[FFmpeg-devel] [PATCH] libavformat/mxfdec.c: export the full UMID as metadata

tim nicholson nichot20 at yahoo.com
Tue Jan 6 09:03:08 CET 2015


On 05/01/15 20:41, Mark Reid wrote:
> Hi,
> This patch exports the full umid of packages as metadata. ffmpeg currently
> only exports the material number portion of the umid.
> 
> The new format is
>    <ISO label>-<length>-<instance number>-<material number>
> example:
>    060a2b340101010101010f00-13-000000-53dc416b9a770251060e2b347f7f2a80
> 

I think this is a good idea, but if we are going to make the change can
we make the exported format be SMPTE330 compliant? Annex C (normative)
states:-

"By default, the hexadecimal representation should be preceded by the
identifier ‘0x’. This default method of identification will result in 66
hexadecimal characters to represent a basic UMID as follows:
0x060A2B340101010501010D13 ... etc.
The hexadecimal letters should be encoded as upper case (A...F)."


> Some applications use the umids to link to mxf media instead using file paths.
> I've been using ffmpeg for some AAF work and have encountered
> MXF files with different ISO labels and having just the material number alone is not
> enough to link to media for Media Composer.
> 
> For more on umids, this paper explains them pretty well
> http://www.digitalpreservationeurope.eu/publications/briefs/UMID_Unique%20Material%20Identifier.pdf
> 
> umids also have a optional extened 32 bytes, but I've yet to see a file that
> has them.
> 
> Mark Reid (1):
>   libavformat/mxfdec.c: export the full UMID as metadata
> 
>  libavformat/mxfdec.c | 39 ++++++++++++++++++++++++++++++++-------
>  1 file changed, 32 insertions(+), 7 deletions(-)
> 


-- 
Tim.
Key Fingerprint 38CF DB09 3ED0 F607 8B67 6CED 0C0B FC44 8B0B FC83


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