Possible reasons: (1) The connection uses a HDMI-to-DVI adapter. (2) The connection uses a HDMI-to-DVI cable. (3) The TV may not be set to the appropriate HDMI video input. (4) You are trying to play a MPEG2 Program Stream (PS) file. (5) The HDMI cable may be faulty. (6) Now, it’s not difficult to troubleshoot the DVD playing without sound issue.
If your DVD player plays some old DVDs, it could be the DVDs that cause the issue. Some DVDs may be region locked. You can set your DVD player to match the region. However, you have a limited number of times (usually 5) for changing the DVD player's region. Why don’t you digitize your DVDs and play them without needing a DVD player every time? It’s easy.