Video Contact Sheet *NIX or vcs for short, is a script that creates a contact sheet (preview) from videos by taking still captures distributed over the length of the video.
The output image contains useful information on the video such as codecs, file size, screen size, frame rate, and length.
Notes:
Using -i or -n with values that lead to the same number of vidcaps doesn't necessarily yield exactly the same vidcaps, you'll have to play with them for best results.
Example: With a video that lasts for 22min 14secs, -n 6 will create the six vidcaps:
3:22, 6:44, 10:04, 13:28, 16:50 and 20:12, while -i 3m will create
3:00, 6:00, 9:00, 12:00, 15:00 and 18:00.
As you can see, -n distributes the vidcaps all over the video while -i N starts at N and goes in increments of it up to the end.
You can set the aspect ratio of the video with -a. It is only required for anamorphic material and discouraged for the rest.
It can take either a floating point number (like 1.33 or 1.778) or a fraction (like 4/3 or 16/9). The latter is slightly preferable.