Basic conversion:
ffmpeg -ss 00:00:10 -i "Skye-Model_2nd_web.mp4" -vframes 1 -q:v 2 thumbnail.jpg Sprite sheet (useful for video players): Skye-Model 2nd Video.avi
ffmpeg -i "Skye-Model 2nd Video.avi" -c:v libx264 -preset medium -crf 20 -c:a aac -b:a 160k "Skye-Model_2nd_web.mp4" If file is large and you want fast encoding: Skye-Model 2nd Video.avi