Introduction; What Is The Security Player; Encoder; Decoder - inout S-01 User Manual

User manual S-01 v.
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Introduction

1.1 What is the Security Player?

Security Player is a device that can reproduce audio messages registered on Compact
Flash (solid state memory), after a specific binary combination of input commands.
1.2 What is Mp3?
Mp3 is an acronym for Mpeg-1 layer 3. This is an audio compression standard which
eliminates sounds which the human ear cannot hear via a psycho-acoustic algorithm. The
purpose of this compression is to reduce the space taken up by an audio file while still
ensuring excellent quality. The greater the compression, the less the audio quality. The
right compromise, which guarantees a quality comparable to that of a Compact Disc, is
128 Kbps (thousands of bits per second) which represents the most widely used manner,
and reduces the size of an uncompressed file by 10 times.

1.3 Encoder

Software which compresses audio CDs or wave files into MP3s. There are many software
of this kind, and it is virtually impossible to say which is the best.

1.4 Decoder

Software which decompresses an MP3 audio file in order to send it to a digital-analog
converter and reconstruct the original audio signal.

1.5 Player

Hardware and software system able to read MP3 audio files. Security Player is able to
carry out this function.

1.6 Wave

High quality audio format (extension .wav), compatible with the tracks of normal music
CD's. If one uses a wave file in format 44.1 KHz/sec. at 16 bit in stereo, one will get
exactly the same quality as a music CD, but the size of the file is about 10Mb per minute.
1.7 Audio compression in various formats.
The following graphic shows the space taken up by an uncompressed audio file of about 5
minutes (.wav) and compressed in MP3 at 128Kbps (MP3).
Wave 51,1 MB
MP3 4,6 MB
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