There is a simple way and free way to convert video to MP3. You can do this with MP4 videos, MOV, and other video formats. VLC is a free software for Mac and PC that can extract MP3 from a video file.

You can cast content from a VLC player to your Chromecast-connected TV from a Mac or PC. As long as your devices are on the same Wi-Fi network, casting from VLC to Chromecast is a seamless process.