...Internet Friendly Media Encoder supports adding subtitles and attachments, and can function as a remuxing tool with a Copy Stream option. It allows you to combine multiple video, audio, subtitle, and attachment streams into a single file, remove unwanted streams, or incorporate subtitles from another video without extracting. The software also supports AviSynth for advanced video processing.
The video and audio encoders are implemented in a plug-in style, enabling users to add their own compiled, optimized CPU architectures for increased speed. ...