HDC (Hybrid Digital Coding or High-Definition Coding) with SBR ( spectral band replication) is a proprietary

lossy In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data si ...

codec A codec is a device or computer program that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder. In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or ...

developed by

iBiquity iBiquity Digital Corporation is a company formed by the merger of USA Digital Radio and Lucent Digital Radio. Based in Columbia, Maryland, with additional offices in Basking Ridge, New Jersey, and Auburn Hills, Michigan, iBiquity is a privately ...

for use with

HD Radio HD Radio (HDR) is a trademark for an in-band on-channel (IBOC) digital radio broadcast technology. It generally simulcasts an existing analog radio station in digital format with less noise and with additional text information. HD Radio is used ...

. It replaced the earlier

PAC Pac or PAC may refer to: Military * Rapid Deployment Force (Malaysia), an armed forces unit * Patriot Advanced Capability, of the MIM-104 Patriot missile * Civil Defense Patrols (''Patrullas de Autodefensa Civil''), Guatemalan militia and paramil ...

codec in 2003. In June 2017, the format was reverse engineered and determined to be a variant of HE-AACv1. It uses a

modified discrete cosine transform The modified discrete cosine transform (MDCT) is a transform based on the type-IV discrete cosine transform (DCT-IV), with the additional property of being lapped: it is designed to be performed on consecutive blocks of a larger dataset, where ...

(MDCT)

audio coding An audio coding format (or sometimes audio compression format) is a content representation format for storage or transmission of digital audio (such as in digital television, digital radio and in audio and video files). Examples of audio coding f ...

data compression In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compressio ...

algorithm.

References

External links

News story about switch to HDC
Audio codecs {{comp-stub