|What is essence data of timecode component?
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|Author:||akira [ Mon Aug 28, 2006 7:53 am ]|
|Post subject:||What is essence data of timecode component?|
I am checking some MXF files including from internet.
I guess that the number of tracks of Top-Level File Package and the number of Delta Entries in Index Table Segments are same and corresponding order for frame mapping files.
Some MXF file contain a KLV Fill to timecode position at essence container.
Another MXF file contain system items and KLV fill.
The track number of timecode of both files is zero.
1. Is required entry for timecode component for index table segments ?
2. If no corresponding order between track of top-level file package and entry of index table segments,
is required to check 1st content package set for essence element key, track number of top-level file package, and address from index table, then make the mapping of track->index table->essence element.
Thanks to read
|Author:||Matt Beard [ Mon Aug 28, 2006 4:53 pm ]|
I think that the whole thing that you are asking here is "how do I tie the tracks in a top-level source package to the elements in an index table (as described by the delta array".
If so this is slightly tricky!
There is not a one-to-one relationship between the two items. There can be more or less elements indexed in an index table that tracks in the source package.
Some key facts about indexing:
* Timecode tracks are not held in the essence container, all the data is in the header metadata, so they will never get indexed.
* An index table may index each KLV fill in the essence container, but this is optional.
* A very basic index table just indexes the start of each edit unit, and it is up to you to locate each essence element in that edit unit.
* More complex index tables generally index each essence element such that you get the same number of indexed elements as there are essence tracks
* The order of tracks or track numbers is not related to the order in the index table - you have to read the first edit unit and work out which element relates to which track.
* You may find that something is indexed, but you can't identify it (because it is described by some dark metadata in the header) - in this case just ignore that element
* You may find that one or more essence tracks does not have an index element - if this is the case you just have to search for it - it is probably easiest to locate the start of the edit unit and scan all KLVs until you find the one you are wanting.
* Index tables are not easy
|Author:||akira [ Tue Aug 29, 2006 5:36 am ]|
|Post subject:||Thanks to answer|
Thanks Mr Matt Bread.
I see, and need to check 1st content package and key for track number.
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