The document discusses audio devices and codecs. It defines audio devices as those that emit or receive sound, separating them into input and output types. Audio input devices allow sending audio signals to computers, while output devices play sound. Codecs are programs that compress and decompress audio data according to specific formats. Lossless codecs allow original data reconstruction, while lossy codecs lose some data for greater compression. Finally, the document outlines common sound formats including uncompressed, lossless compressed, and lossy compressed types.

1. By Xufeng and Victor

2. Index
 What is a audio devices?
 Example of audio input/output devices
 What are the codecs?
 Loss and Lossless codecs
 Sound Formats

3. What are audio devices?
 It is a device that emits or receive sound.There are
two types:
 Audio Input Devices: Allow a user to send audio
signals to a computer for processing, recording, or
carrying out commands.
 Audio Output Devices: Refers to any device that
attaches to a computer for the purpose of
playing sound.

4. Audio Input devices
 Input devices: Microphones, digital instruments.

5. Audio Output Device
 Output Device:

6. What Is a Audio Codecs?
 It is a computer program implementing
an algorithm that compresses and
decompresses digital audio data according to a
given audio file format audio format.

7. Lossless Codec
 It is a compressed data that permits the original data
to be reconstructed from the compressed data.
 Here are some examples: apple lossless audio
codec(ALAC), ATRAC Advanced lossless (AAL)

8. Lossy Codec
 It is a data encoding method that compresses data by
losing some of it.

9. Sound Formats
 It is a file format that lay up digital audio data on
a computer system.
 Types of formats:
 Uncompressed audio format: It is one major
uncompressed audio format.
 Formats with lossless compression: It stores data in
less space without losing any data.
 Lossy compressed audio format: It is a greater
reductions in file size by removing some of the data.