--- In [email protected], Bhairitu <[EMAIL PROTECTED]> wrote: > > sparaig wrote: > > --- In [email protected], Bhairitu <noozguru@> wrote: > > [...] > > > >>> Most of the features included in MPEG-4 are left to individual > >>> > >> developers to decide whether to implement them. This means that there > >> are probably no complete implementations of the entire MPEG-4 set of > >> standards. To deal with this, the standard includes the concept of > >> "profiles" and "levels", allowing a specific set of capabilities to be > >> defined in a manner appropriate for a subset of applications." > >> > >> --- cut--- > >> Do you see anything about QuickTime here? Do you really know anything > >> about video programming? Have you ever written a demuxer or muxer? Do > >> you know the MPEG format, sequence headers, etc? Have you ever written > >> a stream parser? > >> > >> Dream on. > >> > >> > > > > Why so hostile? > > > > > > I'm not being hostile but some of the stuff you're saying is like > someone who's never been to India telling me what India is all about > when I've been there. I've been on the steering committees for these > consortiums (not the MPEG-4 but some others). I've been to Apple > developer conferences and worked with Apple developer support. I've > developed on the Mac and in fact at the moment looking to pick up a used > Mac that can run OS X so that I can port some products to it. I have an > iMac here but I can't put OS X on it. The company I used to work for > started out very Mac centric. > > I also do some video development and had to even write a player for the > last product I did. I've also been working with digital video since > 1991 when I bought my first camcorder and capture box for the Amiga.
My first programming job was for Dave McClain, who helped finish AmigaDOS 1.0 for Commodore. We were doing software support for a video/accelerator card for Mac Plus and Mac SE. > Now if you want to talk about a superior computer, the Amiga was way > ahead of it's time (and the Lisa before that until Jobs killed it). > Eh. At $10,000 per box, the original Lisa was a tad expensive for most people. NeXT was far better, but still too expensive at $7000 per box. The Mac Mini is many times more powerful and versatile than either machine except on expansion slots, and only costs 1/10 of the NeXT cube. > Answer me this: what is the primary difference between MPEG-2 and > MPEG-4? It's a very simple engineering idea which overcomes a > limitation of MPEG-2 and in itself gave MPEG-4 (also h.263) more > compression. > The primary difference between MPEG-4 and MPEG-2 is NOT the compression- decompression algorithm (codec). That's just crazy. I.. mean... literally... crazy. MPEG-2 described how to store multi-channel audio and visual information. Basically, the options available with many DVD movies, such as different camera view, subtitles, dubbed/alternate audio, etc, as well as screen resolution and shape (although there's no built-in limit in MPEG-2 as to how many such options could be made available, the implementations put up hard limits due to space considerations). The MPEG-2 compression/decompression algorithm implements such things, but the DESIGN of MPEG-2 is the important issue. The implementation is secondary. In fact, no-one has thus far implemented every aspect of MPEG-4 in the same package, and many/most of the designers believe that no-one ever will--its just TOO versatile. Here's an overview of MPEG-4's design. Check out the figure on page 7 of the pdf and recall that MPEG-4 isn't limited JUST to visual/audio data. Computer data, such as instructions for arbitrary computers or Java programs or HTML webpages or whatever is inherently supported in MPEG-4, just as it is in QuickTIme. That's the reason why the QUickTime file format was chosen: The design of QT anticipated MPEG-4 in many ways so Apple had already done the design work for a file format to support MPEG4-like features, even though Apple hadn't implemented all of them at that time (and still hasn't): http://www.bbc.co.uk/rd/pubs/presentations/pdffiles/mpeg4gat.pdf [page 7] "This figure explains the way in which an audiovisual scene in MPEG-4 may be desribed as composed of individual objects. The figure contains compund media objects that group primitive media objects together. Primitive media objects correspond to leaves in the descriptive tree while compound medial objects encompass entire sub-trees. As an example: the visual object corresponding to the talking person and the corresponding voice are tied together to form a new compound media object, containing both the aural and visual compoonents of that talking person. "Such grouping allows authors to construct complex scenes, and enables consumers to manipulate meaningful (sets of) objects. "More generally, MPEG-4 provides a standardized way to describe a scene, allowing for example to: * place media objects anywhere in a given coordinate system; * apply transforms to change the geometrical or acoustical appearance of a media object; * group primitive media objects in order to form compound media objects; * apply streamed data to media objects, in order to modiy their attributes (e.g. a sound, a moving texture belonging to an object; animation parameters driving a synthetic face); * change, interactively, the user's viewing and listening points anywhere in the scene." > As Barry pointed out you're doing the same groundless thing for Apple > you do for TM. If anything I'm trying to help you get a better grasp on > how the computer industry works and how they develop technology. It's > not any ego trip for me, I'm just one of the many who worked "in the > valley" and have "been there, done that." I try to do the same thing in > explaining how mantra shastra works. > I hope you have a better grasp of THAT then of the difference between MPEG-2 and MPEG-4. Sheesh.
