How to find out if a *.mp4 video is taken in 720p or 1080p mode?

[pxstein]

Assume I got a *mp4 video file originally captured by a smartphone.

How can I now (later) find out if the video was taken in 720p or in 1080p mode?

Does 720p ALWAYS have a resolution of 1280x720
and
does 1080p ALWAYS have a resolution of 1920x1080

?

[jan5678]

use mediainfo, it will tell you what you want to know

[nicholasserra]

Or open in VLC and look at codec info.

[Alwyn]

Does 720p ALWAYS have a resolution of 1280x720
and
does 1080p ALWAYS have a resolution of 1920x1080

Nobody's answered yet so here's my two-bob's worth.

Yes, normally. My understanding is that there is only one "standard" resolution for, say, 720P, which is 1280x720. There is no "normal" 1440x720P. Your phone would only take "standard" resolution video eg 1280x720, 1920x1080.

The second number denotes the "name" of the resolution eg 720, 1080. The P or I denotes whether the file is Progressive or Interlaced.

However, your video editor may well be able to create any resolution. For example, for Facebook, you could make a video that was 1000x1000P.

[davexnet]

There is ambiguity in the question. Is the OP implying that
the video was altered from the original capture? Too little context.