Table of Contents


Avidemux is a simple tool for simple video processing tasks. The keyword here is simple: it does not offer tools like a timeline, multitrack editing, you cannot freely move or splice audio and video clips from various sources. However, Avidemux allows you to do elementary things in a very straightforward way.

When you open a video file using the Open button (Ctrl+O) on the main toolbar, there are 3 basic things you can do with it in Avidemux:

  1. Cutting
    Why: For example, cutting out ads from a TV recording, or saving only a small part of a video you are interested in.
    How: Select a portion of the video with the mark A and mark B buttons, and either delete, copy, paste or save that part. If you do not reencode the video (that is, if the encoder is set to Copy), make sure all segments start with keyframes, or the resulting video will be broken at cut points. See the Cutting chapter for more details.

  2. Encoding
    Why: You may want to convert the video to a different video format that your hardware or software players understands, or you just want to compress the video to a smaller size, for archiving or publishing it on the Internet.
    How: Encoding in Avidemux means selecting an encoder that does the video compression. That is, the drop-down menu on the left cannot be set to Copy. See the Main window chapter for more details.

  3. Filtering
    Why: Basic filters applied to the picture like deinterlacing or resizing come in handy for various format conversions. Other filters may be used for adding subtitles to the picture, color correction etc.
    How: Filters require reencoding. So you have to select an encoder first, then you can add filters using the Filters button. See the Video filters chapter for more details.

When you are done with cutting, setting encoders or filters, save the resulting video file using the Save button (Ctrl+S).

In addition, there are other small features you can use, like saving or replacing the audio track from the video, joining several video files or saving a snapshot of your video.

To encode or not to encode

Avidemux works in two basic modes: copy mode and encoding mode.

Copy mode

When the audio or video encoder is set to Copy, it means no reencoding takes place, and the audio or video track from the input file is just copied to the resulting file as-is. This means it is very fast (usually a couple of minutes at most), and there is no quality loss.

Use the copy mode when:

  1. you just want to cut out parts from the video, without changing the output format
  2. you want to append several files (using either File→Append or the automatic appending that Avidemux provides) – if the resolution (width, height), video format, audio format, audio bitrate and sampling rate is the same for all files, you can use the copy mode
  3. you want to fix constant audio/video desync (using the Shift option in the audio section)
  4. you want to perform technical changes like saving the video to a different container

Encoding mode

When you select an audio or video encoder, the audio or video track is reencoded. If the compression is lossy (with most encoders it is), this implies quality loss. Encoding is also much slower than copying. Depending on the speed of your computer, it can take hours to complete.

Use the encoding mode when:

  1. you want to perform audio or video format conversion
  2. you want to compress the file to a smaller size (at the expense of quality)
  3. you have to do precise cutting that's not possible to do on keyframes
  4. you want to use filters (it is impossible to filter audio or video without reencoding it)
  5. you want to join several files with differing properties (different formats, different resolution etc.)

Basic terms

Since Avidemux is a tool that does not do things automagically for you and only executes the steps you directly tell it to perform, you should really understand what you are doing and why. Before you use Avidemux, you should understand basic characteristics of multimedia files, such as:

So, what does this all mean? Let's see a couple of use cases: