25 How many audio channels? (MPEG-Audio)
Description
This article is from the MPEG FAQ, by Frank Gadegast phade@cs.tu-berlin.de with numerous contributions by others.
25 How many audio channels? (MPEG-Audio)
MPEG-1 allows for two audio channels. These can be either
single (mono), dual (two mono channels), stereo or
joint stereo (intensity stereo (Layer-2 and Layer-3) or m/s-
stereo (Layer-3 only)).
In normal (l/r) stereo one channel carries the left audio
signal and one channel carries the right audio signal. In
m/s stereo one channel carries the sum signal (l+r) and the
other the difference (l-r) signal. In intensity stereo the
high frequency part of the signal (above 2kHz) is combined.
The stereo image is preserved but only the temporal envelope
is transmitted.
In addition MPEG allows for pre-emphasis, copyright marks and
original/copy marks. MPEG-2 allows for several channels in
the same stream.
Continue to:
My Books
