Re: [Avid-L2] V6 downconvert audio sync AJA

Conversions with AJA hardware are notorious for ditching sync between audio
and video. If you can spot it, you can compensate for it in sequence.
Otherwise, do separate layoffs. This is with KONA, LH, iO, etc. - I do
not rely on these to make conversions unless there's no audio involved. I
did extensive testing a few years ago and posted my findings on the Cow and
sent to AJA. They confirmed all of them. I made myself a cheat-sheet for
them, for the KONA 3. Here it is:

KONA 3 Output - Delay Compensation for Video Conversion

When not performing any conversion on resolution or frame rate, the KONA 3
is frame accurate in edit to tape for video and audio.

--
When upconverting (for example, 525i29.97 to 1080i29.97 - only resolution,
not changing frame rate) the output from KONA 3 is frame accurate for audio
and 1 frame late for video.

To compensate for this, shift video in sequence earlier by one frame.

When downconverting (for example, 1080i29.97 to 525i29.97 - only
resolution, not changing frame rate) the output from KONA 3 is frame
accurate for audio and 1 frame late for video.

To compensate for this, shift video in sequence earlier by one frame.
--

--
When converting (1080sf23.976 to 1080i29.97 - adding pulldown only, not
changing resolution) the output from KONA 3 is frame accurate for both
video and audio.
--

--
When crossconverting (720p59.94 to 1080i29.97) the output from KONA 3 is
frame accurate for video and audio is one field early in 29.97i.

When downconverting (720p23.976 to 525i29.97) the output from KONA 3 is
frame accurate for video and audio is one field early in 29.97i.

When crossconverting (720p23.976 to 1080i29.97) the output from KONA 3 is
frame accurate for video and audio is approximately .4 frame early in
29.97i.

The only true solution to compensate for these types of conversions is to
do a separate edit for video (at conversion) and audio (with no
conversion), since audio can not easily be shifted accurately by less than
a frame.

On Wed, Apr 11, 2012 at 4:41 PM, Nigel Gourley <
avid-l@outpostfacilities.co.uk> wrote:

> **
>
>
> Hi there,
>
> Is this a "feature"..
>
> V6 with AJA card. HD sequence, using the secondary output as downconvert to
> standard def. embedded audio output. The audio is probably 2 frames earlier
> than the vision. And even if you switch the project to SD it's still out..
>
> I can understand there is a delay with the downconvert but I would expect
> the pictures and sound to be the same..
>
> I can't see this on the web anywhere..
>
> Thanks
>
> N
>
> [Non-text portions of this message have been removed]
>
>
>

[Non-text portions of this message have been removed]

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