On 24/03/05, dave nolan wrote:
> Hello all -
> I am not enough of a "computer bits" whiz to know the real bit-by-bit
> blood and guts of BWF metadata, but...
> As best I can understand from the EBU BWF standards, there are
> numerous "chunks" of metadata that are associated with BWF files - the
> "bext" (or "mext") chunk which contains the internationally agreed
> upon minimum metadata.
> Additionally there appears to be a way to define chunks that are
> unique to the needs of the originating client/institution:

The important point about an IFF file format (RIFF is simply a Microsoft
variant of the original format designed by Electronic Arts) is that the
reading program will ignore any chunks that it doesn't understand.

That means you can add new chunks containing metadata, comments
or whatever without making the file unreadable by older or simpler
programs. You don't get the incompatability that afflicts Word files,
for instance.

So an editing program as proposed could add new chunks as well as
modifying old ones.

The IFF format is not just for sound but covers all media types -
images, DTP, formatted text, 3D objects, etc. AIFF is another variant.
The header chunk tells you which type it is, so the 3-letter extension
on a filename is redundant (it should have been dropped when cp/m went
out of use).

Don Cox
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