Overview

The library converts data from MPEG-1 Audio Layer 3 stream data (hereinafter referred to as MP3) to PCM data. The library has been developed on the assumption that it is used in the field of data programming, thus allowing the switching between big and little endians and between floating and fixed point operations in compiling. The library is also mounted in standard C functions only, thus facilitating transplant to an operating system if the system has an environment for C-language development.

Functions

The library has the main function of decoding MP3 data and the following other functions:

• Handles big and little endians

Allows the switching between big and little endians in compiling since it corresponds to these endians.
• Fixed-point operations

Can make calculations using fixed-point operations. This allows the high-speed decoding of MP3 data even for systems that do not have the function of making floating-point operations although sound quality is slightly inferior.
• Samples output data

Can process output data without any operations by reducing the sampling rate for output results. It is possible to reduce the sampling rate to half and a fourth of that for MP3 data inputted.
• Converts stereo sound to monaural sound

Can forcedly convert stereo sound to monaural sound when decoding MP3 data. The ability to omit operations for stereo sound allows a reduction in data processing time.

Actual operations

Operating system required	Windows2000 Professional
Development environment	Visual Studio 6.0
CPU	Pentium3 800MHz

Operating system required	VxWorks5.3
Development environment	Tornado2.0 (Gnu Tool Chain)
CPU	MPC823 75 MHz (Power PC) 100 MIPS range