White Paper M600

Media formats

Audio formats

Format

Description

 

 

AAC-LC

Advanced Audio Coding. AAC is the latest audio coding standard, defined in the

 

MPEG-2 standard and is used for high-quality audio compression. AAC provides higher

 

quality than MP3 at the same bit rate, or for the same audio quality it uses a 30 per cent

 

lower bit rate. It supports the coding of multichannel audio, with up to 48 main chan-

 

nels and 16 low-frequency channels. The AAC offers three different profiles to facilitate

 

trade off between quality, memory and processing power requirements. They include:

 

Main Profile (MP), Low Complexity (LC) and Scalable Sampling Rate (SSR). The Media

 

player can play AAC-LC format audio which is encoded into an MPEG-4 file or stream.

 

The Sound recorder use the AAC-LC format for recording.

 

 

AMR-NB

Adaptive Multi Rate. AMR-NB is a speech compression format that is highly optimized

 

for the mobile environment, requiring as little as 4.75 Kbps bandwidth. AMR-NB is used

 

to convey voice recordings in MMS, 3GPP video clips or streams. M600 records AMR

 

using 12.2 Kbps with a sample rate of 8 kHz.

 

 

AU

Similar to WAV, this is an audio format commonly used in the Macintosh, Unix and

 

Java™ worlds. It is not commonly used for content on mobile devices.

 

 

iMelody

A format commonly used for monophonic ringtones. (M600 ringtones can use up to 40

 

voices.)

 

 

MIDI

Musical Instrument Digital Interface.

 

MIDI is not a recording of music, but a description which enables a local synthesizer to

 

play the music from the instructions included in the MIDI file. Since a MIDI file only rep-

 

resents player information, it is far more concise than formats that store the sound

 

directly. An advantage is very small file sizes. A disadvantage is the lack of specific

 

sound control. MIDI is ideal for polyphonic ringtones. (M600 ringtones can use up to 40

 

voices.)

 

 

SP-MIDI

SP-MIDI stands for Scalable Polyphony MIDI. SP-MIDI is based on the MIDI format and

 

adapted for mobile phones and other portable products. The objective is to secure

 

interoperability between products with different sound capabilities.

 

Initial recommendations for using SP-MIDI in 3GPP™ applications are discussed in a

 

separate document, Scalable Polyphony MIDI Device 5-24 Note Profile for 3GPP™.

 

 

MP3

MP3 is the file extension for MPEG audio layer 3. Layer 3 is one of three coding

 

schemes (layer 1, layer 2 and layer 3) for the compression of audio signals. Layer 3

 

uses a very efficient compression method, removing all irrelevant parts of a sound sig-

 

nal that the human ear cannot perceive. The result is, CD digital audio (CDDA) is con-

 

verted to MP3 with almost untouched quality, compressed by a factor of around 12.

 

The high compression of audio in MP3 files makes them relatively small, though MP3

 

files can be created with different size and quality compromises. The small file size,

 

together with the excellent sound quality, are the main reasons for the MP3-format’s

 

massive popularity when sharing music over the Internet.

 

 

RMF

Rich Music FormatTM. A file format developed by Beatnik combining the compact size

 

of MIDI files with the high quality of sampled sound.

 

 

36

February 2006

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Sony Ericsson M600 manual Media formats, Audio formats, Format Description