Avidemux 2.5.1

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 a free open-source program designed for multi-purpose video editing and processing, which can be used on almost all known operating systems and computer platforms. This website contains lots of information about downloading, compiling, configuring, and using the program.

Avidemux and Qt vs. GTK+

In 2007, a Qt user interface has been added to Avidemux, which misled people into thinking the Qt version replaced the GTK+ one. This is not true, it has never been officially announced. Both versions are still officially a part of Avidemux. The Qt version has become the preferred one for the Microsoft Windows builds, while for Linux or BSD, there is no official preference – GNOME or Xfce users may prefer the GTK+ version, KDE 4 users may prefer the Qt GUI.
[edit]
Avidemux dependencies – MPlayer, Transcode, FFmpeg, MJPEG Tools

In general, Avidemux does not need external software for reading and writing. Some people believe it uses MEncoder, Transcode, FFmpeg or MJPEG Tools for encoding. This is completely false, even though it contains some borrowed code from these projects.

Avidemux is not an MEncoder frontend. It is not a GUI for MEncoder, it is a standalone program which uses its own code for video editing, reading and writing. The only thing these two programs have in common is that Avidemux includes several filters ported from MPlayer (like denoise3d), plus it uses libavcodec and other libraries (which are used by MPlayer/MEncoder as well as virtually any free software video program).

Avidemux does not use any external video decoders. That`s why installing any video codec (for example DivX or Xvid) in the hopes of using it for decoding in Avidemux is a wasted effort (however, Avidemux can use Xvid for encoding). Official Avidemux packages for Microsoft Windows include all external encoders (like Xvid) and decoders and other libraries, so there are no dependencies for them. In particular, as a cross-platform application, it cannot use any DirectShow or VfW decoders or encoders, which are specific to Microsoft Windows.

Avidemux does not use external FFmpeg. A built-in libavcodec library from FFmpeg (i.e. Avidemux contains its own copy of libavcodec, external FFmpeg is not used) is used for decoding and encoding of many formats.
[edit]
Software vs. format, format vs. codec

Contrary to popular myth, codec is not the same thing as format. Audio or video does not have to be decoded with the same codec it was encoded with. For example, when you encode an MP3 file with the LAME codec, it is not `LAME file, `LAME format`, `LAME audio` or just `LAME` – you don`t encode `to LAME`. It is an MP3 file and it can be decoded with other MP3 decoders, too.

However, the common practice in digital video is using these two terms interchangeably, which is caused by years of industry obfuscations, greedy proprietarism (pretending that their codec is a format is a common business model for codec vendors and a significant source of their income, as it ties the customers to their products), intentional lying in various magazines, websites etc. (in order to make it `easy` for the readers who could be "confused" by correct terms) and nonsensical use of codec FourCC in AVI (that is, codecs have their own FourCC in AVI files, so if the codec uses a common standard format, users are supposed to install multiple decoders for the same format). Historically, when a company released their own proprietary codec, it was automatically supposed to be the only existing codec for that proprietary format.

But there are standards such as MPEG-1, MPEG-2 and MPEG-4. These are specifications and developers can develop software or hardware implementations that encode or decode audio and video according to the specification. There can be multiple codecs, made by different people, using the same compression format such as MPEG-2 (used e.g. on DVDs) or MPEG-4 ASP. Codec is a software (or hardware) implementation that encodes/decodes (hence the term "codec") data to/from some format which can be compatible with other codecs that follow the same specification. Software is not a format.