10.3.9 HD Bouncing to disc: Missing sampls at start

[rantanplan]

Hi there,

I did a mix (5.1 movie) and bounced it to disc, using "physical output" as source.

After this, I imported the resulting files and spoted them to the start marker.
It's out of sync.
The strange thing is that its content is in advance, not delayed! I.e. there must be missing a few samples, like .5 frame...
How can this be? Is this a known issue in 10.3.9?

Cheers,
Till

[Chief Technician]

Originally Posted by rantanplan

Hi there,
The strange thing is that its content is in advance, not delayed! I.e. there must be missing a few samples, like .5 frame...
How can this be?

Was delay compensation enabled? Does your session exceed the amount of available delay compensation? If you spot the tail of your bounce to the tail of your bounce selection, reverse the polarity on the bounce, and press play from the start, do you hear silence (perfect cancellation)? If so, the gap between the start of your bounce selection and the start of your actual bounce file would be the number of missing samples. What is that number? What is your H/W buffer size? What is the session's sample rate?

[rantanplan]

Yes, delay compensation was enabled, of course...

How do I find out, if the session exceeds the amount of available delay compensation?

Start marker = start of bounce. The length is exactly the same, so end of imported sequence = end marker of bounced session.

No silence but echo of transients... As I stated above the content was not delayed but advanced of .5 frame at 24fps = 20.8ms

If HW buffer and sample rate has anything to do with this, I wonder what the delay compensation is for?
SR was 48k, buffer size was the smallest value (1024?).

Edit: HW buffer size is much lower of course, like 64

[rantanplan]

I just read on DUC that there is an issue when chaining two aux faders...
So i guess that's the issue in my case:

I'm using a 5.1 master bus for a 2.0 downmix:
DX tracks -> DX bus -> DX aux fader -> 5.1 bus -> downmix fader

[Chief Technician]

Originally Posted by rantanplan

I just read on DUC that there is an issue when chaining two aux faders...

Where did you read this?

[rantanplan]

Originally Posted by Chief Technician

Where did you read this?

http://duc.avid.com/showpost.php?p=2184668&postcount=3

... but I just realized that it is a PT11 problem...

[Chief Technician]

Originally Posted by rantanplan

How do I find out, if the session exceeds the amount of available delay compensation?

Is the DLY indicator in the Edit window red (exceeded) or green (OK)?

Originally Posted by rantanplan

Start marker = start of bounce. The length is exactly the same, so end of imported sequence = end marker of bounced session.

No silence but echo of transients... As I stated above the content was not delayed but advanced of .5 frame at 24fps = 20.8ms

Do you have any active tracks whose outputs are dummy busses? A dummy bus is a bus assigned to any track output that is not used as the input for any track in your session.

Originally Posted by rantanplan

If HW buffer and sample rate has anything to do with this, I wonder what the delay compensation is for?
SR was 48k, buffer size was the smallest value (1024?).

Edit: HW buffer size is much lower of course, like 64

I asked about the HW buffer size because if the amount of offset is divisible by the hardware buffer size, then it is possible that it is a buffering issue.