Black and frozen videos / images in apps (Snap, Instagram, FB, ...) I have a Blackview A10 under Android 6. Many times in a day, images are black or videos become black and frozen, thus I have to reboot my phone to be able to see it again, until it starts to become black again.
This happens in Facebook (I watch one video, then scroll to another video which becomes black and unresponsive, sometimes viewing another video unlocks this one or it neter happens), Snapchat (snaps I receive become black, with no image, for images and videos snaps) or even Instagram when someone sends me a link to a video, it stays black.

Is there a way to trace where this problem comes from and solve it, or not having to restart completely the phone every time this happens?
Maybe by restarting some service?
It's probably a defect in the device firmware. Cheaper phones often have less effort put into making sure the firmware is perfect. In that case, a new firmware would fix the problem, though again, cheaper phones are less likely to have a firmware update available and less likely to have a custom ROM development community. Even so, it's worth checking with the manufacturer.

If there are no firmware updates available, your only option is a better phone, from a manufacturer who's willing to spend the money getting the system integration right.