Differences between current version and previous revision of MPEG.
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| Newer page: | version 27 | Last edited on Sunday, January 10, 2010 2:00:47 pm | by LawrenceDoliveiro | |
| Older page: | version 26 | Last edited on Sunday, January 10, 2010 1:39:41 pm | by LawrenceDoliveiro | Revert |
@@ -15,9 +15,9 @@
* MPEG-3 was supposed to be a standard for use in HDTV. It was abandoned when it was realized that these needs could be easily met by either MPEG-2 or MPEG-4. Hence there is no MPEG-3.
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-* MPEG-4 was apparently based on Apple's QuickTime technology, and includes more interactive features beyond basic audio and video playback.
+* MPEG-4 was apparently based on Apple's QuickTime technology, and includes more interactive features beyond basic audio and video playback. But as usual it also introduced a new video codec, also known as [H.263|ITU-T] or “MPEG-4 Part 1”. Though nowadays people are mainly using the newer H.264, also known as “MPEG-4 Part 10”
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An MPEG file contains one or more "streams". Thus, video is one stream, and audio is another stream; even if the audio is stereo with two or more channels, that is still one stream. MPEG files on DVD-video discs can contain multiple audio streams for soundtracks in different languages, as well as "private" streams (in formats not defined by the original MPEG specifications, but by the DVD-video specification) for holding subtitles and trick-play data. Streams are ''multiplexed'', which means that, as the file is read sequentially, you encounter blocks of data belonging to each stream in turn, which are meant to be played at the same time. This allows a player to process all the streams concurrently, without having to continually jump
around the file.
