Operation Manual

Page 18

Digital audio terms

AAC

Advanced Audio Coding (AAC) is one of the audio compression formats defined by the MPEG-2 spec-

ification. AAC used to be called NBC (Non-Backward-Compatible), because it is not compatible with

the MPEG-1 audio formats. AAC may eventually replace MP3 since it offers better sound quality and

greater file compression.

Bitrate

Bitrate denotes the average number of bits that one second of audio data will consume. The size of a

digital audio file is determined by the bitrate used when encoding the file. The higher the bitrate used,

the higher the sound quality and the larger the file size. For example, with MP3, a bitrate of 128k is

usually very close to CD quality, and takes up about 1MB per minute of music. At a 64k bitrate, the

sound quality is similar to that of an FM radio signal, but you may get around two minutes of music in

that same 1MB of storage space.

CDDB

CD Database (CDDB) is a vast database of CD information that includes disc name, song titles and

other information. CDDB supports hundreds of different third party software CD players. Access to the

CDDB service is offered free of charge to end-users. Visit the CDDB Web site

for more information.

DRM, security

Digital Rights Management (DRM) technologies protect copyright ownership of digital information.

DRM became an issue with the rise of MP3 technology and Internet distribution of music. DRM plat-

forms serve as a security “wrapper” around digital audio supporting Internet distribution while at the

same time protecting and managing rights related to that digital information.

The security mechanism in the Rio supports several secured file formats. When you download a

secure track from a CD or the Web to the Rio, you must have the licence associated with the track. If

the player doesn't read a corresponding licence for a track, the tracks themselves contain information

on where you can purchase them. Publishers can programme restrictions on how many times you can

play, copy, or distribute a song directly into the music files. Although the Rio includes security, it is still

able to accept and play standard MP3 files.

Codec

Depending on the context and kind of technology involved, codec may be defined in two ways. In tele-

communications, a codec is usually a “coding/decoding” chip used to translate between digital and

analogue transmissions. A modem uses one to interpret incoming analogue signals and converts the

digital data stream coming from the computer into analogue. A codec is also defined as a compres-

sion/decompression algorithm. Codecs are used to shrink large files or data streams, often for efficient

transmission over a network, and then decode them when they are displayed.

The Rio 600 supports the following digital audio file codecs:

•MP3

•WMA