Jump to: navigation, search


2,063 bytes added, 04:24, 15 June 2012
Reverted edits by WikiCleaner (talk) to last revision by Ogg.k.ogg.k
The category field in the BOS packet is a 16 byte text field (15 really, as it is zero terminated
in the bitstream itself). Its goal is to provide the reader with a short description of what kind
of [ web design] information the stream contains, eg subtitles, lyrics, etc. This would be displayed to the user,
possibly to allow to choose to turn some streams on and off.
This latter method may also be used if you already have an encoded Vorbis song
with no lyrics, and just want to add the lyrics without reencoding.
=== Metadata ===
Metadata can be attached to events, or to styles, bitmaps, regions, etc.
Metadata are free form tag/value pairs, and can be used to enrich their
attached data with extra information. However, how this information is
interpreted is up to the application layer.
It is worth noting that an event may not have attached text, so it is
possible to create an empty timed event with attached metadata.
For instance, let's say we have a documentary, with footage from various
places, as well as short interviews, and we want two things:
- tag footage with metadata about the location and date that footage was shot
- subtitle the interviews and tag those subtitles with information about the speaker
You can then create an empty Kate event for each footage part, synchronized
with the footage, and attach a new metadata item called GEO_LOCATION, filled
with latitude and longitude of the place the footage was shot at.
Similarly, for each subtitle event, a metadata item called SPEAKER can be
An empty event to tag a long 4:20 footage shot in Tokyo on 2011/08/12, and
inserted at 18:30 in the documentary could look like:
event {
00:18:30,000 --> 00:22:50,000
meta "GEO_LOCATION" = "35.42; 139.42"
meta "DATE" = "2011-08-12"
Here's a example for a line spoken by Dr Joe Bloggs at 18:30 into the documentary:
event {
00:18:30,000 --> 00:18:32,000
"Notice how the subtitles for my words have metadata attached to them"
meta "SPEAKER" = "Dr Joe Bloggs"
meta "URL" = ""
Notice how another metadata item, URL, is also present. The application
will have to be aware of those metadata in order to do something with it
though. Since those are free form, it is up to you to think of what
metadata you want, and make use of it.
Note that metadata may be attached to other objects, such as regions.
This way, you can for example create a region tagged with a name, and
track a person's movements with that region. Or you can tag a bitmap
with a copyright and a URL to a larger version of the image.

Navigation menu