Pi4 does not show videos from HD

Yesterday I received my Pi4-4Gb. Set up (rpi4 9.1.002) went smooth and music sounds and screen is OK.But I am not able to play video files from my networked HD's. The sound is there but sounds intermittend, info about the files etc is displayed normal. It is connected through HDMI to a Sony LCD TV ( not 4k). I used to buy codecs from Pifoundation ( for my Pi's 1-3B) to make everything work correctly. These codecs are not available anymore and I also doubt that would be the reason as I have tried several file formats and nothing gives image just only (bad) sound. As I have Kodi on several Pi versions , I think I should be able to solve myself this but I am clueless.

HI,

About 40 views and nobody responses, so this is apparently not so easy. I have put the image on the card again to be sure the codecs were not missing or so, tried and tried files and video formats but no change. Now I am thinking could it be a bad cable as i can image the video format changes as soon a video file has to play. Or is maybe the Pi4 itself broken?

grael, thank you, thank you and thank you again. I feel so stupid. When I got the Pi4, two days ago I connected it to the 0 con. but nothing happened, I then switched to the other con. which gave me an image, so I assumed I did it right. I now realize that I must have been to impatient and disconnected con. 0 before it gave an image. When the Pi4 starts the screen is completely black and also as I am using CEC to switch on the screen of my Sony it takes a little while and I had just not given con. 0 enough time. Anyway, it now works great and fast.I use the first scene of the film "a History of Violence" to see if the screen goes smoothly and does not skip frames. In the scene the camera slowly goes a long the outside of a motel. The pi4 does it really nicely. thanks, That movie is a must see!