All I see here on the forum is people telling all that they have sound and no video. All the answers seem to be the same, what is your model? what is your id number?
These are questions, not answers. What is the answer to fix this problem? Since many people have this problem, it needs attention. Questioning how they have their Roku's set up or their router settings is still a question, not an answer; and the one answer that I did see did not fix the problem.
The Roku works fine for 20 minutes and then the video stops, but the sound continues. Rebooting, making sure of video settings that jive with the 4k tv set, setting the hdr or the chroma makes no difference; making sure that the tv set's input is set to "enhance" does not solve the problem.
I have several customers that I sold Roku to and they all complain about this very issue. This all started about 6 months ago; before that, everything was normal. (this usually indicates a firmware issue) So what is the fix?