
"nv" X11 driver to watch my HD shows.  The newest version of MythTV  
shows a blank screen if the "nv" X11 driver is used; thus, I have to  
use the proprietary driver "nvidia", which is suppose to be better...

Well, I can't get my Playback Profiles to work without artifacts,  
dropped frames, loss of sound, etc.  "Mac Hardware acceleration"  
Decoder with "2" Max CPUs work okay for very slow motion, but a pan,  
or sports, or even the actor's eyes blinking are beyond the capacity  
for my system now.  "libmpeg2" Decoder with "quartz-blit" Video  
Render sometimes works too on certain types of reality TV.  But, I  
can't find any setting that is near as decent as that generic "nv"  
X11 driver I use to use.

I have read the Playback Profiles page multiple times:
http://mythtv.org/wiki/index.php/Playback_profiles

The idea behind Playback Profiles seems cool but it also assumes that  
you know the resolution of your shows.  How do I find out what the  
resolutions are on my shows?

Because you can have 5 or more profiles, I don't know which profile  
is selected when playback is occurring.  Is this mentioned in /var/ 
log/mythtv/mythfrontend.log?  How do I know which profile setting is  
being use?

I have created a Test profile that has only one setting.  Thus, I  
assume that that's the setting being used.  Is this a correct  
assumption?  What happens when the setting doesn't work or my  
hardware doesn't support the setting?

There are probably a hundred different settings I can try thus time  
consuming and tedious.  This is standard technology; there has got to  
be a more scientific way to know what profile setting to use.  Is  
there another location to go to learn more about configuring Playback  
Profiles?

Rob
My configuration is:
MythTV version: 0.21.20080304-1 18722
Ubuntu 8.10, kernel version: 2.6.27-9-generic
CPU: Intel Pentium 4 CPU 3.2GHz Socket 775 800 FSB w/Hyper Threading  
Technology
Memory: 1Gig DDR 333 Memory 180 Pin
Motherboard: ASRock 775i65G Mother Board
Optical Drive: LG 18X DVD RW + Dual Layer
Hard Drive: 1 Western Digital 250 Gig HD contains the OS and 1  
Western Digital 1 TB 7200 RPM Cache Serial ATA contains the video data
Video onboard: Integrated SiS Ultra256 2D/3D Graphics
Video card: Micro-star International (MSI) AGP GeForce FX5200- 
TD128LF, 8X, 128M, DDR1, D-Sub, DVI-D, TV-out
Audio onboard: AUDIO ADI AD1888 6-channel audio CODEC
Audio card: Riviera C-Media CMI 8738 (Connected to my entertainment  
center via the optical cable)
Network Card: Onboard 10/100 Network Card
Tuner cards: 2 pcHDTV HD-5500