<s>
G.728	B-Algorithm
is	O
an	O
ITU-T	O
standard	O
for	O
speech	B-Application
coding	I-Application
operating	O
at	O
16kbit/s	O
.	O
</s>
<s>
It	O
is	O
officially	O
described	O
as	O
Coding	O
of	O
speech	O
at	O
16	O
kbit/s	O
using	O
low-delay	O
code	B-Algorithm
excited	I-Algorithm
linear	I-Algorithm
prediction	I-Algorithm
.	O
</s>
<s>
Technology	O
used	O
is	O
LD-CELP	B-Algorithm
,	O
low-delay	O
code	B-Algorithm
excited	I-Algorithm
linear	I-Algorithm
prediction	I-Algorithm
.	O
</s>
<s>
Delay	O
of	O
the	O
codec	B-General_Concept
is	O
only	O
5	O
samples	O
(	O
0.625ms	O
)	O
.	O
</s>
<s>
The	O
linear	O
prediction	O
is	O
calculated	O
backwards	O
with	O
a	O
50th	O
order	O
linear	B-Algorithm
predictive	I-Algorithm
coding	I-Algorithm
filter	O
.	O
</s>
<s>
The	O
excitation	O
is	O
generated	O
with	O
gain	O
scaled	O
VQ	B-Algorithm
.	O
</s>
<s>
In	O
1994	O
a	O
bit	O
exact	O
fixed	O
point	O
codec	B-General_Concept
was	O
released	O
.	O
</s>
<s>
G.728	B-Algorithm
passes	O
low	O
bit	O
rate	O
modem	B-Application
signals	O
up	O
to	O
2400	O
bit/s	O
.	O
</s>
<s>
Also	O
network	B-Architecture
signaling	O
goes	O
through	O
.	O
</s>
<s>
The	O
complexity	O
of	O
the	O
codec	B-General_Concept
is	O
30	O
MIPS	O
.	O
</s>
<s>
2	O
kilobytes	O
of	O
RAM	B-Architecture
is	O
needed	O
for	O
codebooks	O
.	O
</s>
<s>
Mean	O
opinion	O
score	O
for	O
G.728	B-Algorithm
is	O
3.61	O
.	O
</s>
<s>
The	O
essence	O
of	O
CELP	B-Algorithm
techniques	O
,	O
which	O
is	O
an	O
analysis-by-synthesis	B-Application
approach	O
to	O
codebook	O
search	O
,	O
is	O
retained	O
in	O
LD-CELP	B-Algorithm
.	O
</s>
<s>
The	O
LD-CELP	B-Algorithm
however	O
,	O
uses	O
backward	O
adaptation	O
of	O
predictors	O
and	O
gain	O
to	O
achieve	O
an	O
algorithmic	O
delay	O
of	O
0.625	O
ms.	O
</s>
<s>
RealAudio	B-Algorithm
28.8	O
is	O
a	O
reduced-bitrate	O
variant	O
of	O
this	O
standard	O
,	O
using	O
15.2	O
kbit/s	O
.	O
</s>
