LibRCC API documentation: LibRCC, LibRCC UI.
Examples:
LibRCD Example: take a look, source.
LibRCC Simple Example: take a look, source.
Another LibRCC Example: take a look, source.
LibRCC UI Example: take a look, source.
RCC Recode Tool: take a look, source.
Articles and Presentations:
Четвертая Международная конференция разработчиков свободных программ на Протве: Presentation, Article.
You can have a look on the pdf with simplified diagram for LibRCC Library and RusXMMS2 patch.
Sample patch for mpg123 using LibRCC is available here. More patches can be downloaded from SourceForge.