(ffmpeg-utils)2.4. Syntax | Video size

doc

Video size

Official documentation says:

Specify the size of the sourced video, it may be a string of the form width*x*height, or the name of a size abbreviation.

[me@host: ~]$ # The following two will have the same result:
[me@host: ~]$ ffplay -f lavfi "color=white:s=1280x720:d=3" -autoexit
[me@host: ~]$ ffplay -f lavfi "color=white:s=hd720:d=3" -autoexit

the name of a size abbreviation

96120144160200240288320350360480576
128 xsqcif
160 xqqvga
176 xqcif
240 xhqvga
320 xcgaqvga
352 xqntsc
film
ntsc-film
qpal
cif
400 xwqvga
432 xfwqvga
480 xhvga
640 xeganhdsntsc
vga
704 x4cif
4805405766007207681024108011521200
720 xntscpal
768 xspal
800 xsvga
852 xwvga
hd480
960 xqhd
1024 xxga
1280 xhd720sxga
1366 xwxga
1408 x16cif
1600 xwsxgauxga
1920 xhd1080wuxga
8581080153616001716204821602400409643204800
1998 x2kflat
2048 x2kscope2k
2kdci
qxga
2560 xwoxgaqsxga
3200 xwqsxga
3840 xuhd2160wquxga
3996 x4kflat
4096 x4kscope4k
4kdci
5120 xhsxga
6400 xwhsxga
7680 xuhd4320whuxga