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Posted by Rick Merrill on 11/17/05 22:02
Doc wrote:
> You may have seen my other thread re: OOS audio problems. To recap, when
> recording to h/d via Firewire passthrough from analog VCR through a Sony
> Dig8 cam, the audio gets out of sync, it gets progressively worse the
> farther into the program you get...
This is similar to what will happen if you try (and fail) to convert a
DVD to MPEG2! DVD have audio recorded in AC3 at 44.1 kHz, while the
standard for MPEG2 is Level 2 at 48 kHz sampling rate. What happens
is the 44 is played back at 48 making the audio LEAD the video!!!
There is no really good solution to this problem that has cost me
several long days and a few arrows in the rear end. One tool will
insert blanks in the audio to "lock" it (but as you might imagine
this does not work well with music!), and another tool will drop
some video frames every now and then, making the video shorter than
expected but keeping the audio in sync!
Now the nearly perfect solution would be to multiply the 44 by 12
to 528 kHz then divide the 528 kHz down by 11 to 48 khz - but that is a
LOT of processing.
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