[Matroska-devel] EBML specification component for review - Element Data Size
jerome at mediaarea.net
Fri May 1 17:07:45 CEST 2015
Le 01/05/2015 16:55, wm4 a écrit :
> Here I'd ask what the exact value of "unknown size" is. Sure, all bits
> are 1, but how many 1 bits are needed? It's a variable-length
> encoding. For example, the byte 0xFF has all bits set. Does this mean
> the length is unknown? (I think it is in EBML, not quite sure right now.)
the ebml spec is not clear, but I understand from index.html (the
matroska spec), thanks to "-2" everywhere, that:
0111 1111 1111 1111
0011 1111 1111 1111 1111 1111
0001 1111 1111 1111 1111 1111 1111 1111
are all reserved for an unknown size.
It makes sense because we can choose the size of "Data size" (and chose
8 bytes if we have no idea of the size of the block at the end of the
but "an Element Size encoded to all 1's" in the spec is not clear and
should be reworded.
I propose "Any data sizes composed entirely of 1's after the first 1
indicates that the size is unknown."
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