4 C code structure

26.4423GPPANSI C code (fixed-point)Codec for Enhanced Voice Services (EVS)Release 17TS

This clause gives an overview of the structure of the bit‑exact C code and provides an overview of the contents and organization of the C code attached to the present document.

The C code has been verified on the following systems:

– IBM PC compatible computers with Windows 7 or 8 operating system and Microsoft Visual C++ 2010 compiler, 32 bit builds.

– IBM PC compatible computers with Linux operating system and GNU gcc compiler version 4.3.x, 32 bit builds.

ANSI‑C was selected as the programming language because portability was desirable.

4.1 Contents of the C source code

The C code distribution is organized as follows:

Table 1: Source code directory structure

Directory	Description
README.txt	information on how to compile
Makefile	UNIX style encoder Makefile
Workspace_msvc/	Directory for the MSVC 2010 project files
basic_op/	Source code files containing all ITU-T fixed-point basic operators.
basic_math/	Source code files contains mathematical fixed-point functions
lib_com/	Source code files used in encoder and decoder
lib_dec/	Source code files used solely in the decoder
lib_enc/	Source code files used solely in the encoder

The distributed files with suffix "c" contain the source code and the files with suffix "h" are the header files. The ROM data is contained in files named "rom_xxx" with suffix "c".

Makefiles are provided for the platforms in which the C code has been verified (listed above). Once the software is installed, this directory will have a compiled version of the encoder (named EVS_cod) and the decoder (named EVS_dec).

4.2 Program execution

The codec for Enhanced Voice Services is implemented in two programs:

– EVS_cod: speech/audio encoder;

– EVS_dec: speech/audio decoder.

The programs should be called like:

– EVS_cod [encoder options] <speech/audio input file> <parameter file>;

– EVS_dec [decoder options]<parameter file> <speech/audio output file>.

The speech/audio files contain 16-bit linear encoded PCM speech/audio samples and the parameter files contain encoded speech/audio data.

The encoder and decoder options will be explained by running the applications without input arguments. See the file readme.txt for more information on how to run the encoder and decoder programs.