What method to view focal length of lens used in a video clip ?

[DBenz]

Hi, I am using a Sony AX100E 4K camcorder, has a zoom lens as do most camcorders. It also has a photoshoot option/button.
shooting on the full W setting, rocker switch held down at W end, my image viewing prog BreezeBrowser shows me it was 9mm.
I shot hundreds of 4K vids at the weekend at a show, then captured stills from them with VLC.
I put them into my Photogrammetry prog Agisoft, and got 3D models out. all was good.
then today I use the stills from a vid of another item at the show, and Agisoft Metashape rejects half of the stills.
Maybe the focal length differed. all shots in a 'chunk' (sequence using a set of photos) must be SAME FOCAL LENGTH, a golden rule.
I use MediaInfo prog and tree mode pn one of the video .mp4 files, but it has no data on the focal length !
Sony Play Movies Home on the camcorder and on the PC, generates a .MP4.modd file for each .mp4 video file, and sometimes there is also an .mp4.moff.
These I am told hold the exif data for the .mp4, so dont lose them !
How can I find out what I had used, had it crept away from the W setting, maybe 8.5mm for example.
I was however being very careful to keep pressing W between the vids.

I then fed the rejected stills into a new project in Agisoft metashape and all were aligned,. so that set must differ from the rest of the set. A very neat dividing line between aligned and not aligned, compared to the often scattered failures.
I also tried Photoscan, which rarely fails whilst Metashape fails a few, and it also rejected them, in fact a few more that were accepted by metashape.

I asked Sony but got nowhere.

DBenz

[Sharc]

Did you try ExifTools?
https://exiftool.org/
I have some doubts whether the camara focal length is kept in .mp4 container. Worth a test though.

Edit:
I would suggest to contact the author. There has been a similar discussion in his forum:
https://exiftool.org/forum/index.php?topic=17345.0