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Lip sync?
Posted: Sun Sep 17, 2006 6:44 am
by j090733
Jerry Keller writes:
I am using a samsung SIR-T451 OTA tuner. This unit is connected to a Sony HDTV ready Monitor via a DVI digital connection. But I use the optical audio output (Toss-link) from the Samsung into my home theater receiver so that I will have surround sound to accompany the HDTV picture. The problem with this is, a slight error in lip sync. The sound is not in sync with the picture. Is there any solution to this problem?
Thank you
Jerry
Posted: Mon Sep 18, 2006 8:07 am
by Richard
This has become a general problem with our new digital displays because of the time it takes to process the video; a lot more things have to happen between where the signal comes in and when it finally makes it to the display device. The audio may have to be delayed to make up for that for those who notice.
It is possible to have a bigger problem when not using the TV speakers because they compensate for this in the TV circuits but few HT folks are going to use TV speakers.
There are scalers out there that offer a digital input along with the video so you can add delay. I have not checked but this could be easily implemented in the A/V receiver.
For the most part people are not noticing.
There is also the occasion where the problem is related to a specific channel or form of delivery; call the provider or broadcaster.
more on lip sync problem
Posted: Mon Sep 18, 2006 1:29 pm
by j090733
Jerry Keller writes:
Richard,
Thank you for your rapid and lucid reply. I am a retired Television technical director and I really do notice the lip sync problem. As I recall, from days past, audio delay lines are going to be a relatively expensive cure. It would be nice to have them built in to the HDTV's or the home theater systems. If we were dealing with film and a separate audio track, I would say the audio is ahead of the video by about one frame of 35mm film.
Thanks again.
Jerry
Yes, lip sync is becoming a problem
Posted: Wed Nov 15, 2006 11:54 am
by jcrobso
I installed a very nice 5300ansi lumen upscalling video projector a couple of years ago for a Church. The unit dose a grate job of upscalling the video, BUT it introduces a 50ms video delay in the process. I had to add a 50ms digital delay to the audio to get it synced up with the video. John
Posted: Wed Nov 15, 2006 2:28 pm
by Richard
I just received a mailer for ISF folks about an Alchemy D.DaD external solution.
http://alchemy2.com/
Unknown and untested but it is MonsterISF certified.