a2b invokes conversion tools in sequence to convert files from one type to another, possibly performing some extra processing along the way. Itis a wrapper for many programs like gif2png, latex2html, netpbm, mencoder, ffmpeg, oggenc, etc., that can convert content from one type to another. It can covert text, documents, images, audio, and video and more. Some examples: a2b test.mp3 test.ogg; mencoder_opts="-ss 60 -endpos 10" a2b video.avi clip.flv; a2b -g=subtitles dvd://8 movie.sub; a2b -q http://sam.nipl.net/ sam.aac. That last example downloads the author's Web page, converts it to text with lynx -dump, speaks the text with flite or espeak, and converts the audio file to AAC with faac.
Synth is a C++ template framework - a set of components that can be mixed and matched to build the right functionality; furthermore, components are loosely-coupled, designed to be both extensible and replaceable. Synth blurs the line between compile-time and runtime, and it does so by blending the static C++ type system, the dynamic values that need to be manipulated and formatted, including those from other languages, and the templates to do so. The name is an allusion to this synthesis process, which combines values to generate new ones (streams, files, strings, numbers, etc.)