The audio in the stream is ok, but no video

Maybe your Decoder/Media player does not support to decode such video codec. For exmaple, Encoder video codec is set to H.265, but your Decoder/Media player supports to decode H.264 video only.

Or, Decoder/Media player does not support such video "profile" & "Level", then please check Decoder specification. Here's an exmaple, MAG-257 box, lists these supported video codec &audio codec: