WebM Tutorial

https://gist.github.com/ndarville/10010916

http://boards.4chan.org/gif/res/6197000#p6198010
Download ffmpeg from https://www.ffmpeg.org/download.html and extracting the file (might need 7zip).

Then go into the folder, shift+right click on "bin" and select "open console here." A little command line prompt will appear.

Then copy THIS into notepad:
ffmpeg -i your_video.mkv -ss 00:00:10.000 -to 00:00:20.000 -c:v libvpx -crf 4 -b:v 1500K -vf scale=640:-1 -an output.webm

"your_video.mkv" is the video you want to use. More on that later.

The first numbers are your start time in hh:mm:ss and the second numbers are your end time. That's set from the 10 second mark to the 20 second mark.

(WRONG) 1500K is the max bitrate (quality) 4chan accepts. Lower that for smaller sizes.

scale=640 is the width of the finished video. Change it to whatever you want or looks good to you. The lower the bitrate, the lower you probably want your final width. Height is found automatically.

output.webm is the name of the final video, change it to whatever but keep ".webm" at the end.

Once you're ready, copy that line and paste it into the command prompt by just right clicking in the black area where it wants you to type.

IMPORTANT: It will look for your video file in the bin folder, and put the output file there too. So either move your file to the bin folder or get the full path like this "C:\Users\Jack\My Videos\Jack's Blue Balls Vids\Massive tease AAA full stars would fap again.mp4"

Basically wherever the video is located, followed by the video name. Enclose it with quotations and put it where "your_video.mkv" is. So for me, the final thing would be this:

ffmpeg -i "C:\Users\Jack\My Videos\Jack's Blue Balls Vids\Massive tease AAA full stars would fap again.mp4" -ss 00:00:10.000 -to 00:00:20.000 -c:v libvpx -crf 4 -b:v 1500K -vf scale=640:-1 -an output.webm