Crop Real 4K to UltraHD 4096>3840
ffmpeg -i A001_C014_01217G.4k.y4m -vf "crop=3840:2160:128:0" outputgirl.2160p.y4m
Resize to 1080p
ffmpeg -i outputgirl.2160p.y4m -vf scale=1920:-1 outputgirl.1080p.y4m
Resize to 720p
ffmpeg -i outputgirl.2160p.y4m -vf scale=1280:-1 outputgirl.720p.y4m
Convert source to YUU4MPEG2
ffmpeg -pix_fmt yuv420p -i any-source-video.webm output.y4m
Convert a sequence of images to YUU4MPEG
ffmpeg -f image2 -i "A004_C001_0122K7.00%05d.png" -pix_fmt yuv420p ouput.y4m
extract a single frame
ffmpeg -i input.avi -f image2 -ss 14.342 -vframes 1 frame.png
extract a single frame (altenative method)
ffmpeg -i input.y4m -f image2 -vf select="gte(n\, 1)" -vframes 1 frame.png
extract 1 frame after frame 100
ffmpeg -i input.y4m -f image2 -vf select="gte(n\, 100)" -vframes 1 frame.png
