[Tommy]

Hi,

I've got a couple questions regarding the use of id's in an mxf file.

Are there any restrictions regarding the creation of UUID's or can
they be just random unique numbers? (including the use of UUID's
within UMID's)

I understand how the references work with regard to UUID's, but
am not clear whether UMID's need to match sometimes within an
mxf file.
UMID's are used in many places within an mxf file, including:

in the header metadata -
> in essence container data, linked package umid (p. 65 S377M)
> in each package, a package umid (p. 66 377M)
> in sourceclip subset, a SourcePackageId (p. 70, 72)

Then, in each edit unit's package metadata, there is a UMID
metadata field ( type = 0x83, SMPTE 331M p. 10)

In our mxf file, we plan to have a material package and a file
package in the header metadata, and then mpeg2 video along
with audio and timecode in the essence containers.

Can you please tell me where and how the UMID's need to match
up, and where unique UMID's are required?

Then 1 other question: we'd like to make our header metadata a fixed
size, and we have either 0, 2, 4, or 8 channels of audio.
Is it possible to use fill space in this way, ie, place filler everywhere
necessary when we have less than 8 channels of audio to keep the
header the same size? The documentation appears to indicate that
this is ok to do.

Thanks a lot, Tommy Schell