The Pre-processing Unit of MPEG-1 Layer III

Introduction

The pre-processing unit of MPEG-1 Layer III (MP3)

¨ Bitstream parse

¨ Huffman decoder

¨ De-quantization

¨ Stereo process

¨ Aliasing reduction

Features

Bitstream parse

A frame consists of five parts:

¨ Header

¨ CRC

¨ Side information

¨ Main data

¨ Ancillary Data

Huffman decoder

¨ 34 Huffman tables

¨ about 90% of the area is consumed by LUT

De-quantization

Using the following equations:

Stereo process

¨ MS stereo

and

¨ Intensity stereo

and

Aliasing reduction

Results

Uniqueness of this design

1.Huffman decoder

We analyzed 100 different kinds of songs and partition LUT into three part

2. De-quantization

There are three ranges with its dedicated operation for the whole range as follows:

From Si = 1 to 256:

Find the value of f(Si) from the look-up table.

From Si = 257 to 2048:

Where rem (Si/8) means the remainder of (Si/8)

From Si=2049 to 8191:

Architecture

Chip summary

Technology	0.25um 1P5M
Die size
Clock rate	3MHz
Gate count	54206
Power	19.328mW

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