Using ffmpeg to get the actual video resolution
In yuv420p, 1280x720 [SAR 1:1 DAR 16:9],

yuv420p indicates the pixel format and chroma subsampling scheme.

the video's raster resolution is simply 1280x720.

the video's Sample Aspect Ratio (width of pixel : height of pixel ratio) is 1:1 (square pixels)

the video's Display Aspect Ratio is 16:9