<s>
HDC	B-Algorithm
(	O
Hybrid	O
Digital	O
Coding	O
or	O
High-Definition	B-Algorithm
Coding	I-Algorithm
)	O
with	O
SBR	O
(	O
spectral	B-Algorithm
band	I-Algorithm
replication	I-Algorithm
)	O
is	O
a	O
proprietary	O
lossy	B-Algorithm
audio	O
compression	O
codec	B-General_Concept
developed	O
by	O
iBiquity	O
for	O
use	O
with	O
HD	O
Radio	O
.	O
</s>
<s>
It	O
replaced	O
the	O
earlier	O
PAC	O
codec	B-General_Concept
in	O
2003	O
.	O
</s>
<s>
It	O
uses	O
a	O
modified	O
discrete	O
cosine	O
transform	O
(	O
MDCT	O
)	O
audio	O
coding	O
data	B-General_Concept
compression	I-General_Concept
algorithm	I-General_Concept
.	O
</s>
