[streaming] OT: H.264 support and .3gp

[Warren Young]

Yusuf Mayet wrote:
> 
> What does MPEG-4 refer/mean to?

MPEG-4 is a huge, unruly bag of technologies.  I don't know of a single 
software package that implements *all* of MPEG-4.  See:

	http://en.wikipedia.org/wiki/Mpeg-4
	http://www.chiariglione.org/mpeg/achievements.htm

Colloquially, when you see "MPEG-4" given with no other qualifiers in a 
video context, MPEG-4 typically refers to MPEG-4 Part 2, the original 
video encoding method defined for the MPEG-4 family.  Part 2 was a mess, 
from a standards perspective.  It specified far more than has ever been 
actually put into practice, and the video only parts splintered through 
proprietary extensions like DivX and Microsoft's MPEG-4v3, perhaps 
because as-is it isn't dramatically better than MPEG-2.

H.264 was added to the MPEG-4 family a few years after the initial parts 
of MPEG-4 were standardized; it is also called MPEG-4 Part 10.  Part 10 
is a much more focused standard than Part 2, covering just video.  It 
takes the ideas in the video parts of MPEG-4 Part 2 and extends them 
further, making it valuable enough in terms of coding efficiency to woo 
many more people away from MPEG-2 and proprietary codecs than Part 2 
could.  It is likely that over the next few years, H.264 will crush Part 
2: it won't be used for new products, and old Part 2 products will 
either be updated to use H.264 instead, or will be allowed to slide into 
obsolescence.

> Is'nt is just the container, 

That's yet another confusing part about MPEG-4: it defines at least 
three different "container" formats.  There are program and transport 
streams (Part 1) similar to those of MPEG-2, then there is the QuickTime 
variant defined in Part 12, which is often associated with H.264, but 
not actually tied to it.

>  Can anyone explain the difference between MPEG-4 and H.264.

John Watkinson can: 
http://www.amazon.com/MPEG-Handbook-Second-John-Watkinson/dp/024080578X/