https://universaldesign.ie/communications-digital/web-and-mobile-accessibility/web-accessibility-techniques/design-accessible-digital-content-introduction-and-index/ensure-images-video-and-audio-are-accessible-to-everyone/provide-alternatives-for-images-video-and-audio-content/pr-2
Provide text equivalents for audio-only and audio content in video - Centre for Excellence in...
for audio only