Differences between version 12 and predecessor to the previous major change of DVDVideoTerminology.
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| Newer page: | version 12 | Last edited on Monday, July 13, 2009 2:38:40 pm | by LawrenceDoliveiro | Revert |
| Older page: | version 11 | Last edited on Tuesday, December 30, 2008 6:55:42 pm | by LawrenceDoliveiro | Revert |
@@ -1,7 +1,7 @@
Some of the more esoteric terms and concepts you may come across in [DVDVideo].
-A ''packetized elementary stream'' (PES) is just an [MPEG] stream. "Packetized" simply means that the data for each stream is broken up into blocks (which seem to be called both "packets" and "packs")
which are interleaved (''multiplexed'') together in the file. The minimum unit
of interleaving is called
the "VOBU" (Video Object Unit): this always begins with data
for the navigation stream, followed by data
for the other streams in some arbitrary order
.
+A ''packetized elementary stream'' (PES) is just an [MPEG] stream. "Packetized" simply means that the data for each stream is broken up into blocks which are interleaved (''multiplexed'') together in the file. In DVD-Video, these packets are grouped together into ''packs''
of 2048 bytes,
the same size as a sector on the disc. Packs are in turn grouped together into a
"VOBU" (Video Object Unit): this always begins with a pack
for the navigation stream, followed by packs
for the other streams (video, audio, subpicture)
.
One or more consecutive VOBUs make up a ''cell''. This is the basic unit of playback in DVD-Video. A cell can have associated program instructions in the virtual machine language, for example telling the player to keep looping the same cell, or jump to another cell.
The cell structure is used, among other things, to define ''parts of titles'' (PTTs), which ordinary users know as "chapters". Why they couldn't just call them chapters in the spec, I don't know...
