Ubuntu – What to use to quickly cut Audio/Video

ffDiaporama Movie Creator seems to be another excellent option for your needs.

From the site:

ffDiaporama is an application for creating video sequences consisting of

• titles, fixed or animated.
• images or photos, fixed or animated.
• movie clips
• music

These sequences are assembled into a slide show by means of transitions of sequence to produce complete videos

The following options are available:

• Refocusing of images and photos
• Cutting of video clips
• Notes (addition of text) for images, photos, sequences and animations
• Graphical filters on the images and the videos (conversion into black and white, dust removal, equalization of colors, etc.)
• Creation of animation by zoom, rotation or Ken Burns Effect on images or photos
• Correction of the images and the videos during animations (luminosity, contrast, gamma, colors, etc.)
• Transitions between sequences with definition of the transition type, sequence by sequence.
• Addition of a background sound (wav, mp3 or ogg) with customizable effects for volume, fade in/out and passage in pause, sequence by
  sequence.
• Generation of usable videos for most current video equipment (DVD player/smartphone, multimedia box, hard drive, etc.) but also
  publishable on the main video-sharing Websites (YouTube, Dailymotion, etc.)
• Video formats from QVGA (320×240) to Full HD (1920×1080) by way of the DVD and HD 720 formats.
• Image geometry (aspect ratio) : 4:3, 16:9 or 2.35:1 (cinema)
• Possible formats for rendering : avi, mpg, mp4, mkv

Here are a couple of screenshots from my desktop:

This is the main GUI with the timeline and all the toolbars shown.

This is the "Slide Properties" Window, on which you can define certain parameters, such as the slide duration, pan, crop and other properties. You can access this feature by double-clicking on the slide when in the timeline.

You may also wish to take a look at this answer: https://askubuntu.com/a/124848/9598 on which I explain a way to do some pro-style videos with kdenlive

Good luck!

Just use melt and instead of giving it a video file use an image file that you either join to the video at the begining or end (remember to give it an out= time in frames to define the time length of the image) or that you blend with a filter.

A lot of examples and uses of other commands too:

• Command-line video editing in Linux (cut, join and preview)

To utilize images (say, .png) in a video edit composition:

melt \
video.avi in=30 out=79 \
test.png in=0 out=15 \
video.avi in=30 out=79 \
-blank 15

Note that for test.png, in= parameter doesn't need to be 0 - however, the image will be displayed for out-in time; in this case, it would be easiest to simply leave the in=0 parameter out altogether.

The youtube playlist that you mention in your comment is really good and simple to understand. It gives good examples of the commands and also of how to write simple scripts in Bash to iterate the use of filters and mixes over multiple files. Worth watching!

Here it explains how to add to your video text using gstreamer:

gst-launch filesrc location="<Filepath>" ! textoverlay text="Title : Hello" valign=top halign=left ! xvimagesink