Jean,<br>
<br>
Here are some HDTV Performance tweaks I posted about a month ago:<br>
<br>
Things to check for best HDTV performance:<br>
<span class="q"><br>a) Right drivers for card with your kernel<br>b) Proper AGP bus speed and AGP interface driver in use<br>c) Proper user of openGL sync for retrace<br>d) Proper settings for deinterlace and, if used, xvmc
<br>e) Proper sound settings and handling of 5.1 sound and multiple streams<br>f) Real time scheduling of playback thread<br>g) Making sure disk or network speed is adequate<br>h) Nothing else sucking up CPU on the machine
<br><br>a) Right drivers for card with your kernel<br><br></span>Check /var/log/<xservername>.0.log. Excerpt from my<br>
/var/log/Xorg.0.log which shows nVidia driver version 7174:<br>
<br>
(II) LoadModule: "nvidia"<br>
(II) Loading /usr/X11R6/lib/modules/drivers
<div id="mb_19">/nvidia_drv.o<br> (II) Module nvidia: vendor="NVIDIA Corporation"<br>
compiled for 4.0.2, module version = 1.0.7174<br> Module class: XFree86 Video Driver<br><span class="q"><br>b) Proper AGP bus speed and AGP interface driver in use<br><br></span> [mythtv@mythtvbe
~]$ cat /proc/driver/nvidia/agp/status<br> Status: Enabled<br> Driver: AGPGART<br> AGP Rate: 8x<br> Fast Writes: Disabled<br> SBA: Enabled<br><span class="q">
<br>c) Proper user of openGL sync for retrace<br><br></span><span class="q"> Start mythfrontend with the "--verbose playback" option and redirect<br></span> output to a file. Check for Open GL Sync messages (SGI OpenGL)
<br><span class="q"> when a recording or live tv is played back.<br><br></span> mythfrontend.log:<br><br> 2005-04-25 22:29:36.515 Video timing method: SGI OpenGL<br><span class="q"><br>d) Proper settings for deinterlace and, if used, xvmc
<br><br></span><span class="q"> These are set via mythtv in the settings->tv->playback screens<br> (deinterlace on the first and xvmc on the fourth or fifth, IIRC). If<br> xvmc is set properly, the OSD will be black and white. If xvmc
<br> doesn't show up on the options screen, then it wasn't compiled into<br> the program. If xvmc is used, the "filters" field (which can also be<br> used to set deinterlace) isn't used. My personal opinion is that
<br> kernel deint appears to give a better picture (in terms of motion<br> artifacts) than the others (including BOB).<br><br></span><span class="q">e) Proper sound settings and handling of 5.1 sound and multiple streams
<br><br></span><span class="q"> I am using ALSA:digital for sound (via the Digital Sound HOWTO on <a href="http://mythtv.info">mythtv.info</a>) <br>
and I can confirm that it works since my DD receiver switches to digital mode.<br>
Not sure what</span> exactly to check here, but you can use "aplay -L" to get a listing<br> of the ALSA devices set up for your card / .asoundrc file. Testing<br> individual devices can be done with "aplay -D <device> <soundfile>".
<br><span class="q"><br>f) Real time scheduling of playback thread<br><br></span> Need to do a couple of things to get this working:<br><br> 1. chmod u+s mythfrontend<br> 2. Need to modify /etc/sudoers to add your mythtv user
<br> (use ALL option and NOPASSWORD; example in sudoers file)<br> 3. Start mythfrontend with sudo: "sudo mythfrontend &"<br><br> At this point the mythfrontend logs should say something like "using realtime priority"
<br><span class="q"><br>h) Nothing else sucking up CPU on the machine<br><br></span><span class="q"> Check using "top" and confirm that mythfrontend and X are the top two<br> items (X may be lower if XvMC is used). Remaining items should be
<br> substantially less (not sure how to define "substantial"...).<br>
<br>
I tried several different settings and the best performance I get is with the following:<br>
<br>
xorg.conf<br>
NvAGP = 3 (I couldn't get NVAGP to work, so AGPGART is what I'm using)<br>
mythtv<br>
OpenGL enabled (compiled from CVS)<br>
Kernel deinterlace<br>
libmpeg2 enabled<br>
realtime priority enabled<br>
video for timebase enabled<br>
extra audio buffer enabled<br>
xvmc *not* enabled<br>
<br>
On my AMD XP 3200+ system with an NVidia GF4 5500, using FC3 (kernel
2.6.10.770), Nvidia driver 7174, and mythtv v0.18 (compiled), frontend
and backend on one box, I get the following performance results:<br>
<br>
glxgears: 2962<br>
SDTV:<br>
Idle: 83%<br>
mythfrontend: 12%<br>
X: 2%<br>
FPS: 30.42 (no frames dropped)<br>
HDTV (720p):<br>
</span><span class="q"> Idle: 42%<br>
mythfrontend: 37%<br>
X: 14%<br>
FPS: 60.85 (no frames dropped)<br>
</span><span class="q">HDTV (1080i):<br>
</span><span class="q"> Idle: 12%<br>
mythfrontend: 61%<br>
X: 17%<br>
FPS: 30.42 (no frames dropped)<br>
</span><br>
<br>
Hope this helps!<br>
phlepper<span class="q"></span><span class="q"> </span></div>
-- <br>I hear and I forget. I see and I remember. I do and I understand. -- Confucius