I’ve run into similar issues trying to extract audio from my TV’s HDMI output, and it wasn’t as straightforward as I expected. Ended up getting an HDMI-ARC extractor, but like others mentioned, I had to tweak my TV’s settings to make it work properly. Some extractors don’t support volume control, so double-checking specs is key.
Speaking of conversions, I also deal with video format issues from time to time. When I needed to convert some media files into AMV format, I found this AMV converter pretty useful: https://www.movavi.com/video-converter/amv-converter.html.