When I try to open a video in the native app I doesn't work all I see is a black screen, when I open the video using VLC it runs Ok.
What can I do?
I am also having this problem. I am totally new to Elementary OS and Linux. I can play music but not video's. I am currently looking to see if there is a codec pack that needs to be installed but am yet to find one.
A lot of proprietary codecs are not shipped with elementary os out of the box. Installing ubuntu-restricted-extras package solved this problem for me.
I also have issues with io.elementary.videos. The screen is distorted, sound appears to be just fine. I already installed the Ubuntu restricted extras (before that the screen was black and no playback happened at all). The good old MPV does the job just fine, also ss stated earlier vlc works fine.