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MXF with audio problem
http://freemxf.org/forum/viewtopic.php?f=2&t=259
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Author:  barabba [ Mon Nov 18, 2013 4:55 pm ]
Post subject:  MXF with audio problem

I have some files that crash the editing workstation.
I analyzed MXF files with an video and eight audio essences using MXF Analyser Professional.
For each audio track got errors like these:

<analyser:ByteOffset> 7328 </ analyzer: ByteOffset> <analyser:Message> The correct value for property SampleRate is 48000/1 and not 25/1 as encoded in the file. </ analyzer: Message> </ analyzer: Error>

where 7328 is the Byte Offset.
I would like to understand what the Byte Offset and what it refers to the error.

Thanks in advance

Author:  Matt Beard [ Fri Nov 22, 2013 12:49 pm ]
Post subject:  Re: MXF with audio problem

This is an issue with the revised MXF specification...

The original 2004 version of ST377 gave audio descriptors two sample rates, one intended to match the associated video sample rate (called Sample Rate) and one for the actual audio sampling rate (Audio Sample Rate). The table in Annex D.1 included the words "The field or frame rate of Essence Container (not the essence (pixel) sampling clock rate)" to try and ensure that this was interpreted correctly.

Unfortunately the 2009 version of ST377 changed the wording and redefined the meaning of Sample Rate to match the implementation of a specific manufacturer. This should have been caught during the ballot, but was missed.

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