[Matroska-devel] Clarification on CueRelativePosition

wm4 nfxjfg at googlemail.com
Fri Jul 19 16:30:22 CEST 2013

On Fri, 19 Jul 2013 16:21:19 +0200
Moritz Bunkus <moritz at bunkus.org> wrote:

> Hey,
> no, a new ID will not be used because the semantics of the element
> have not changed. mkvmerge has simply been writing invalid values. We
> cannot change EBML elements at wim simply because some muxer writes
> invalid values.

In this case, mkvmerge was the only muxer, and nothing used the new
elements until now anyway. However, there are already files in the wild
which contain the broken elements. In would require workarounds for old
files in new demuxer implementations for absolutely no reason.

Assigning a new ID would side-step this. Alternative muxers (if there
are any which use the new elements yet) would merely have to switch to
the new ID, after making sure that they write the elements correctly
(yes, it could be that muxers tried to duplicate these bugs by making
sure their output matches mkvmerge's).

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