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Old 07-30-10, 07:15 PM   #1
kennelm
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Join Date: Nov 2008
Posts: 8
Default Another GT-240 Audio/video Issue

I am running MythTV on fedora 12, and I use the HDMI out on the GT-240 for both audio and video. When I playback content captured from my HDHR, everything is great. I get awesome video, and 5.1 surround sound. I am using VDPAU for this, and it seems to work no problem. My CPU is practically idling when I play back HD.

Recently, I picked up an HD-PVR, and I am capturing 720P from the STB and audio over RCA cables (S/PDIF works, but only on certain programming, so I had to go with analog sound). When I playback this H.264 content, the video was mostly watchable, but it was intermittently jerky. I enabled verbose logging in mythfrontend, and it turns out I was getting lots of dropped frames, in order to keep the audio and video in sync. I checked all my settings and, among many other things, I disabled the setting to upconvert stereo to 5.1. After that, the dropped frames went away, at least I thought, since the video became quite watchable. But, under scrutiny, I noticed a very slight sync issue with the audio and video. Here is what appears in the myth log now:

2010-07-30 19:18:42.078 NVP(3): Video is 3.04058 frames behind audio (too slow), dropping frame to catch up.
2010-07-30 19:18:42.178 NVP(3): Video is 3.02236 frames behind audio (too slow), dropping frame to catch up.
2010-07-30 19:18:42.278 NVP(3): Video is 3.01912 frames behind audio (too slow), dropping frame to catch up.
2010-07-30 19:18:42.378 NVP(3): Video is 3.00731 frames behind audio (too slow), dropping frame to catch up.
2010-07-30 19:18:42.498 NVP(3): Video is 3.11125 frames behind audio (too slow), dropping frame to catch up.
2010-07-30 19:18:42.578 NVP(3): Video is 3.0564 frames behind audio (too slow), dropping frame to catch up.
2010-07-30 19:18:42.698 NVP(3): Video is 3.12905 frames behind audio (too slow), dropping frame to catch up.
2010-07-30 19:18:42.778 NVP(3): Video is 3.07217 frames behind audio (too slow), dropping frame to catch up.
2010-07-30 19:18:42.878 NVP(3): Video is 3.00563 frames behind audio (too slow), dropping frame to catch up.
2010-07-30 19:18:42.998 NVP(3): Video is 3.08638 frames behind audio (too slow), dropping frame to catch up.

So, in the span of 1 second, my system dropped something like 30 frames. Does that even make sense?

If I go into mythtv and set the default audio to NULL, I get no sound, and the dropped frames disappear. I assume this means the audio is the problem?

Within mythtv settings, I get sound from both alsa: DEFAULT and alsa:HDMI. Don't think I tried all the choices, tho.

If I switch from VDPAU to SLIM or some other playback profile, I still get the dropped frames. I assume this means the issue is not VDPAU-related?

Here is my driver version, which I installed from the rpmfusion repos:

rpm -qa | grep nvidia
xorg-x11-drv-nvidia-libs-195.36.31-2.fc12.i686
xorg-x11-drv-nvidia-195.36.31-2.fc12.i686
kmod-nvidia-2.6.32.14-127.fc12.i686-195.36.24-1.fc12.3.i686
kmod-nvidia-195.36.31-1.fc12.1.i686
nvidia-xconfig-1.0-2.fc12.i686
kmod-nvidia-2.6.32.16-141.fc12.i686-195.36.31-1.fc12.1.i686
nvidia-settings-1.0-4.fc12.i686

This I got from atrpms:

rpm -qa | grep alsa
alsa-kmdl-2.6.32.14-127.fc12-1.0.23-84.fc12.i686
alsa-lib-devel-1.0.23-1.fc12.i686
alsa-kmdl-2.6.32.16-141.fc12-1.0.23-84.fc12.i686
alsa-driver-1.0.23-84.fc12.i686
report-plugin-localsave-0.14-1.fc12.i686
alsa-utils-1.0.22-1.fc12.i686
report-config-localsave-0.14-1.fc12.i686
alsa-lib-1.0.23-1.fc12.i686

This also from atrpms:

rpm -qa | grep mythtv
mythtv-0.23-235.fc12.i686

Sound card devices:

aplay -L
null
Discard all samples (playback) or generate zero samples (capture)
hdmi:CARD=NVidia
HDA NVidia, NVIDIA HDMI
HDMI Audio Output

aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: NVidia [HDA NVidia], device 3: NVIDIA HDMI [NVIDIA HDMI]
Subdevices: 0/1
Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 7: NVIDIA HDMI [NVIDIA HDMI]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 8: NVIDIA HDMI [NVIDIA HDMI]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 9: NVIDIA HDMI [NVIDIA HDMI]
Subdevices: 1/1
Subdevice #0: subdevice #0

I can post more of my log, but I didn't want to overload you guys with too much info until we at least try to frame this problem a little better.

Can anyone give me some pointers on how to address this?

Thanks!
Larry

Last edited by kennelm; 07-30-10 at 08:46 PM. Reason: edit
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