I have a new Sony A/V Receiver STR-DG910 and TV KDL-52W4100. One of the things that caught my eye on the receiver spec sheet was...

Advanced A/V Sync Special Digital Signal Processing allows for lip sync delay to adjust to match the refresh rates
of today’s advanced flat panel televisions and microdisplays.

My older setup has always had a problem with the HD video lagging behind the audio. I was hoping that somehow, through the HDMI connection, the TV and the receiver would automatically sync the audio and video.

Now that I've got it running, it appears that the only way to adjust A/V Sync is a manual delay setting in the receiver menu (the same as my older system).

Am I missing something? What's so "advanced" about that? Any suggestions?

I'm not sure what answer you're expecting. Most receivers didn't use to have an option to delay the audio to makeup for video processing delay, newer ones do, and it can be a useful feature. Setting it manually versus automatic detection shouldn't be too much of a problem, after all, your video processing delay isn't bound to change that drastically over time so a manual setting does fine. That, and there is no way to do an automatic detection for such a thing, as there is no feedback loop for the final result to be fed back into the receiver to come up with a delay figure.
Just in case, this is a entirely different setting than individual speaker delays. I doubt this is what you're talking about, but figured i'd mention it just incase.

I'm not sure what answer you're expecting. Most receivers didn't use to have an option to delay the audio to makeup for video processing delay, newer ones do, and it can be a useful feature. Setting it manually versus automatic detection shouldn't be too much of a problem, after all, your video processing delay isn't bound to change that drastically over time so a manual setting does fine. That, and there is no way to do an automatic detection for such a thing, as there is no feedback loop for the final result to be fed back into the receiver to come up with a delay figure.
Just in case, this is a entirely different setting than individual speaker delays. I doubt this is what you're talking about, but figured i'd mention it just incase.

Actually I was hoping that maybe I missed something in the setup and somebody here could set me straight. I somewhere got the idea that A/V sync meant that the HDTV was sending a delay signal to the Amp through the HDMI cable, which then delayed the audio by the correct amount.

As for the not changing over time, it's odd, but I certainly notice the sync problem a lot sometimes, and not so much at others. Maybe some of that is with different cable HD sources, but even during one BD movie, I think I see it change. I did try "calibrating" it with DVE to get the "pop" and "flash" together, but with the audio delay set to max (200 ms), it wasn't quite enough.

Thanks for the explanation.

That, and there is no way to do an automatic detection for such a thing, as there is no feedback loop for the final result to be fed back into the receiver to come up with a delay figure.

It's probably implemented via HDMI and it's inherent two-way protocol.

Clearly something makes it work. I don't think the OP is asking people here to debate that. I think the question surrounds its efficacy.

It's probably implemented via HDMI and it's inherent two-way protocol.

Clearly something makes it work. I don't think the OP is asking people here to debate that. I think the question surrounds its efficacy.
Yes, a "manual" setting makes it work, as stated above...
As the manual states:
"Lets you delay the output of audio to minimize the time gap between audio output and visual display. You can adjust from 0 (0 ms) to 20 (200 ms) in 1 (10 ms) steps."
And, yes, systems can be made to make use of hdmi's ability to talk back and forth, but this would only work if the two used the same protocol, which would require a standard between all hmdi devices. And i have yet to hear of any hdmi av sync delay protocol (though, i admit this does not mean any does not exist). Though, i did hear something about hdmi 1.3 supposedly supporting some sort of av sync feature, but i have not heard of it since then. Not to mention, from sony's own manual, it is obvious they have only done a manual implementation.

That, and there is no way to do an automatic detection for such a thing, as there is no feedback loop for the final result to be fed back into the receiver to come up with a delay figure.

While what you say would be totally true of analog signals without special synchying overhead such as NTSC etc., this is digital and so a completely different set of rules applies.

Both audio and video are clocked digital as HDMI data. Data processing algorithms require a known number of cpu cycles to do their work. The processor can know how many cycles it delayed audio and video data then recompile the processed data at the end of the chain delaying output of the data finished being processed first until the other set of data is ready. Thus we have automatic resynching feature already built into HDMI V1.3 and up.

It's all a numbers game in the digital world. The fact that a piece of audio data is clocked with some other piece of video data as it is read from it's source indicates these two go together. All we have to do is remember where each piece came from then what we are doing to it and respond intelligently. It's what computers are good at.

While what you say would be totally true of analog signals without special synchying overhead such as NTSC etc., this is digital and so a completely different set of rules applies.

Both audio and video are clocked digital as HDMI data. Data processing algorithms require a known number of cpu cycles to do their work. The processor can know how many cycles it delayed audio and video data then recompile the processed data at the end of the chain delaying output of the data finished being processed first until the other set of data is ready. Thus we have automatic resynching feature already built into HDMI V1.3 and up.

It's all a numbers game in the digital world. The fact that a piece of audio data is clocked with some other piece of video data as it is read from it's source indicates these two go together. All we have to do is remember where each piece came from then what we are doing to it and respond intelligently. It's what computers are good at.
I see, though just because things are digital does not mean they won't experience delay. But it seems, after doing a bit of quick research, that since hdmi transmits the audio with the video, in packets that have reconstruction data with them, it may be possible to reprocess the data to remove the delay (which also prevents jitter from being a problem).
So, in this case, i wonder if the op's problem of extensive delay is due to him perhaps not having a complete hdmi 1.3 compatible data chain to remove the delay?

I see, though just because things are digital does not mean they won't experience delay. But it seems, after doing a bit of quick research, that since hdmi transmits the audio with the video, in packets that have reconstruction data with them, it may be possible to reprocess the data to remove the delay (which also prevents jitter from being a problem).

Yes.

So, in this case, i wonder if the op's problem of extensive delay is due to him perhaps not having a complete hdmi 1.3 compatible data chain to remove the delay?

You guys are talking way above me on this, but I appreciate the learning. So how do I know if I have a 1.3 compatible data chain?

You guys are talking way above me on this, but I appreciate the learning. So how do I know if I have a 1.3 compatible data chain?
Basically, i'm assuming you're running the hdmi from the source, to the receiver, to the display, correct? If i understand everything correctly, all devices must be made for the 1.3(or later) versions of hdmi, for them to use 1.3 features (which includes the automatic av syncing). However, if your source is not 1.3 and your receiver receives an hdmi data stream, and is 1.3 it may then take the data and transmit it to your tv using 1.3 (assuming your tv is 1.3), but this won't help it recover from any delay from the source to the receiver, and vice versa if your tv is not 1.3 but the rest is.

Basically, i'm assuming you're running the hdmi from the source, to the receiver, to the display, correct?

Yes, I have a total of three connecting cables. One HDMI from the Blu-ray to the Receiver, one HDMI from the HD Set-top box to the receiver, and one from the receiver to the HDTV.

I didn't see anything stating that any of these are HDMI 1.3 specs, but they are all brand new models, so I would expect they are the latest.