Video/Audio Sync Problems-X800XL

[Skyeclad]

Help! I'm at my wits end and reconsidering the value equation of an HTPC. Scheduling and recording using GB-PVR has been a snap. Unfortunately, this all doesn't amount to much if I can't watch LiveTV or recordings without video/audio sync problems which I am having.

Here is my set-up:

XP SP2
A64 3200+
Asus A8n-e
2gb RAM
ATI X800XL
SB Live

I think I've tried every video/audio codec combination that I have with Overlay/VM7/VM9 and I still end up with video/audio sync problems when playing back HD. Typically the playback starts out fine and then I notice very small, almost imperceptible stutters and the audio starts to outpace the video. Then it becomes very noticeable that their is a sync issue. Pausing seems to reset the timing sometimes.

Here are the video codecs that I've used:

ATI MPEG
Intervideo
Cyberlink PDVD7
Nvidia Purevideo
Nero Video Decoder(purevideo)

The audio codecs are included for the video codecs above with the exception of AC3Filter.

Of all my codecs, Nero Video/AC3Filter/Overlay can be at times a stable combination but inevitably this too usually stutters and loses sync.

Is there anything else that I should be trying? To be honest, after what amounted to a smooth PVR installation, this issue has me frustrated because I don't know where the problem stems from.

[sub]

What device did you use to capture the video, or is it video you got from elsewhere?

[Skyeclad]

What device did you use to capture the video, or is it video you got from elsewhere?

I'm using an HDHomerun picking up OTA.

[sub]

It could be caused by the mux your using.

Have you tried playing the video back in another playback (like VLC) to check if the audio sync problem is there too? This will give you an indication whether the problem is occuring at recording time or playback time.

Sometimes the audio device drivers can also cause sync issues since the soundcard is often used for timing.

[Skyeclad]

I'm not entirely up on the term Mux. Are you referring to the HDHR device or software that allows you to view the stream? I know you can use VLC to view the HDHR stream so maybe that will tell me something.

I did try playing back recorded video using Nero and PDVD7 and I still notice some stutter but not nearly as often. I haven't used VLC.

I believe my audio drivers are the last ones they produced for the SB Live. I can try out the onboard audio though to rule this out though.

Do you use an X800xl? If so, what options are you using?

[sub]

I'm not entirely up on the term Mux. Are you referring to the HDHR device or software that allows you to view the stream?

When you record from a BDA device in GB-PVR it uses a mux to combine the audio/video streams together into a format that can be written to disk. The choice of mux filter (on the misc tab of the config app) can have an effective on the audio/video sync of the recording.

Do you use an X800xl?

No I dont.

[Skyeclad]

ok, so I should see what MUX filter GB-PVR is using. I can assume that it's set at some sort of default as I wouldn't have know what to do with the setting. OK, this gives me at least two things that I can do tonight. Thanks.

[sub]

Its worth noting that setting will list muxes you may not have installed. If one of these is selected, it'll try the others until it finds one.

You can check the muxes available on your machine by running MuxChecker.

[Skyeclad]

Muxchecker reported that I had cyberlink and ATIMux. I tried both along with the MSMuxer and the results were the same. I also changed my audio from my SB Live to the onboard audio and the Nforce drivers. That didn't have any effect either but....

I went back to the HDHR Manager and streamed video over to VLC and the AV sync was correct. So my thinking is that this is related to GB-PVR settings and I really need to find out what VLC uses by default. Of course, the preferences pages are voluminous and mention many codecs and settings but I can't figure out which ones are actually used. Any ideas?

Unfortunately, I was also playing with the HDHR installation and I ended up losing the connection to GB-PVR somehow. My channels show up but I can't scan for digital stations, it comes up with nothing.

[Skyeclad]

I loaded SageTV last night and used the same Cyberlink codec that I had used for GB-PVR. The result? Low CPU useage(30% or so) and no stuttering, halting, skipping or AV sync problems. So, for whatever reason, all my tweaking patching and cursing trying to get GB-PVR to work wasn't helpful because there's something different about these two programs which is the ultimate cause of the problem. Maybe the problem is with the MUXer but I'm not really sure what's different.