[ogg-dev] The use for an XML based metadata format

Conrad Parker conrad at metadecks.org
Mon Sep 10 17:33:43 PDT 2007

On 11/09/2007, Ian Malone <ibmalone at gmail.com> wrote:
> Embedding in Ogg is the simple bit; the only point of contention
> being whether you use a magic number to label it as metadata or
> just package XML and let the parser sort it out.  (With a bit
> more experience under my belt I'm persuaded a magic number might
> be worthwhile, otherwise there'll be someone who hardcodes their
> app to expect XML to be a metadata stream).

Agreed, having a magic identifier at the beginning of the stream is
useful where you only need to decide how to deal with a track (logical
bitstream), for example in the demux stage of a player. It is also
useful in a server that does stream recomposition or selection without
decode (eg. serving a temporal subset of the stream, or selecting
language tracks).

For CMML, we first tried just using raw XML from byte 0 but later opted for
using a binary header with magic identifier in the first (bos) packet
for these reasons.



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