How to Crop Videos Using Avidemux

If you need to crop a video because you only need a small area of it, you can achieve this using the free program Avidemux.

In order to get started, you will need to first open the video file in Avidemux. As cropping the video cannot use the same frame data, you will need to re-encode the video. To do this, use the drop-down box under 'Video Output' to select the format you want the encoded video to be in. You can select anything except 'Copy'. 'Mpeg4 AVC (x264)' is the recommended setting, as it is a very common codec. To crop the video, click on the 'Filters' button below that, and click on 'Crop' under 'Available Filters' on the window that pops up.

After double-clicking on 'Crop', a new window will pop up displaying the video. You can adjust the crop using the four number fields in the top left-hand corner of the window, and you can adjust these values finely using the up and down arrows. You can also click and drag the red rubber band in order to set the crop[ that way, and you can use the 'Hide Rubber Band' checkbox to hide the red lines, so you can see exactly what your crop will look like. The 'Auto Crop' button in the top right-hand corner can also be used if you want to remove black bars from your video, it works best if there is a good contrast between the video and the black bars, so you can use the timeline to scrub through the video to find a good frame. Now just click 'Ok' to set your crop. Now just save the video, and it it will encode a cropped version and export it where you want. You can also combine this with other filters as well as only export a segment of it by 

How to Trim Videos Without Re-encoding Using Avidemux

Sometimes you need to trim a long video clip to get a much smaller section, whether you recorded a much longer video and only need a shorter segment, or need a short clip from an already existing video. The problem with trimming videos using traditional video editors is that they require you to re-encode your video, meaning that it takes a long time, especially on low-end computers, and results in a lowering of video quality. Due to these reasons, it can be useful to know how to trim videos without re-encoding, which essentially just takes the data for he frames you want along with its corresponding audio and copies it into a valid video file. Doing this means that it is super quick, only taking as long as it does to read the file from disk and write your new version.

In order to trim videos in Avidemux, first you need to open the video in Avidemux. This can be done either with using the 'File' menu, or by dragging and dropping the video file onto Avidemux. Then you need to select which part of the video you want. This can be achieved by dragging the selector to the part of the video you want to have as the start of your trimmed video. The use the red-coloured button with an 'A' on it. Then, drag the slider to what you want as the end of your video, and click on the button to the right of that 'A' button, which is labelled 'B'. At this point you have selected the part of your original video to use as your trimmed clip.

To export your clip, simply go 'File' then 'Save As'. This will export your video as an .mkv file, but if you want to change the export format, you can use the drop box directly under 'Output Format' on the left-hand side to change this.