On 1/28/06, Kevin Kuphal <[EMAIL PROTECTED]> wrote: > Jerry Rubinow wrote: > > On 1/28/06, Kevin Kuphal <[EMAIL PROTECTED]> wrote: > > > >> Jerry Rubinow wrote: > >> > >>> I'm running myth with separate front/back end computers. The frontend > >>> is a 2.8GHz P4 with 512MB ram, trying to display 720p HD, but I'm > >>> maxing out the CPU - myth ~65+%, X around 30+%. The video is at times > >>> choppy when there's a lot of stuff changing in the frame. What can I > >>> do to reduce CPU usage? > >>> > >>> Here's what I've done so far: > >>> -compiled myth with --enable-proc-opt (using SVN from less than a week > >>> ago) > >>> -using ratpoison for window manager > >>> -not using any deinterlacing > >>> > >>> Note: XvMC is not an option. > >>> > >>> I'm running FC4. > >>> > >>> mythfrontend -v playback reports that it's using Xvideo, format I420, > >>> using realtime priority, video timing method: RTC (glx vsync not > >>> supported in my driver). Then I get a lot of video ahead of audio > >>> dropping frames messages, and then a lot of audio ahead of video > >>> messages. > >>> > >>> /proc/meminfo says there's 100MB free while running myth, so I guess > >>> it's not swapping. > >>> > >>> What might be causing the high CPU? I've read about people with > >>> 2.4Ghz P4s not having a problem with HD, so it seems like there should > >>> be something I can do. Would compiling my own kernel help? With what > >>> options? Anything else I can try first? > >>> > >>> > >> Try using libmpeg2 for your playback. I'd suggest looking into > >> hyperthreading support in your kernel to see if it is enabled. I > >> believe this means using an SMP kernel. I'm not sure if that will make > >> a difference but it might. And lastly, your video card and drivers do > >> help alot. I've struggled with my choice of ATI on one of my frontends > >> and as I'm moving to HD, I'm biting the bullet and spending the $40 on > >> an Nvidia FX card and it will be one of the best $40 I've spent on my > >> system as it means HD playback on my 2.4ghz Celeron with XvMC. > >> > >> Kevin > >> > > > > Sorry, I left out that I'm using libmpeg2. Hyperthreading - hmm, > > unfortunately I just checked and my CPU doesn't support hyperthreading > > (it's a 533MHz bus 2.8GHz P4). I tried going the FX 5200 route, only > > to discover that I I can't achieve the transfer speeds I need over PCI > > (my motherboard only has two slots, both PCI). 1280x720x(24 or 32) > > bits, 30 frames a second (or 60, even worse) - PCI's max throughput is > > 600 to 700 Mbits/sec. I tried XvMC on the 5200 but it was always a > > bit glitchy. The onboard graphics is AGP, but now instead of being > > limited by bus speed, it's by CPU speed. Very frustrating, since it's > > soooo close to working properly. > > > > > Hmm. I'm about to buy an FX5500 PCI for use in my frontend. Are you > saying that you can't drive HD content to the PCI card because it is > PCI, not AGP? I'm using XvMC on my MX440 AGP and it works great with > Myth and the 7676 Nvidia drivers on the SVN. You might want to give > XvMC with that driver version another shot when 0.19 is released on your > FX5200. I've found it to be very solid. > > Kevin
When I was trying to do HD over the PCI FX5200, I consistently had slowness/skipped frames/stuttering. I eventually did some calculations, and 720p at 24bits and 30 frames per second is 632 Mbits/sec. I saw in the list archives that PCI's maximum transfer speed ranges between 600-700 Mbits/sec. However, I think 24 bit video is actually using 32 bips per pixels (alpha), and isn't HD refreshing at 60 frames/sec? So I must not be figuring something right, or else I wouldn't be getting anything approaching viewable, but I was actually getting something pretty close, so I'm not entirely sure what's going on. But in any case, it seems like at a minimum, it's close to PCI's capacity. As far as XvMC, I have no idea how the bandwidth of what's being pushed to the card for XvMC compares that of non-XvMC (although I would really like to know). I do know I had various problems with XvMC displaying correctly. Maybe due to bandwidth issues also, but I don't know. But I will give it another shot at some point before I throw in the towel on this computer and relegate it to an SD frontend for the tv upstairs. -Jerry _______________________________________________ mythtv-users mailing list [email protected] http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
