png-sequence -> mp4 command line

[harold]

Here is the command line I am currently using to do png seqence -> mp4 conversion:

ffmpeg -framerate 60 -i ./out-%03d.png -r 60 -c:v libx264 -pix_fmt yuv420p out.mp4

Note, this depends on a certain file naming convention --- learning about -i on ffmpeg may help adapt to different scenarios.