Change FFmpeg minimum version to 2.4
Change FFmpeg minimum version to 2.4

j-b-m/mlt,j-b-m/mlt,j-b-m/mlt,mltframework/mlt,mltframework/mlt,mltframework/mlt,mltframework/mlt,j-b-m/mlt,j-b-m/mlt,mltframework/mlt,j-b-m/mlt,mltframework/mlt,j-b-m/mlt,j-b-m/mlt,j-b-m/mlt,mltframework/mlt,j-b-m/mlt,mltframework/mlt,mltframework/mlt,mltframework/mlt