Lee, I am late in answering, but I seem to be always late. God will
probably have to postpone my death .
But I did want to thank you for this interesting piece of email.
Motion Picture Experts Group. Who would have thought! My thoughts did
not get farther than a peg with an M on top!!!!. I did print this
out, it is amazing. Thanks so much. Now I can shine to my friends
who have ONLY Dells.
I now begin to wonder what TIFF stands for.
Thanks again for that thorough explanation
Marta
On Jun 28, 2009, at 19:38 PM, Lee Larson wrote:
On Jun 28, 2009, at 6:00 PM, Marta Edie asked:
And one questions begets another: what is the difference between
mp4 and mp3 . Methinks that somehow i cannot send files easily
when they are in mp4.
There's a computer industry committee, formed in the late 1980s
called the Motion Picture Experts Group (a.k.a. MPEG). Their job is
to define standards for compressing and encoding sound and video
for playback on computers. They've come out with a series of
definitions called the MPEG standards.
Their first set of standards is called MPEG-1 and came out in the
early 1990s. The ubiquitous mp3 sound files are technically MPEG-1
Level 3 sound files.
In the late 1990s, their fourth revision was issued and was called
(big drum roll!) MPEG-4. The mp4 sound files are one type of sound
file under the MPEG-4 umbrella. I think the mp4 and m4a files are
the same, and Apple seems to use both extensions. Apple uses m4b
when the mp4 files are bookmarked, such as with audio books and
some podcasts.
In theory, mp4 files should be playable on any platform, as long as
modern software is installed. Problems arise because mp4 is really
a container format rather than a sound format. This means that
there are several different ways to encode and compress the data
contained therein. These different methods are called codecs. Not
all developers choose to support all the standard codecs.
It is an interesting tidbit that the MPEG-4 specifications were
largely based on Apple's QuickTime and Apple holds several
important patents for ideas used in MPEG-4.
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