26 What about the audio codec delay? (MPEG-Audio)
Description
This article is from the MPEG FAQ, by Frank Gadegast phade@cs.tu-berlin.de with numerous contributions by others.
26 What about the audio codec delay? (MPEG-Audio)
Well, the standard gives some figures of the theoretical
minimum delay:
Layer-1: 19 ms (<50 ms)
Layer-2: 35 ms (100 ms)
Layer-3: 59 ms (150 ms)
The practical values are significantly above that. As they
depend on the implementation, exact figures are hard to
give. So the figures in brackets are just rough thumb
values.
Yes, for some applications, a very short delay is of critical
importance. E.g. in a feedback link, a reporter can only talk
intelligibly if the overall delay is below around 10 ms.
If broadcasters want to apply MPEG audio coding, they have to
use "N-1" switches in the studio to overcome this problem
(or appropriate echo-cancellers) - or they have to forget
about MPEG at all.
But with most applications, these figures are small enough to
present no extra problem. At least, if one can accept a Layer-
2 delay, one can most likely also accept the higher Layer-3
delay.
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