James Cridland, writing on Medium, examines the challenges of providing podcast captions:
The Jones vs Gimlet suit isn’t asking for transcripts. Instead, it’s requiring Gimlet to produce closed-captions.
While almost any podcast app will offer a link to a transcript, with the drawbacks that I outlined above, there isn’t a single podcast app that I’m aware of that natively supports closed-captions for podcasts. Neither are closed-captions written into the RSS specification.
Closed-captions are also timing-specific. Google did get a prototype of closed-captions working on the Google Podcasts app last year, but didn’t launch it. One of the main issues, one of the team told me over a coffee, was that pre-prepared closed-captions didn’t work with dynamically-inserted ads. If you’d been served a 40-second ad about mattresses while the closed-caption generator had been served a 25-second ad about a VPN, then all the closed-captions after that point would be misaligned with the audio.