Damn, I was reading this thread last week and then I couldn't find it when I posted over in the "Pluto Holiday Channels added" thread.
Anyhow, here's my tidbit from there that I really meant to post here: Pluto Holiday Channels added - #15 by jkr4m3r
It may be a good time to inquire as to if there has been any further development in making CC for Pluto happen. There have been changes to Channels and the clients over the past few months which I believe may be positive in implementing this feature (as referenced in a question I asked not to long ago).
Has there been anymore progress on getting this to work. I have been despratelty trying to get CC working on Pluto. Lately I have been experimenting with the HDMI for Channels to try to pull in channels from the Pluto app with unimpressive results getting some OSD that wont go away and getting the channels tuned in. I have also dabbled with the BETA: Chrome Capture for Channels which is too experimental to work with Pluto (but its less than a day old so keeping my flingers crossed).
Would love to see this working in ChannelsDVR tried and true Pluto methods.
Channels newbie/non-technie here. I just implemented the Pluto channels nocords solution and it's amazing. Couldn't figure out how to turn on CC so came to see what I was doing wrong, and--there is no CC! Unfortunately, with hearing issues here it's a must. With TVE gradually/suddenly going away, the huge variety of Pluto channels would've gone a long way toward mitigating its loss. But when something seems too good to be true it often is. Whether it's a matter of resources/time or a complete impossibility IDK, but I'd still like to add a belated vote to the search for a solution. Thanks.
A few of the Pluto channels do have closed captions, but yeah it sucks. Here’s a list I put together of sources that have captions. Some of the Pluto channels are on these other services that have captions. Worth trying out 
As I recall, they work fine on the Pluto app.
Thanks for linking your list--what a great resource! Will check it out. I see that Pluto direct does have CC. But there's a world of difference between suffering thru tons of non-skippable ads and a chaotic interface vs the ability to organize and record from the fantastic Channels guide. It's a premium solution but missing one crucial element. On the other hand, Channels implementation of TVE with CC is fantastic. With the channel list shrinking, the hope is there will soon be alternatives that include standard CC support.
I did some searching, can't find the post, but some months back a user posted here about a solution they cobbled together with some 3rd party voice recognition / AI tools that could generate closed captions on-the-fly for content that didn't have them natively available in Channels DVR. I though that was pretty cool!
Sorry I didn't follow this up in this thread, but I did manage to get Pluto with CC working through the ADBTuner route. Of course that is a fairly big project just to get CC, but since I already was using ADBTuner for other things, it turned out great for my Pluto CC problems. As far as the OSD problem I was having, it was related to an optimization issue that not everyone would encounter. The solution to that is below.
By chance, have you ever tried it with Chrome Capture? I am curious if Puppeteer passes along caption data in a format Channels can ingest. Unfortunately I couldn’t get it to run on my server.
Sigh,
Yes, this would be awesome if only all Pluto captions were supported.
Yes, I don’t have the skills to figure it out myself, but I would be happy to support the effort monetarily.
OK,
With Claude Code I was able to figure out how to burn in the webvtt captions before they get to channels. So let me know if this works or if it doesn't work and I'll do my best to help make it work for more people.
https://hub.docker.com/r/kjoyce77/hls-subtitle-proxy
I tested it via pluto-for-channels and also the nocords direct file when it used to work.
Well I don't think channels without subs are working and some channels I am getting that do have subs are also not working. So please just let me know what works and doesn't if you can and I'll see what I can fix next weekend.
edit: added public link
The link is behind a login
makes me wonder if a solution similar to this would work for ah4c & adbtuner
Thanks, yeah, first time publishing something on Docker Hub.
It is a proxy so the downstream just sees streaming links that have burned-in captions. So it should work with anything picking up IPTV streams like this... At least eventually. I did most testing through VLC and iTunes.
We've just shipped support for WebVTT in the latest DVR pre-release: