[FFmpeg-devel] [PATCH 12/14] avformat/matroskasem: reorder some EbmlSyntax elements

Andreas Rheinhardt andreas.rheinhardt at gmail.com
Wed Apr 8 20:47:18 EEST 2020


Steve Lhomme:
> From: Steve Lhomme <robux4 at ycbcr.xyz>
> 
> So it's easier to match with the XSLT ordering which has limited possibilities
> (15 max criteria for all the syntax tables).
> 
I don't know XSLT at all, but this already raises alarm bells: If this
is so restricted, then this whole approach might be a non-extensible
dead-end.
(I e.g. pondered to remove all those EBML_NONE elements that are not
read at all at the moment from the syntax tables and instead add a
pointer to a zero-delimited array of uint32_t that contains all* the
EBML IDs of elements that may legitimately appear in said context, but
which we don't care about (yet). (Both list_elem_size as well as
data_offset of the sentinels are currently unused, so sizeof(EbmlSyntax)
needn't be increased for this.) Would this even be possible with your
approach?)

- Andreas

*: The current tables don't include all these elements.


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