[mythtv-users] Playback Profiles? WTF?!

Glen Hawksworth glenhawk at optusnet.com.au
Sat Mar 22 04:40:23 UTC 2008


After a long long day of working on the frontend I have come up with the
following:
      * reinstalling the frontend had minimal effect in the overall
        performance possible (except success moved from XvMC to
        libmpeg2, see more below)
      * using the 128MB ATI provided no benefit over the 64MB nVidia (it
        actually performed worse)
      * using the 256MB nVidia had minimal improvement over the 64MB
        nVidia
              * I think the 64MB is working well due to the 2GB of RAM
                and 256MB AGP aperture being used but not sure
      * the libmpeg2 decoder now provides the best over all results. My
        Playback Profile is as follows:
              * Priority 1: for >= 1920x1080 I use libmpeg2, xv-blit,
                softblend, no-OSD fade, no deinterlacing
              * Priority 2: for >= 0 I use libmpeg2, xv-blit, softblend,
                no-OSD fade, linear blend deinterlacing
      * at a screen resolution of 1920x1080 the 1920x1080 video stutters
        slightly so I tried a lower screen resolution. Problems:
              * my screen will not operate at any other 16:9 resolution,
                closest is 1280x960.
              * If I set the screen to 1280x960 the playback was fine
                and at the correct aspect ratio until I rebooted at
                which time the screen would be at 1280x960 but would
                scroll out to 1920x1080 or 1600x1200 (screen would move
                around with the mouse)
              * If I set the vitual mode (in xorg.conf) to 1280x960 then
                after a reboot I would be in true 1280x960 and the
                picture would be squashed with black bars top and
                bottom. I tried to adjust this within MythTV and got
                nowhere.
              * I found the setting in Appearance to dynamically change
                the resolution for different video streams. When
                dynamically changing the resolution to 1280x960 the
                picture retains its proper aspect ratio and does not
                scroll
      * I have set the screen to change to 1280x960 if it encounters
        1920x1080 video and remain at 1920x1080 for all other video

MY CONFUSING PROBLEMS:
      * Previously XvMC was the ONLY setting that resulted in acceptable
        video but it also caused a greyscale OSD that, in turn, caused
        stutter whenever it was on screen (for any HDTV or SDTV). NOW
        XvMC does nothing for me. All I get is terrible stutters for any
        combination of XvMC and I never see a grey OSD. Previously
        ffmpeg was the stuttery one and now it is ok. Previously
        linmpeg2 was stuttery, now it is what I am using. What could
        possibly have changed during the reinstallation of the frontend.
      * By my Playback Profile (and resolution settings), any 1920x1080
        video will be displayed at 1280x960 and interlaced. All other
        footage should be displayed at 1920x1080 with linear blend
        deinterlacing. However occasionally I get video appearing at a
        1280x960 resolution (which must mean it was broadcast in
        1920x1080) showing no interlacing problems but occasional
        stutters. Has this been broadcast in 1080p? I didn't think 1080p
        was being broadcast (in australia) yet. 
              * If it is 1080i why isn't it following my rule that says
                it should not be deinterlaced (to remove the stutter)?
              * Is it falling to Priority 2 and being deinterlaced with
                linear blend? How could I tell? Why would it not follow
                the rule for priority 1?
              * I tried another profile containing only the settings
                from Priority 1 but for all resolutions (>=0) and there
                was no change. The video in question still stuttered
                slightly and exhibited no visible interlacing (and is
                also still triggered the resolution change to 1280x960).

I am still baffled as to how I can go from a setup that "just-worked"
under 0.20 to a setup that required a day of fine tuning under 0.21
I am also exhaused from continually going back and forth between
watching video and playback profile setting. Exhausted by having to use
trial and error to identify the resolution of any given video:
      * turning on and off OSD fade to identify when a given profile
        rule is in effect
      * setting different screen resolutions (in the appearance
        settings) for different video resolutions so you can identify
        the video by the resolution that the screen takes
      * keeping my eyes peeled for interlacing in order to identify 1080
        HDTV
I looked and looked and could find no way of directly viewing the
resolution details of a given video with the exception of the following
(from Jason)...
        This should be simple to answer, but I can't remember or find
        it.
        'mplayer -identify <recording> -vc null -vo null' will work, but
        I
        know there's something nicer.
...which I don't understand

I am now giving Playback Profiles a rest... so I can reconfigure my
remote control after the reinstallation (I still have the lircrc file)
and then I want to figure out MythArchive... this will probably be my
last work on playback profiles for some time. ;-)


On Fri, 2008-03-21 at 13:42 +1100, Glen Hawksworth wrote:
> > Ok, so to check DMA you do as root:
> > 
> > hdparm /dev/hda
> > 
> Yeah found out about this but then found out that I am running UDMA
> 
> hdparm -i /dev/sda
> 
> > Replace hda with whatever drive your recordings are stored on. You won't 
> > really need to check for DMA on the CF card, since your recordings won't 
> > be on that one. There was another post earlier about resolution size. My 
> > TV has a resolution of 1366x768. I'm using a 1280x768 modeline in X. I 
> > also don't have a 1080p TV, so don't know whether processor usage would 
> > go up at that resolution.
> 
> OK I will try sacrificing some resolution (this box will eventually be
> connected to a 720 LCD when I get a new box for the 1080)
> 
> > But yes, ffmpeg does put most of the work on the processor.
> > My graphics card has 256MB of RAM I believe; it's an Nvidia FX5200, AGP. 
> > However, I don't think that you're going to need more RAM for HD 
> > decoding and displaying at an HD resolution.
> > 
> Yeah I plugged in the 256 that I have (that doesn't fit in the case) and
> I got more reliable performance. I am currently rebuilding with the 128
> ATI and will sacrifice resolution (could't get the ATI to do 1080) to
> see if 128 is enough.
> It is just so frustrating that all was acceptable in 0.20 and I can't
> emulate that with 0.21
> 
> > So what you're saying is you get stutter free HD with XVMC, and 
> > stuttering every 3-4 seconds with ffmpeg? Is your sql database on a 
> > separate drive from your recording? Some people have mentioned getting 
> > stuttering due to heavy sql activity.
> > 
> My SQL database is on the OS drive of my backend machine (I am pretty
> certain) and the recordings are on a separate 750GB drive (in the
> backend obviously) that I scored from work. The 750 is an IDE but
> running at ATA133 and all works fine watching TV from the backend (in
> the study)
> 
> > Hope you're making some progress.
> > Raphael
> 
> me too! I'll let you know the result soon.
> 
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> > 
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