Are there any apps to resize videos in Ubuntu?

I have a 20-min video that my friend has recently recorded, but the whole thing occupies 1 G. Is there a way to reduce it to something that can be emailed to people without completely using the quality?

Terminal commands (Which by default are not installed) are:

MENCODER

Install it by sudo apt-get install mencoder

mencoder

The part about mencoder that you want is the parameter -vop scale which tells mencoder to what scale you want the video to go to. This is normal if you want to reduce bandwidth use, lower video size, etc..

mencoder input.mp4 -ovc lavc -lavcopts vcodec=mp4 -vop scale=640:480 -oac copy -o output.mp4

or

mencoder input.mp4 -ovc lavc -lavcopts vcodec=mp4 -vf scale=640:480 -oac copy -o output.mp4

or a simple

mencoder input.mp4 -vop scale=640:480 -o output.mp4

Although from my experience is better to include additional information for video and audio like the one above.

FFMPEG (Deprecated)

Install it by sudo apt-get install ffmpeg

ffmpeg

Here is an example of ffmpeg:

ffmpeg -i input -vf scale=iw/2:-1 output

Where IW = Video Input Width.

Scale = Parameter to scale to. In this case you are dividing the original size by 2 (iw/2)

both of which can provide more information if you either execute them without parameters or variables like just mencoder or ffmpeg or type for example man mencoder or man ffmpeg which will give you a VERY extensive little manual on how to work with them.

AVCONV <-- I love this guy!

avconv

To Install - sudo apt-get install libav-tools

To Run - avconv -i input.mp4 -s 640x480 output.mp4

Where -i is for the original input file, -s is for the size for each frame and the name of the output final goes in the end.

GUI tools which I love are:

AVIDEMUX - It can resize and lower the size which helps in cases where the objective is to lower size. avidemux

HANDBRAKE - Excellent tool for converting videos and optimizing size. I use it a lot when going from ogg to mp4 with h.264. Lowers A LOT the size. handbrake

OPENSHOT & PITIVI - Both are good video editors tha can help lower size when rendering the video. openshot and pitivi

So in conclusion, for direct resizing/scaling you can use the terminal ones. For size you can use all.

Generally for such tasks, you could try Handbrake

HandBrake is a tool for converting video from nearly any format to a selection of modern, widely supported codecs

It should be in the repositories.

sudo apt-get install handbrake

Though 1GB ---> something that can be send by e-mail, sounds rather (read extremely) optimistic.