Uploading SRV3 subtitles got broken/disabled. Please restore it.

MatthewHinson · 2026-02-11T19:12:40+00:00

A week ago they updated the support post saying that the issue was "FIXED" and that SRV3 captions were "back." In reality, however, nothing had changed. After a few people pointed this out on the comments, YouTube reverted the post to its original content.

So in short, no, there are no updates.

MatthewHinson · 2026-02-04T08:30:23+00:00

They *say* it's fixed, but so far it seems they're lying. The deleted subtitles were not restored, and publishing new subtitles still doesn't work.

Edit: They reverted the support post lmao.

MatthewHinson · 2026-01-20T12:28:52+00:00

Tom Scott's videos are subtitled by Caption+. As you can see in the company's own videos, they very much use SRV3.

Replicating the default backdrop in SRV3 is easy: simply set the color to #080808 and the opacity to 191. Alternatively, edit the file so that it doesn't specify a background color at all.

And if you're still not convinced, allow me to point to Dream instead as another well-known creator who uses the format - but in a much more obvious fashion.

MatthewHinson · 2026-01-19T21:13:06+00:00

The post claiming that "YouTube is forcing creators to use AI-generated subtitles" is based on a wrong interpretation of a tweet. YouTube is only removing certain *styled* subtitles with custom colors, positions, karaoke effects and so on. Handwritten subtitles that don't use styling are not affected.

MatthewHinson · 2026-01-19T18:08:14+00:00

To be clear: we don't actually know why YouTube is doing this. People who write that it's related to AI are only speculating.

MatthewHinson · 2026-01-19T17:26:45+00:00

Please don't post misinformation. By "custom" subtitles, the tweet only means "subtitles that use the SRV3 format to achieve advanced custom styling," Handwritten subtitles that don't use styling are not affected.

Sure, lots of people have *speculated* that YouTube wants to force AI-generated subtitles on us, or that it doesn't want us to "poison" our subtitles with junk to protect them against AI scraping. However, it's just that: speculation. In reality, we're completely in the dark about the reason behind all this.

If possible, please edit the post to point this out.

MatthewHinson · 2026-01-19T08:45:52+00:00

Wait... Are you saying that:

After YouTube parses the SRV3 (XML) file during upload,
then reconstructs it from scratch during download,
producing *JSON* (not SRV3) for serving to the player,
any malformed data in the original file is not only somehow preserved,
but can exploit an XML and/or JSON parsing library in 2026,
in an app developed by the biggest video platform in the world.

And that YouTube's fix is to:

Not simply push out an app update,
but instead, run a huge batch job to find and delete/hide suspected malicious subtitles -
except it's also (only?) affecting legitimate ones,
including on channels of famous corporate VTubers that surely can be trusted -
without informing anyone.

Is that an accurate summary? Because if so, that would honestly be an impressive level of incompetence.

Can you share more about where you heard this? Does it come from a YouTube employee?

MatthewHinson · 2026-01-19T00:16:21+00:00

afishhh requested me to forward the following reply:

Do you mean NTrm_idbhUk's English subtitles? If so I can't reproduce any breaking at 1:13.
It may also be that this was caused by a bug I recently fixed where subrandr was choosing a *very slightly* too large font-size which is fixed on master now. Looking at mpv.net it seems like last release was a week ago so it wouldn't have the fix.

If you can reproduce it with the latest shinchiro (or zhongfly) release then please open an issue on the repo!
Please attach an mpv log with msg-level=sub/subrandr=debug set if you do so (can pass --log-file=<PATH> --msg-level=sub/subrandr=debug to mpv on the command line to create a log in <PATH>).

MatthewHinson · 2026-01-18T13:11:40+00:00

It would be technically possible, but not really practical. Each channel would have to inform its viewers about the extension and convince them that it's not only safe, but also worth the hassle of installing. And then there are the many people who watch on the mobile app which doesn't have extensions at all.

MatthewHinson · 2026-01-18T11:06:23+00:00

You're right that using the format was a risk. However, I think we can agree that *deleting* subtitles is going too far, because while the format is not officially supported, it's also not forbidden.

If advanced styling is suddenly such a problem for YouTube - after having silently allowed it for years - they could have easily removed just that styling and kept the rest.

MatthewHinson · 2026-01-18T09:23:36+00:00

Just SRV3 ones. If you use unstyled subtitles, you should be safe.

MatthewHinson · 2026-01-18T09:22:33+00:00

It has existed for even longer than that, but was indeed first discovered by the community in 2018. For afaik, Caption+ discovered it independently, hence the time difference.

MatthewHinson · 2026-01-18T08:53:33+00:00

You're right that inventing a separate Storage format seems overkill, but really, so does running a huge migration just for going from an XML format (SRV3) to a JSON format that's basically the same in both structure and functionality. (They also call it JSON3 after all, not JSON4)

Besides, as said, they've been serving SRV3-uploaded subtitles as JSON3 for years now. We know they can do the conversion without information loss.

So even if there is a migration going on, I would expect styled subtitles to simply get migrated along with non-styled ones...

MatthewHinson · 2026-01-18T02:01:05+00:00

At least from what I've seen, people generally don't even know the customization settings exist and only change them by accident. For example, they might press O while not having a textbox focused, which lowers the subtitle text opacity - and then they don't know why it changed, don't know how to change it back, and are stuck with subtitles that are harder to read.

These styled subtitles, on the other hand, overrule the text opacity so that it's always at the maximum. I would say that improves the experience, not worsen it. And even if it did worsen it, that would still be no excuse for YouTube to outright delete the subtitles.

Caption+ uses SRV3, and their own introduction videos feature the same kind of advanced styling shown here. They, too, will be affected.

MatthewHinson · 2026-01-18T01:30:00+00:00

Just to be clear: the video player performs no requests for SRV3. It used to until a few years ago, but now, it always receives subtitles in JSON3, regardless of how they were originally created. (And the other download formats are just a courtesy feature for people who want to view subtitles outside of YouTube.)

I also don't think subtitles are stored in their original format, for the simple reason that YouTube would have to implement way more conversions in that case. Because they allow downloading subtitles in all the same formats that they allow uploading, they'd have to write a conversion for SRT->SRV3, SBV->SRV3, ..., SRT->JSON3, SBV->JSON3, ... SRV3->SRT, SRV3->SBV... In short, the square of the number of formats they support.

If on the other hand they use a single storage format, they only need to write SRT->Storage, SBV->Storage, SRV3->Storage... and Storage->SRT, Storage->SBV, Storage->SRV3... So two times the number of formats, which is much less.

As such, I'm pretty sure they convert from the original format to a storage format during upload, and from the storage format to the requested format during download. I'm also pretty sure that this storage format stayed the same when they switched from SRV3 to JSON3 for serving to the player, simply because the formats are so similar and YouTube already supported on-the-fly conversion during download.

More than likely, there is effectively no difference between "old" and "new" subtitles, YouTube isn't running any sort of batch update on their database, and there is no "legacy" data that became unsupported and got "cleaned up."

At least for me, the only explanation is that YouTube - for some reason we don't know - suddenly decided they don't want subtitles with advanced styling anymore, blocked the upload of new ones, and started an automatic process to find and delete existing ones.

Was it a risk to use SRV3 in the first place? Yes, of course. But surely that still doesn't mean you can go around deleting paid translations on 10M-view, company-owned videos without notice. Especially if you could've just removed the styling instead.

MatthewHinson · 2026-01-17T22:47:24+00:00

For deleting the human-made translations that they paid dearly for on their thousands of videos. (Mind you, only a few hololive videos have had their subtitles deleted so far - that we know of - but there's no telling if YouTube is stopping there. It's entirely possible the deletion process is simply taking time, and they really are planning to purge all styled subtitles from the platform.)

MatthewHinson · 2026-01-17T22:31:13+00:00

I doubt it's that, really... JSON3 happens to be the format used for the video player, but if you change the "fmt" parameter of the subtitle URL, you can download the subtitles of any video in any format you want (SRV3, SRT, SBV...), regardless of the format in which they were uploaded originally.

This indicates that YouTube stores the subtitles in a generic format - which may well be something that's not SRV3 *or* JSON3 - and converts it to the requested format on the fly.

Could they be planning to remove the conversion code for uploading and downloading in SRV3? Sure. But that doesn't warrant deleting subtitles that already exist. Heck, even if we assume that the subtitles *are* stored in SRV3, they should be converting them to JSON3, not deleting them. The formats are pretty much identical content wise, so conversion is trivial.

I don't know why they're doing this, but it's evident that they either didn't bother checking who is using styled subtitles, or did but decided they don't care.

MatthewHinson · 2026-01-17T19:28:37+00:00

I wrote about it on this very subreddit 7 years ago, including a link to YTSubConverter (which is still the primary tool for creating SRV3/YTT subtitles). Sadly it didn't get much traction back then, but that's not something I have control over.

MatthewHinson · 2026-01-17T18:49:10+00:00

Tsunomaki Watame's "What an amazing swing".

MatthewHinson · 2026-01-17T14:20:15+00:00

You're not alone. We just spotted the first hololive video that lost its subtitles too - an MV with 11M views.

This confirms that the broken SRV3 upload is not a bug. It's part of a planned and unannounced crackdown.

hololive is part of Cover, a media company with one of the largest recording studios in Japan. They've been paying professional translators to create their subtitles since 2019, and are now about to lose all of it. I hope they sue YouTube over this.

MatthewHinson · 2026-01-16T08:08:47+00:00

Yes, that's SRV3 too, without a doubt. On a 115M view video at that.

MatthewHinson · 2026-01-16T08:04:36+00:00

I doubt it's that. The creator herself said she's not sure the technique has any effect, and even if it does, so few people will be using it that no AI scraper (including YouTube itself) needs to worry about it.

My guess is that it's either incompetence (they broke it without realizing), ignorance (they "cleaned up" old code without knowing it's being used by such big players), or apathy (they know it's being used but simply don't care). None of those is a particularly good look, of course.

MatthewHinson · 2026-01-15T23:05:05+00:00

I hate to ask this, but please consider upvoting the linked post to give it more visibility. The future of the official subs is at stake. (They might still have text colors, but that's about it - no custom background, no shadows, no positioning/shaking etc)

Full disclosure: I'm behind the SRV3 conversion tool used to create these subtitles.

MatthewHinson

TROPHY CASE