using ffmpeg to adjust perspective

Thank you for the music: Imperial Forces by Aaron Kenny changing the perspective of a video (Stretching or squashing a video based on a quadrilateral shape you define to give the appearance of perspective) if you imagine plotting 4 sets of x,y coordinates on a video and drawing lines from one corner to the other to make a quadrilateral shape and then you stretch the area of this quadrilateral shape to fit the shape of the original video that is what this command does. ffmpeg -i input.MOV -vf "perspective=0:0:W:400:0:H:W:H-400" perspective0.MOV this first command selects a quadralateral shape the first 2 coordinates x0 and y0 which is shown as 0:0 0 for x0 coordinate means that the upper left corner moves to the right 0 pixels (it doesn&move that point) 0 for y0 coordinate means that the upper left corner moves down 0 pixels (it also doesn&move) W:400 represents the top righ corner coordinates x1:y1 W for x1 coordinate means the coordinate for the top right corner is the same number of pixels accross as the width of the video 400 for y1 coordinate means the coordinate for the top right corner is moved down 400 pixels 0:H are the coordinates for the bottom left corner x2:y2 (H represents height in pixels of the video) W:H-400 are the coordinates for the bottom right corner x3:y3 If you want the original image squashed to fit into the quadrilateral shape then you add the sense=destination option ffmpeg -i input.MOV -vf...