1. VLC media player
Simple, fast and powerful media player. Plays everything: Files, Discs, Webcams, Devices and Streams. VLC media player is a free and open source media player and multimedia framework written by the VideoLAN project. VLC is a portable multimedia player, encoder, and streamer supporting many audio and video codecs and file formats as well as DVDs, VCDs, and various streaming protocols. It is able to stream over networks and to transcode multimedia files and save them into various formats. The default distribution of VLC includes a large number of free decoding and encoding libraries, avoiding the need for finding/calibrating proprietary plugins. VLC is a packet-based media player, and it can play the video content of some damaged, incomplete, or unfinished videos. For example, files still downloading via peer-to-peer (P2P) networks.
2. VirtualDub
Do you need quick capture and encoding capabilities for video on your desktop? VirtualDub is a free, Open Source solution specifically designed for that purpose. VirtualDub might lack the editing power of a general-purpose editor such as Adobe Premiere, but is streamlined for fast linear operations over video in return. It has batch-processing capabilities for processing large numbers of files and can be extended with third-party video filters.
3. avidemux
Edit your avi, mpeg and nuv. Process audio and video. Cut.
Avidemux is a free video editor designed for simple cutting, filtering and encoding tasks. It supports many file types, including AVI, DVD compatible MPEG files, MP4 and ASF, using a variety of codecs. Tasks can be automated using projects, job queue and powerful scripting capabilities.
Avidemux is available for Linux, BSD, Mac OS X and Microsoft Windows under the GNU GPL license. The program was written from scratch by Mean, but code from other people and projects has been used as well. Patches, translations and even bug reports are always welcome.
4. DVD Flick
DVD Flick aims to be a tool to convert various PC video formats to a DVD that can be played on pretty much any standalone DVD player. It can take a number of video files stored on your computer and turn them into a DVD that will play back on your DVD player, Media Center or Home Cinema Set. You can add additional custom audio tracks, subtitles as well as a menu for easier navigation. Its main target audience is people who know at least the basics about DVDs and video and audio files.
5. ffdshow
ffdshow is an advanced DirectShow filter and VFW codec that supports many audio and video formats. For example: H.264, MPEG-4, MPEG-2, H.263, VP3, VP6, Theora, MJPEG, SVQ3, MP3, AC3, DTS, E-AC3, AAC, and Vorbis. It includes a powerful filter set that can enhance the video quality - with filters for resizing, deinterlacing, and displaying subtitles - as well as audio quality through normalization, down-/upmixing, and resampling.