[devil's advocate]

For example, Fiber optic cable IN, Fiber optic cable OUT, and a dial that can vary the delay applied.

I think if cheap enough, it would be useful to have such a device to achieve synchronization of video and audio. I've always seen it where the video trails the audio. From what I understand certain network equipment imposes a delay to video but leaves audio as is, so a video delay WRT audio takes place.

Such a device shouldn't be too difficult to design and build. Probably no more than a second of delay should be enough to synch most signals.

What would it take? Receive port, memory, control circuitry for the delay, output port .....

 

[dbett]

Many AV receivers have this ability.

 

[Robert Spalding]

I talked to an engineer at my local CBS station once when we were seeing delay between audio and video (HDTV) and he said he actually delays the "video" not the audio on his end when this happens. Kinda interesting I thought.

 

[Kevin L]

I could probably count on one hand the amount of times this year I've seen a lack of sync between audio and video, and I have three HR-10s and one HDVR2 hooked up to my home theater. All my audio goes through my Onkyo receiver. Two component video feeds go through the receiver, too, but one of the HR10's component video goes direct to the TV. I don't see/hear any difference between the units. If I do get out of sync, rewinding a couple of times seems to allow it to resync.

If you're having that much of a problem, it's time to look at the a/v setup you have. As dbett said, many a/v receivers handle this, so perhaps that's what my Onkyo does. However, since one of my video feeds bypasses the receiver, and I don't, or rarely, have problems with any of them, I don't see how that would be the case.

BTW, I watch both OTA and by sat with the NY locals.

 

[danvines]

Yes, there are boxes that do this. Sorry, no link, but I've found them pretty easily w/ a google search. I've been considering one myself, since my Pioneer 1014 does not have that feature built in. I've put it off, though since just about the only time I seem to encounter it is on Discovery HD, and then only about 1/2 the time.

 

[chris_h]

I had the lip sync issue with Gilmore Girls last night. I think it has been many months since I have encountered a lip sync issue with a broadcast. I think it has to do with the fact that much of the equipment at the station was fried by a lightning strike and they are hobbling along on backups.

The solution I used last night was to listen to the sound from the SD tivo (downstairs, but usable in the great room) and look at the pic from the HD tivo in the greatroom. It takes a few minutes to get the sync right, but it is very doable. I realize this is not an option for most users.

The other solution I have used in the past is to delay the audio thru a DVD recorder, which provide 1.5 to 2 frames of delay. I realize that this option is also not available to most users.

I am still considering the DD540 device from www.felston.com (no affilation) but it still seems kinda pricey at $229. The advantage is that I do not have to rewire my home theater, which I would have to do if I bought an amp with built-in delay.

 

[mdryja]

AS noted above, many receivers have this feature. Many sound processors do as well. Although they're expensive (but check audiogon.com for great used deals -- I picked one up for half price), Lexicon audio processors have this functionality.

 

[wam319]

check out delayplayradio

 

[monkeyboy1010]

http://www.felston.com/buy.htm

 

[chris_h]

check out delayplayradio

wam319,

Do you work for them? Have you ever used this device? Since it provides up to 16 seconds of delay, with what looks like an analog slide switch, I doubt that you could get the granularity needed to fix lip-sync issues. I sure would be glad to be wrong about this. The cost is $140 instead of $229 like the felston, but it only does analog audio, whereas the felton DD540 does digital IIRC.

ps for those that want to check it out: www.delayplayradio.com

Their spec sheet is a little short on specs, IMHO.

 

[JimSpence]

The end user shouldn't have to resort to this approach to fix audio/video sync problems.
The stations/networks need to get their ducks in a row.

I have seen this problem quite a few times, mostly on network HD from DirecTV. Sometimes it is very obvious, but other times it is so subtle that it can be ignored.

 

[chris_h]

A friend of mine is interested in feedback on the delayplayradio device from anyone that has actually used it, whether for lip-sync issues or just delaying a radio broadcast (which is his use model). Thanks in advance.

 

[jor-el]

I just realized my receiver can do some level of delay. But how long? I suffer thru lip sync alright when it happens (just using TV speakers most of the time), but I wouldn't mind being able to listen to some sports events live using the radio announcer feed in place of the dreadful networks.

 

[digitalant]

Where is it that receivers have an a/v delay? I have the Onkyo TX-SR702 and I don't know where I would look for such a thing. It was a pricier receiver so I would hope it would have it if "many" receivers have it. Any help?

 

[Kevin L]

Where is it that receivers have an a/v delay? I have the Onkyo TX-SR702 and I don't know where I would look for such a thing. It was a pricier receiver so I would hope it would have it if "many" receivers have it. Any help?

Onkyo's are great receivers. Sorry to tell you, though, that the TX-SR702 does NOT have Adjustable Digital Delay (as Onkyo calls it).

I have it in mine, but I have the TX-SR800. I only think it's in the 800 and higher series. I can adjust from 0.0ms to +76.0ms, and can sync the surround speaker plus or minus to that, though I haven't had need to move it off the default of 0.0. Here's what the manual says about it:

3-4. Delay Sub-menu
This sub-menu gives you various ways to adjust the timing of the
audio output from the speakers to give certain soundfield effects or
to adjust for unwanted asynchronous video and audio tracks.
This sub-menu does not appear if “Direct” is selected as the listening
mode.
Setting Values Initial value
a. A/V Sync 0.0 ms to 74.0 ms 0.0 ms
Relative Delay
b. Center –4.0 ms to +6.0 ms 0.0 ms
c. Surr L/R –4.0 ms to +6.0 ms 0.0 ms
d. Surr Back –4.0 ms to +6.0 ms 0.0 ms

 

[DeDondeEs]

I have a Harmon Kardon AVR-235, it has a sound delay feature (never used it though). I picked it up for $300 from J&R Music world.

 

[TyroneShoes]

I talked to an engineer at my local CBS station once when we were seeing delay between audio and video (HDTV) and he said he actually delays the "video" not the audio on his end when this happens. Kinda interesting I thought.

Interesting in that either he didn't understand the question or didn't know the answer.

Delay between MPEG-encoded SDI video and AES audio, which is typically what is used at modern TV stations, is almost always audio leading video, first of all. MPEG video can actually slow down when the decoder is working very hard, which allows the audio to continue on at its normal rate. In decades as a professional broadcast engineer, I can't ever remember seeing video leading the audio. It could happen, but would probably be very rare and very brief.

Delay in video processing other than in MPEG is also common. Most video signals traverse at least a couple of, sometimes half a dozen or more, frame synchronizers on their way through the facility. Each of those can add as much as 2 frames of delay to the video, again making audio lead video. Good engineering technique uses devices to add delay back to the audio, recalibrating them. We have a few installed just before our STLs for this exact purpose, but those are probably not within most folks' budget.

"Delaying" video by itself, other than REALLY delaying it (by recording it and playing it back later) is just not done. There is no reason for it and no equipment that I have ever heard of for that purpose. Broadcasters regularly delay video timing or pulse signals so that sources can switch or transition cleanly, but we are talking about nanoseconds of delay. It takes 7 milliseconds of delay for human perception to perceive audio delay, and more like 1/5th of a second when detecting lipsync delay.

If a consumer has a continuing issue with one or more sources having a detectable non-changing lipsync problem, what I would recommend is a trip to your local Guitar Center, where you will find numerous devices from companies like Alesis that can dial in delay for $100 or so (analog...more for digital). Just look for stereo capability and the ability to pick off the delayed signal separately, rather than mixing it back in with the original (what these devices are usually used for).

 

[wam319]

chris_h,

I don't have one of the delayplayradio units yet, but looking it over. A friend sent me the link, and then I've been hearing the local sports DJ's talk about it as a gizmo to use to sync network sports broadcasts with local radio. Just thought it might be something to help.

A couple of years ago, I had searched and found some software for a PC that would provide an audio delay, but at the time it only had a 2 second range.

 

[chris_h]

chris_h,

I don't have one of the delayplayradio units yet, but looking it over. A friend sent me the link, and then I've been hearing the local sports DJ's talk about it as a gizmo to use to sync network sports broadcasts with local radio. Just thought it might be something to help.

A couple of years ago, I had searched and found some software for a PC that would provide an audio delay, but at the time it only had a 2 second range.

Thanks for the info. My friend actually went ahead and bought one of these. It is now living in my home theater on loan. I have not yet run into a show that has a lip-sync issue, so I have not tried it for that. I find myself in the odd position of hoping to have lip-sync issues...

If anyone can recommend a show to record from the D* HD-pack which often times has lip-sync issues, I am all ears. I also get HD OTA in the Sacramento DMA, and am open to suggestions for network shows to record that often have lip-sync issues.

 

[chris_h]

I have been using this unit in my home theater for a few weeks, and it seems to work pretty well. No remote control, analog-only, and the 16 second delay range makes it a little tough to "tune in" but overall pretty good.