Re: Does Video Processing Always Take Longer Than Audio?

On Sun, 04 Jan 2009 13:16:29 -0500, Del Mibbler <mibbler@large> wrote:

"Charles Tomaras" <tomaras@xxxxxxxxxxx> wrote:


"Ricky Jimenez" <rickyjim@xxxxxxxxxxx> wrote in message
news:a850m4l5urkddbeiiporp778dtjvodla2t@xxxxxxxxxx
I notice that some Blu-ray players and AV receivers have a feature
that allows you to delay the time audio reaches the speaker terminals,
by an adjustable number of microseconds. The idea is to compensate
for lip synchronization problems. Since there doesn't seem to be a
corresponding way to delay the time the video reaches the TV, should I
conclude that audio processing is always faster?

Yes for the types of relatively minor audio processing that would be done in
a home theater set up.

Unfortunately, people are much more sensitive to errors where video
lags audio since that is the reverse of our normal experience. There
are sveral "standards for what is an acceptable range of error, but
one common one is that audio should not lead video by more than 15 ms
or lag it by more than 45 ms.

That's an interesting number. I have a setting on my receiver where I
can adjust for sync problems by adjusting a delay of up to 200ms (at
least, I remember the number being 200, and I think that the unit is
"ms." It goes from 0 to 200 of something).

I've always wondered, if I see some apparent sync problems, what units
I should use to try to adjust. Should I start by adding a full 100?
Or should I start by adding 30? What number is so small that I
shouldn't even bother tweaking any further?

For example, if my first attempt is to add 30 ms, and it seems to help
a little bit, should I then add 10 ms more?

One other problem I have is that, while it's easy to see that the
audio isn't quite syncing with the video, it's harder to get my head
clear on which way it's off. I find myself actually pausing and
saying to myself, "Okay. I... SAW the door close... THEN I heard
it... So, that means... the audio is, um... BEHIND. And I've just
adjusted the Lip Sync correction to 60. So next, I should try...
um... " 30? 45? 55? 70? 90?

.

Relevant Pages

  • Re: DTV audio / vidio sync
    ... stay in sync. ... make delay adjustments differentially, any delay of some part of the A/V ...
    (sci.engr.television.broadcast)
  • Re: "live" MCE TV fall behind delay is accumulative
    ... > watched the ticker on a TV and on MCE TV window -- it got to be about 6 to ... > accumalative delay today is less than yesterday -- I did reboot since ... > I did not notice any jumps or skips or stops in the video or audio in the ...
    (microsoft.public.windows.mediacenter)
  • Re: Route signals through receiver or hdtv first?
    ... | delay capability in the surround amplifier. ... If the video delay is over your acceptance ... but also the audio out connections? ... The 5.1 sound from external sources needs in many cases to be ...
    (alt.tv.tech.hdtv)
  • Re: Route signals through receiver or hdtv first?
    ... | delay capability in the surround amplifier. ... If the video delay is over your acceptance ... but also the audio out connections? ... The 5.1 sound from external sources needs in many cases to be ...
    (alt.tv.tech.hdtv)
  • Re: Route signals through receiver or hdtv first?
    ... | delay capability in the surround amplifier. ... If the video delay is over your acceptance ... but also the audio out connections? ... The 5.1 sound from external sources needs in many cases to be ...
    (alt.tv.tech.hdtv)