What is QWinFF?
QWinFF is a GUI for FFmpeg, a powerful command-line media converter. FFmpeg can read audio and video files in various formats and convert them into other formats. QWinFF provides an intuitive graphical interface and a rich set of presets to help you use ffmpeg easily without having to type a single command. Advanced users can also adjust conversion parameters like bitrate and sample rate in detail.
The project is still developed as of 2018, but latest version, 0.2.1, dates back August 2015. It can be still downloaded from the official website.