If you would like to scale your video using FFMPEG you can do this by Just using
From the FFMPEG scale filter documentation:
If one of the values is
n > 1, the scale filter will also use a value that maintains the aspect ratio of the input image, calculated from the other specified dimension. After that it will, however, make sure that the calculated dimension is divisible by
nand adjust the value if necessary.
Set width to 1280, and height will automatically be calculated to preserve the aspect ratio, and the height will be divisible by 2:
Same as above, but with a declared height instead; leaving width to be dealt with by the filter:
“divisible by 2”
As required by x264, the “divisible by 2 for width and height” is needed for YUV 4:2:0 chroma subsampled outputs. 4:2:2 would need “divisible by 2 for width”, and 4:4:4 does not have these restrictions. However, most non-FFmpeg based players can only properly decode 4:2:0, so that is why you often see
ffmpeg commands with the
-pix_fmt yuv420p option when outputting H.264 video.
Unfortunately you can’t use
-2 for both width and height, but if you already specified one dimension then using
-2 is a simple solution.