The Fastest Video Converter and Compressor is a versatile app that supports almost all video formats, including MP4, MKV, AVI, 3GP, MOV, MTS, MPEG, MPG, WMV, M4V, VOB, and FLV. It can convert, compress, and change the resolution, frame rate, and bitrates of a video file. Additionally, it can convert video files into audio formats like MP3, AAC, AC3, OGG, M4A, and WAV. The app also allows users to trim/cut both audio and video and merge audio and video files.

The app's key features include video conversion and compression, with support for a wide range of formats, including MP4, MKV, AVI, 3GP, FLV, MTS, M2TS, TS, MPEG, MPG, WMV, M4V, MOV, VOB, F4V, WEBM, DAV, DAT, MOVIE, MOD, MXF, LVF, and H264. Users can choose from predefined 4K resolution to 240P or put any custom resolution. They can also choose from any predefined frame rates or put any custom frame rate. The app supports existing subtitles tracks of the video or upload subrip, mov_text, srt, webvtt, vtt format subtitles. Users can choose from existing audio tracks of the video to keep or add external audio tracks of mp3, aac, m4a, wav formats.

The app also features a video merger that allows users to join/merge/concat multiple videos into one video in sequential, Top-Bottom, or Side-By-Side style. Users can also cut and trim their video files, keeping part of the video they selected or removing the selected part of the video if they enable the REMOVE SELECTED switch. The app also allows users to convert videos to almost any audio format and compress the audio. Users can cut and trim their audio files, keeping part of the audio they selected or removing the selected part of the audio if they enable the REMOVE SELECTED switch.

The app also features an audio converter that allows users to convert and compress their audio to almost any audio format, including MP3, M4A(AAC), M4B(AAC), AC3, WAV, OGG, and FLAC. Users can choose between mono and stereo channel and select sample rate from 8K to 48K. The app also supports batch processing, allowing users to queue multiple files for processing. The software uses source code of FFmpeg, and the instruction to compile and build the library is in the readme file inside it.