The talk is about the programming language Liquidsoap, which is a scripting language for creating online audio streams. The speaker discusses the growth of the Liquidsoap community and the new features that have been added to the language, including language changes and integration with FFmpeg. They also demonstrate how Liquidsoap can be used to create complex audio filters and describe the streaming algorithm used in Liquidsoap. The talk concludes with a discussion of future development and the challenges the project faces, such as attracting more developers and supporting offline processing.