Download YouTube videos. Video formats are listed at the top of the watch page. Video links are tagged so that they can be downloaded easily.
Indeed, "f" isn't a standard suffix and judging by the code wd / ht < 1.5 ? "f" : "p" it seems like 'f' stands for fullscreen (4:3 old tv fullscreen) as opposed to widescreen (the modern standard 16:9 tv). This being said I'm not sure there's any value in "f", so I second the original question.
Yes, 'f' is a non-standard suffix. wOxxOm got it right, it means fullscreen. The intention is to tell quickly if a video is 4:3 or 16:9. I could have used 480ws to denote widescreen, but I think it is clunky and widescreen is the default these days.
I use 144v and 240v for two reasons: (i) I'm not interested whether they are full or wide, (ii) they appear in both full and wide! That is, you will see both 144p and 144f (at least for some videos?). Since it looks out of place without a suffix, I just append 'v' for vertical. :-D
Ah, that makes enough sense I suppose. I'm just not used to seeing those suffixes before so I was a bit confused. Thanks for explaining.
Difference between 480p and 480f?
I've looked around on Google a bit to figure out what the difference is but I couldn't find anything. I've heard of i and p as a proper suffix but never f before. (Also somewhat related but I just realized that 240 and 144 have a v as well, what does that mean too?)