.AAC and .MP3

By: Jared Hendricks&

Billy Wolfram

.MP3 Pros

• Widespread acceptance, support in nearly all hardware audio players and devices.

• An ISO standard, part of MPEG specs.• Fast decoding, lower complexity than AAC or

Vorbis.• Vorbis produces an audio format specification

and software implementation.• Relaxed licensing schedule.

.MP3 Cons

• Lower performance/efficiency than modern codecs.

• Problem cases that trip out all transform codecs.

• Sometimes, maximum bitrate (320kbps) isn’t enough.

• No multichannel implementations.• Unusable for high definition audio (sampling

rates higher than 48kHz).

.MP3 Examples

• SanDisk - Clip Zip MP3 Player with 8GB.$59.99• Apple iPod nano 8 GB. $149.00

.MP3 Examples of Pictures

SanDisk - Clip Zip MP3 Player Apple iPod nano

.AAC Pros

• An international standard approved by the ISO• Flexible: supports several sampling rates (8000-

96000 Hz), bit depths, and multichannel (up to 48 channels)

• Several implementations, including free and high quality ones.

• Reaches transparency in most samples and for most users at around 150 kbps

• Part of MPEG-4 specs

.AAC Cons

• Problem cases that trip out all transform codecs.

• Heavily patented.• Increased complexity.• AAC comes in different “flavors” (object types:

AAC LC, AAC HE, AAC PS etc.).• Many (especially portable) players only support

LC (at the moment) so you can have files that are valid but your player won’t play them.

.AAC Examples

• Low-tech communication are often very simple communication boards or books, from which the user selects letters, words, phrases, pictures, and/or symbols to communicate a message.

• High-tech AAC aids permit the storage and retrieval of electronic messages, with most allowing the user to communicate using speech output.

.AAC Examples Of Pictures

Low Tech High Tech