Nu har jag grävt lite mer i det här och tar gärna emot synpunkter och kommentarer kring mitt problem.
Moderkortet jag har är ett Abit Fatal1ty F-I90HD med integrerad ATI Radeon X1250 grafikkrets, till vilken det tydligen inte finns några drivrutier som stödjer hårdvaruavkodning av MPEG2 (vilket erbjuds av kretsen)

. Uppspelningsinställningarna hade jag ställt till standard MPEG2-avkodning (myth använder då ffmpeg biblioteket) samt ingen deinterlacing (har även provat kernel). Än så länge kör jag på min gamla CRT-monitor med upplösningen 1280x1024.
När jag startade myth på följande sätt "mythfrontend -v playback,important" får jag reda på detta
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mythfrontend -v important,playback
X Error: BadDevice, invalid or uninitialized input device 169
Major opcode: 148
Minor opcode: 3
Resource id: 0x0
Failed to open device
X Error: BadDevice, invalid or uninitialized input device 169
Major opcode: 148
Minor opcode: 3
Resource id: 0x0
Failed to open device
2007-10-24 00:02:27.036 Using runtime prefix = /usr
2007-10-24 00:02:27.072 Gnome-Screensaver support enabled
2007-10-24 00:02: 27.072 DPMS is active.
2007-10-24 00:02:27.207 New DB connection, total: 1
2007-10-24 00:02:27.221 Connected to database 'mythconverg' at host: localhost
2007-10-24 00:02:27.222 Total desktop dim: 1280x1024, with 1 screen[s].
2007-10-24 00:02:27.225 Using screen 0, 1280x1024 at 0,0
2007-10-24 00:02:27.231 user: 1000 effective user: 1000 before privileged thread
2007-10-24 00:02:27.231 user: 1000 effective user: 1000 after privileged thread
2007-10-24 00:02:27.231 user: 1000 effective user: 1000 run_priv_thread
2007-10-24 00:02:27.238 Current Schema Version: 1160
2007-10-24 00:02:27.238 mythfrontend version: 0.20.20060828-3 www.mythtv.org
2007-10-24 00:02:27.238 Enabled verbose msgs: important playback
2007-10-24 00:02:27.804 New DB connection, total: 2
2007-10-24 00:02:28.015 max_width: 1280 max_height: 1024
2007-10-24 00:02: 28.131 Total desktop dim: 1280x1024, with 1 screen[s].
2007-10-24 00:02:39.395 RingBuf(/media/Media/TV/Inspelat/3_20071023143400.mpg): OpenFile(/media/Media/TV/Inspelat/3_20071023143400.mpg, 12)
2007-10-24 00:02:39.429 RingBuf(/media/Media/TV/Inspelat/3_20071023143400.mpg): CalcReadAheadThresh(4000 KB)
-> threshhold(146 KB) min read(32 KB) blk size(64 KB)
0: start_time: 0.036 duration: 326.466
1: start_time: 0.025 duration: 326.469
stream: start_time: 0.276 duration: 3627.524 bitrate=9701 kb/s
2007-10-24 00:02:39.628 AFD: Stream #0, has id 0x480 codec id MPEG2VIDEO, type Video, bitrate 12000000 at 0x0x9112300
2007-10-24 00:02:39.632 detectInterlace(Detect Scan, Interlaced Scan, 25, 576) ->Interlaced Scan
2007-10-24 00:02:39.632 AFD: Looking for decoder for MPEG2VIDEO
2007-10-24 00:02:39.632 AFD: Stream #1, has id 0x448 codec id MP2, type Audio, bitrate 384000 at 0x0x82c6850
2007-10-24 00:02:39.632 AFD: Looking for decoder for MP2
2007-10-24 00:02:39.655 RingBuf(/media/Media/TV/Inspelat/3_20071023143400.mpg): CalcReadAheadThresh(12384 KB)
-> threshhold(453 KB) min read(32 KB) blk size(256 KB)
2007-10-24 00:02:39.957 Mixer unable to find control Master
2007-10-24 00:02:39.957 Mixer unable to find control Master
2007-10-24 00:02:39.959 Dec: Trying to select track (w/lang)
2007-10-24 00:02:39.959 Dec: Selecting first track
2007-10-24 00:02:39.959 Dec: Selected track #1 in the Unknown language(0)
2007-10-24 00:02:39.959 Resyncing position map. posmapStarted = 0 livetv(0) watchingRec(0)
2007-10-24 00:02:40.225 Position map filled from DB to: 7558
2007-10-24 00:02:40.226 SyncPositionMap prerecorded, from DB: 7558 entries
2007-10-24 00:02:40.226 SyncPositionMap, new totframes: 90696, new length: 3627, posMap size: 7558
2007-10-24 00:02:40.226 AFD: Position map found
2007-10-24 00:02:40.226 AFD: Successfully opened decoder for file: "/media/Media/TV/Inspelat/3_20071023143400.mpg". novideo(0)
2007-10-24 00:02:40.268 VideoOutputXv: ctor
2007-10-24 00:02:40.268 Over/underscan. V: 0, H: 0, XOff: 0, YOff: 0
2007-10-24 00:02:40.268 Display Rect left: 0, top: 0, width: 1280, height: 1024, aspect: 1.33333
2007-10-24 00:02:40.268 Video Rect left: 0, top: 0, width: 720, height: 576, aspect: 1.33333
2007-10-24 00:02: 40.268 VideoOutputXv: Pixel dimensions: Screen 1280x1024, window 1280x1024
2007-10-24 00:02:40.269 VideoOutputXv: Estimated display dimensions: 313x230 mm Aspect: 1.36087
2007-10-24 00:02:40.269 VideoOutputXv: Estimated window dimensions: 313x230 mm Aspect: 1.36087
2007-10-24 00:02:40.269 VideoOutputXv: XvMCTex: Init failed
2007-10-24 00:02:40.270 VideoOutputXv: @ j=3 Looking for flag[s]: XvInputMask XvImageMask
2007-10-24 00:02:40.270 VideoOutputXv: No suitable XVideo port found
2007-10-24 00:02:40.270 VideoOutputXv Error: Could not find suitable XVideo surface.
2007-10-24 00:02:40.270 VideoOutputXv: Falling back to X shared memory video output.
*** May be slow ***
2007-10-24 00:02:40.270 VideoOutputXv: CreateShmImages(1): video_dim: 720x576
2007-10-24 00:02:40.271 Created data @0xa2d5d020->0xa2df4e22
...
2007-10-24 00:02:40.273 Created data @0xa1af5020->0xa1b8ce22
2007-10-24 00:02:40.299 Display Rect left: 0, top: 0, width: 1280, height: 1024, aspect: 1.33333
2007-10-24 00:02: 40.299 Video Rect left: 0, top: 0, width: 720, height: 576, aspect: 1.33333
2007-10-24 00:02:40.706 NVP: ClearAfterSeek(1)
2007-10-24 00:02:40.706 VideoOutputXv: ClearAfterSeek()
2007-10-24 00:02:40.706 TV: StartPlayer(): took 1181 ms to start player.
2007-10-24 00:02:40.706 VideoOutputXv: DiscardFrames(0)
2007-10-24 00:02:40.706 VideoBuffers::DiscardFrames(0): AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
2007-10-24 00:02:40.707 VideoBuffers::DiscardFrames(0): AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done
2007-10-24 00:02:40.707 VideoOutputXv: DiscardFrames() 3: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done()
2007-10-24 00:02:40.709 New DB connection, total: 3
2007-10-24 00:02:40.867 nVidiaVideoSync: Could not open device /dev/nvidia0, Enheten eller adressen finns inte
2007-10-24 00:02:40.867 DRMVideoSync: VBlank ioctl did not work, unimplemented in this driver?
2007-10-24 00:02:40.869 OpenGLVideoSync: GLX extensions: GLX_EXT_visual_info GLX_EXT_visual_rating GLX_EXT_import_context GLX_ARB_get_proc_address GLX_ARB_multisample
2007-10-24 00:02:40.869 OpenGLVideoSync: GLX Video Sync extension not present.
2007-10-24 00:02:40.869 RTCVideoSync: Could not set RTC frequency, Åtkomst nekas.
2007-10-24 00:02:40.869 Using audio as timebase
2007-10-24 00:02:40.870 Refresh rate: 16661, frame interval: 40000
2007-10-24 00:02:40.916 AFD: DoFastForward(3246 (1), do discard frames)
2007-10-24 00:02:40.916 Dec: DoFastForward(3246 (1), do discard frames)
2007-10-24 00:02: 40.916 AFD: SeekReset(3240, 6, do flush, do discard)
2007-10-24 00:02:40.916 AFD: SeekReset() flushing
2007-10-24 00:02:40.917 VideoOutputXv: DiscardFrames(1)
2007-10-24 00:02:40.917 VideoBuffers::DiscardFrames(1): UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
2007-10-24 00:02:40.917 VideoBuffers::DiscardFrames(): AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done()
2007-10-24 00:02:40.917 VideoBuffers::DiscardFrames(1): AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done
2007-10-24 00:02:40.917 VideoOutputXv: DiscardFrames() 3: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done()
2007-10-24 00:02:40.989 NVP: ClearAfterSeek(0)
2007-10-24 00:02:40.998 NVP: Waiting for prebuffer.. 0 AAAaAALAaAAAAAAAAAAAAAAAAAAAAAA
2007-10-24 00:02: 41.013 AFD: HandleGopStart: gopset not set, syncing positionMap
2007-10-24 00:02:41.013 Resyncing position map. posmapStarted = 1 livetv(0) watchingRec(0)
2007-10-24 00:02:41.013 AFD: HandleGopStart: Initial key frame distance: 12.
2007-10-24 00:02:41.376 NVP: Video is 3.34035 frames behind audio (too slow), dropping frame to catch up.
...
2007-10-24 00:02:42.519 NVP: Video is 3.06997 frames behind audio (too slow), dropping frame to catch up.
2007-10-24 00:02:42.743 AO: dropping back audio_buffer_unused
2007-10-24 00:02:42.767 NVP: Video is 3.10845 frames behind audio (too slow), dropping frame to catch up.
2007-10-24 00:02:45.035 VideoOutputXv Error:
***
* Your system is not capable of displaying the
* full framerate at 1280x1024 resolution. Frames
* will be skipped in order to keep the audio and
* video in sync.
'video_output' mean = '39682.09', std. dev. = '27728.71', fps = '25.20'
2007-10-24 00:02:45.968 NVP: Video is 3.3125 frames ahead of audio,
doubling video frame interval to slow down.
'video_output' mean = '39421.35', std. dev. = '23286.43 ', fps = '25.37'
2007-10-24 00:02:51.877 TV: StopStuff() -- begin
2007-10-24 00:02:51.877 TV: StopStuff(): stopping ring buffer[s]
2007-10-24 00:02:51.879 TV: StopStuff(): stopping player[s] (1/2)
2007-10-24 00:02:51.879 TV: StopStuff(): stopping player[s] (2/2)
2007-10-24 00:02:51.891 NVP: Exited decoder loop.
2007-10-24 00:02:51.910 VideoOutputXv: dtor
2007-10-24 00:02:51.910 VideoOutputXv: DiscardFrames(1)
2007-10-24 00:02:51.910 VideoBuffers::DiscardFrames(1): UUUUUUUUUuuALUUUUUUUUUUUUUUUUUU
2007-10-24 00:02:51.911 VideoBuffers::DiscardFrames(): AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done()
2007-10-24 00:02:51.911 VideoBuffers::DiscardFrames(1): AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done
2007-10-24 00:02:51.911 VideoOutputXv: DiscardFrames() 3: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done()
2007-10-24 00:02:51.911 VideoOutputXv: DiscardFrames(1)
2007-10-24 00:02:51.911 VideoBuffers::DiscardFrames(1): AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
2007-10-24 00:02:51.911 VideoBuffers::DiscardFrames(): AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done()
2007-10-24 00:02:51.911 VideoBuffers::DiscardFrames(1): AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done
2007-10-24 00:02:51.912 VideoOutputXv: DiscardFrames() 3: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done()
2007-10-24 00:02:52.000 TV: StopStuff() -- end
Myth skippar alltså frames på grund av att videon inte hinner avkodas i rätt hastighet. Fine, Myth hänger inte med i vald skärmupplösning av någon anledning. Så problemet kommer försvinna när jag ansluter HTPCn till TV'n, och när (om) det kommer drivrutier som kan dra nytta av hårdvaruavkodningen som finns i X1250-kretsen. Jag testade att sänka upplösningen till 1024x768 och det flöt på mycket jämnare, dock med väldigt hög processorbelastning

.
Det känns verkligen inte realistiskt att min C2D E4300 skall behöva svettas för att avkoda MPEG2 i 1024x768 med bibehållen framerate! VLC klarade uppspelningen galant i den högre upplösningen under exakt samma förutsättningar. Någon som har någon idé om varför det är så stor skilnad i uppspelningsprestanda?
Någon annan som kör myth med grafikkort från ATI? Hur är prestanda? Vilka inställningar kan man skruva på för att göra uppspelningen lättare för processorn?
Detta bådar ju inte gott inför ett framtida HDTV-köp....vill ju kunna se mina inspelningar i minst 720p utan problem utan att behöva överklocka processorn eller köpa ett löst grafikkort.