# Mpeg 2 and Mpeg4??



## paychekkk (Jan 15, 2006)

Ok I'm a newbie, what is the difference between mpeg2 and mpeg4. I understand that dish is going towards mpeg4 in the new vip series recievers. Which format is better quality.
thanx
Mikey


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## James Long (Apr 17, 2003)

Better quality is a matter of opinion.
MPEG4 allows satellite companies to put more channels/content up per transponder.

JL


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## voripteth (Oct 25, 2005)

paychekkk said:


> Ok I'm a newbie, what is the difference between mpeg2 and mpeg4. I understand that dish is going towards mpeg4 in the new vip series recievers. Which format is better quality?


MPeg2 is an older compression algorithmn which indepdently compresses each frame. MPeg4 is a newer compression which is similar to MPeg2 but it adds in information to compress across a number of frames. For example if an item is moving across the screen the compression includes the item and describes how it moves. MPeg4 is much more computationally expensive than MPeg2 which is why Dish is having a hard time getting real time compression to work well. There has been non-realtime MPeg4 compression on the PC for years. Hopefully providers will supply pre-encoded MPeg4 directly to dish so we can benefit from quality without waiting realtime encoders to get up to speed. (Heck, movies certainly don't need realtime compression.)

With the same compression parameters, MPeg4 will be a much smaller file. Of course as JL comments it depends on what Dish decides to do with this savings. They can improve the image quality by reducing the compression and use the same space as MPeg2 or they can use the extra space to squeeze in more channels at the same quality. The latter is much more likely than the former. There are rumors that once realtime Mpeg4 gets better then some of the HD channels will switch back to 1920x1080. Time will tell.


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## tnsprin (Mar 16, 2003)

voripteth said:


> MPeg2 is an older compression algorithmn which indepdently compresses each frame. MPeg4 is a newer compression which is similar to MPeg2 but it adds in information to compress across a number of frames. For example if an item is moving across the screen the compression includes the item and describes how it ...


Mpeg2 does not simply compress each frame. It does compress information across a number of frames. Your mpeg4 description is essentially true for mpeg2, except that mpeg4 is newer, more cpu intensive, and can compress the same info in about 1/2 the space as mpeg2.

IBBPBBPBBPBBPBBI


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## tnsprin (Mar 16, 2003)

The home page for all the mpeg group is
http://www.chiariglione.org/mpeg/

The mpeg4 standard is
http://www.chiariglione.org/mpeg/standards/mpeg-4/mpeg-4.htm


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