Question Videos won't play after transfer to SD card

[willy_sparrow]

Android 12 Galaxy S10e.
I took several screen recordings using the native function.
Moved many to sd card using "files by google" app. moved them separately in groups of 1-3)
Some of them are playable, some are not. as pictured, the ones with blank thumbnails are unplayable.
they are unplayable with both native video player, and EX file manager
the files still show the full sizes (1+GB),
with EX file manager I could see that they were 0 mins long in the file info.
Worth noting that sd card is 99% full now.
Also worth noting that a couple of the files wouldn't transfer due to limited space, so I had to make more space, then they transferred, and I remember at least one of the specific files that I had to reattempt is definitely playable after transfer.

What can be done?

Edit: wording

 

[B. Diddy]

Welcome to Android Central! How much total storage does the card have (or claim to have)? The larger the supposed size and the cheaper it was, the more chance that the card is counterfeit (meaning the seller took a smaller card and programmed it to report much higher size). The problem with counterfeit cards is that if you unwittingly exceed the actual storage space, data starts to get corrupt.
See this: How to Spot a Fake MicroSD Card and Avoid Being Scammed

 

[VidJunky]

Welcome to Android Central forums. Just a few questions before attempting to offer advice.

You've looked at the file size in the Files app, but did you by chance take a look at the file type?

Do these items only live your SD now or do you still have the original files? If you have the originals, do those play OK? Are the same originals damaged as copied files?

I'm assuming, because you really didn't say specifically, that you are trying to play these on the phone, have you tried playing them anywhere else? On a PC, a Laptop, or tablet?

My first inclination is that the files might be damaged but two things about that. First the placeholder for damaged media usually have a broken symbol and your files don't have this broken feature, and when broken they can show weird file sizes but often don't show a size at all. Which brings me to my question about file type. I'm wondering if when transferring these files, if the file type may have become damaged. What I mean is, let's say these are .3GP files, do they still have all three file type initials. So instead of .3GP it might say .3G_ or .3_ _. Something like that. If the file type got damaged you can actually edit the name of the file and add the missing part of the title.

Still looking at file type, you can actually change the file type the same way you would repair a title by picking the rename option. Perhaps try changing the file type to something like .MP4, .3GP, or .AVI, and see if they play with a new file extension.

I would also be curious to know if they play on another device?

Let us know what you find and we will offer more advice.