This chapter describes the implementation of the methods for spectral envelope estimation, representation, manipulation, and application to synthesis documented in the previous chapters. The implementation proceeded in two steps: First, the spectral envelope and signal viewing program VIEWENV was developed in the MATLAB programming language. It allows for prototyping, interactive testing, and evaluation of the algorithms for spectral envelope estimation and manipulation. The architecture and the usage of the VIEWENV program is described in appendix 1.
Then, the spectral envelope function library was developed which combines the methods evaluated in the project, and makes them accessible to other programs. The principles of software engineering were applied to the development process.
This chapter is organised as follows:
First, some basic concepts of software engineering are introduced in section 7.1, and the notation used to document the design of the library and also of the VIEWENV program is explained in section 7.2. Then, some general considerations for the design and the implementation of the library are layed out in section 7.3, followed by the documentation of the design itself in section 7.4. Finally, the new SDIF file types used for permanent storage of spectral envelopes is described in section 7.5.
The description of the programs and the library, which follows in the next two chapters, is generally divided into two layers: a user manual, and a documentation of the program architecture, aimed at developers who want to extend or maintain the code, or at anybody who wants to get a deeper understanding of the system.