[Matroska-devel] Matroska Specs Notes

Pamel paul at msn.com
Fri Nov 28 03:41:57 CET 2003


In the Notes section of the Matroska specs I noticed a few odd things.

1. On the first line the word "Octet" is spelled wrong.

2. This line, "A Matroska file contains one or more segments. It can optionally
be safely started with the old 160-octets type header without the EOF char."
And it has a link to the old MCF header page.  Is there really any reason to
support this?

3.  This line, "There is currently no encryption defined. It will be defined
when an open DRM system will exist. It should work at Block level and/or Cluster
level and/or Track level and/or Segment level."  Encryption was just defined, so
shouldn't this be removed?

4.  This line, "The position in some elements refers to the position, in octets,
from the beginning of an element. The reference is the beginning of the first
Segment element. 0 = first level 1 element in the segment. When data is spanned
over mutiple "linked Segments" (in the same file or in different files), the
position represents the accumulated offset of each Segment. For example to
reference a position in the third segment, the position will be: the first
segment total size + second segment total size + offset of the element in the
third segment. "  Is this really used this way?  What if the first file is
damaged and missing some data, wouldn't that screw up the offsets for the other
files?  Also, "multiple" is misspelled.

5. This line, "The BlockAddition attached to the Block means that it must be
found in the same Cluster, after the Block and before the next Block. That means
that other elements like a CRC can be put in between. There is only one
BlockAddition per Block. "  Should that be "BlockAdditions" or
"BlockAdditional"?  Also, does it serve any purpose right now?

6.  The line, "Overlay tracks should be rendered in the same 'channel' as the
track it's linked to. When content is found in such a track it is play on the
rendering channel instead of the original track. The codec in this track may be
omitted if it should be rendered using the original stream."  First, is it
possible to list more than one stream that the track should be the overlay for?
Second, would the codec EVER not be identified?  That sounds a bit dangerous to
me.


Pamel






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