Sync issue with "some" HD recordings?

[Anthony]

OK, new problem recording HD material with my HVR-1600. I recorded a show a few nights ago ("Big Bang Theory" on CBS) in HD. Show recorded fine, no errors (sorry, I don't have the logs from that recording).

However, when I play back the video, the audio is significantly out-of-sync with the video. I get the same results whether I play the file on my computer, or using my network media player. So, I don't think it's a codec or player issue. It's obviously recorded that way.

I can record other HD material with the same bitrates and specifications and they turn out fine. But, this is the second time I have recorded this show and had sync issues.

I have had sync issues like this in the past (on different channels), but didn't make the connection till now.

I'm currently using the Cyberlink MUX, but the last out-of-sync recording was with the DVR-MS MUX.

Any ideas what is causing this and how I can fix it?

Thanks,

Anthony

[sub]

Pretty much the only thing you can do that would have any impact on this is trying other muxes. From what I've read though, it sounds like the dvr-ms works best HD material.

The mux is responsible for generating the playback timing info. GB-PVR has no control other than selecting the mux that is used..

[zed]

FWIW, I've noticed that some shows in HD seem to be slightly out of sync 'live' so the problem may not be on your end. I see it when watching a show directly off the cable...not all of them, just every now and then. I don't know if they come that way from the network or lose sync somewhere in between. I blamed the cable box but it could be something else.

[Anthony]

Sub,

I've tried both the Cyberlink and DVR-MS MUX's and get the same sync issue with each.

Zed,

Hmm.. Could be. I'm pretty sure I've recorded other high def shows on the same channel that were in perfect sync. But this is the second time I've recorded this one show and had the sync issue. So, maybe it is coming in that way. I haven't been around to try watching it "live" to see if the problem is still there.

Aren't there some kind of timecodes or something in the incoming audio/video that should keep them in sync?

Anthony

[Anthony]

More testing...

It appears anything I record on the CBS digital station ends up out of sync.

I tried watching the station "live", but I'm not getting ANY audio on any of the digital stations? I do get audio on the analog stations.

Anthony

[sub]

Sorry, I dont really have any suggestion for you other than the comments I've already made above. GB-PVR really has no say in the timing info stored by the mux.

I tried watching the station "live", but I'm not getting ANY audio on any of the digital stations?

This is most likely because your audio decoder isnt AC3 capable.

[Anthony]

> This is most likely because your
> audio decoder isnt AC3 capable.

Hmm.. I "do" get audio in the preview on the "Map digital channels to EPG channels" screen of the configuration utility? Unfortunately, it's too small of an image to see if the audio and video are in sync.

This HD stuff is so frustrating. My local NBC channel looks fine Live, but ends up garbled and unwatchable when recorded. My local CBS channel records fine, but the audio/video is out of sync. I've spent a few hundred dollars on new tuners, amplifiers, and splitters, but it's getting to the point it's practically useless. It makes a person want to scream!

I haven't had much luck with the HVR-1600's, and I couldn't get the HDHomeRun to work at all. Are there better QAM tuners out there that will work with GBPVR?

Anthony

[sub]

I haven't had much luck with the HVR-1600's, and I couldn't get the HDHomeRun to work at all. Are there better QAM tuners out there that will work with GBPVR?

I doubt you'll find much difference with other QAM capable tuners. When it comes to digital devices they all produce pretty much identical results. They pass the raw received data out through either the decoders (when watching live tv) or through the mux (when recording). The way the broadcaster encodes the data prior to transmission, combined with the decoders and the mux you're using, will probably produce the same result regardless of which QAM device you're using.

You could see if the ATI mux produces any better results for you. Alternatively, the next release also supports the Hauppauge MainConcept mux.

[sub]

If you have access to a web server and are able to record a raw transport of about 250MB of NBC, I'm happy to download it an take a look at this corruption you get to see if I can provide any more info.

[Anthony]

> If you have access to a web server and are able to record a raw
> transport of about 250MB of NBC, I'm happy to download it and
> take a look at this corruption

I'd be happy to record and upload a file for you. How exactly would I record a "raw transport"? Just do a normal record in GBPVR?

Does it need to be 250MB in size? It might take me a bit to figure out how long of a recording that would be on that channel.

> When it comes to digital devices they all produce
> pretty much identical results.

That's what I figured, but I've had nothing but trouble with these computer tuners. My regular TV has no problem locking onto any of these same channels, perfect sync, perfect picture, etc.

> You could see if the ATI mux produces any better results for you.

Any idea where I could download that?

> the next release also supports the Hauppauge MainConcept mux.

Interesting. I look forward to trying it out.

Thanks,

Anthony