Media Centre-Vista- Lipsync

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Brendan

I have a problem here. In the TV reception mode there is a significant
lipsync failure and I find this quite distracting. Anybody got any ideas
please?
 
Loss of audio/video synch is a frequent issue in digital transmission: if
you ever subscribed to any of the satellite services you would be very
familiar with this.
The problem is in the signal source, not the recording medium.
 
--->
Loss of audio/video synch is a frequent issue in digital transmission:
if you ever subscribed to any of the satellite services you would be
very familiar with this.
The problem is in the signal source, not the recording medium.
Click to expand...

I don't believe this to be true at all. I've subscribed to DirecTV for
over 10 years and have NEVER had any of my channels be out of sync
between voice and picture. TV cards inside computers tend to have
individual drivers for voice and video. If either of these drivers are
delayed by higher priority interrupts, the sound could very well get out
of sync.

Questor
 
--->
I have a problem here. In the TV reception mode there is a significant
lipsync failure and I find this quite distracting. Anybody got any
ideas please?
Click to expand...

Brendan:

Does this happen with clips played on the Windows Media Player or just
when you are in TV mode? Does this happen on web sites with Flash
Player running a video?

Questor
 
Not so much different drivers maybe but different pieces of hardware
capturing the audio and video streams during recording. TV capture cards
introduce a time delay to accommodate special viewing features like pause.
There's no problem if the audio stream is also routed through the capture
card but in some cases during recording the audio stream bypasses the
capture card straight to the PC sound device which results in the sound
being out of synch with the time delayed video.
 
--->
Not so much different drivers maybe but different pieces of hardware
capturing the audio and video streams during recording. TV capture cards
introduce a time delay to accommodate special viewing features like
pause. There's no problem if the audio stream is also routed through the
capture card but in some cases during recording the audio stream
bypasses the capture card straight to the PC sound device which results
in the sound being out of synch with the time delayed video.
Click to expand...

That's what I was alluding to. Hardware drivers. Several years ago I
had an ATI All-In-Wonder (TV) card. If I used the direct video input
all was fine, but if I relied on the 'cable' input, there were times
that audio and video got out of sync. What stopped it was to make sure
that nothing was running in the background that would steal cycles away
from the CPU. Of course, the CPU speeds back then were pretty slow
compared to all the new stuff out there so this argument might just be
smoke and the original problem may be deeper.

Questor
 
Questor said:
--->

That's what I was alluding to. Hardware drivers. Several years ago I had
an ATI All-In-Wonder (TV) card. If I used the direct video input all was
fine, but if I relied on the 'cable' input, there were times that audio
and video got out of sync. What stopped it was to make sure that nothing
was running in the background that would steal cycles away from the CPU.
Of course, the CPU speeds back then were pretty slow compared to all the
new stuff out there so this argument might just be smoke and the original
problem may be deeper.

Questor
Click to expand...

There are other possibilities, like working with AC3 audio or variable
bitrate MP3 audio tracks. Both can easily become out of synch depending on
what you do with them. I've got another scenario where the direct audio from
my TV tuner card isn't recognized by a lot of capture software. It would be
very easy to miss the fact that video and audio streams were not coming from
the same place.. say direct TV capture for the video track but line in for
the audio, which would result in out of synch sound.
 
This can happen if you are piping your video output through one device (like
a DVR or other digital tuner) and the audio output through another device
(such as a stereo, home theatre system or the speakers on your PC). The
only reliable cure is to get both video and audio passing through the same
devices (HDMI cable to your TV, then from the TV to the home theater system,
for example).
 
Thank you all. To Questor- It appears that this happens only in WMP, Flash
Player as well as in the TV mode

Brendan
 
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