video_convert.jl

using FFMPEG
function save(src::String, out::String;
              framerate::Int = 24, compression = 20)
    typ = splitext(out)[2]
    mktempdir() do dir
        if typ == ".mp4"
            ffmpeg_exe(`-i $(src) -crf $compression -c:v libx264 -preset slow -r $framerate -pix_fmt yuv420p -c:a libvo_aacenc -b:a 128k -y $out`)
        elseif typ == ".webm"
            ffmpeg_exe(`-i $(src) -crf $compression -c:v libvpx-vp9 -threads 16 -b:v 2000k -c:a libvorbis -threads 16 -r $framerate -vf scale=iw:ih -y $out`)
        elseif typ == ".gif"
            filters = "fps=$framerate,scale=iw:ih:flags=lanczos"
            palette_path = dirname(src)
            pname = joinpath(palette_path, "palette.bmp")
            isfile(pname) && rm(pname, force = true)
            ffmpeg_exe(`-i $(src) -vf "$filters,palettegen" -y $pname`)
            ffmpeg_exe(`-i $(src) -c:a aac -i $pname -lavfi "$filters [x]; [x][1:v] paletteuse" -y $out`)
            rm(pname, force = true)
        else
            error("Video type $typ not known")
        end
    end
    return out
end