Did you know that DVDs have two very different kinds of captioning data stored on them?
If you didn’t, don’t feel bad because it turns out a whole lot of folks in charge of making things which play DVDs
forgot about that second one and in 2025 they largely no longer work (or at least not without some pretty big headaches).
Take a look at this.
I have this Blu-ray disc player from 2009 connected to this TV over an HDMI connection.
Like most Blu-ray players it will also play DVDs,
and it wears the DVD-Video compatibility mark to assure us it supports all of DVD’s features.
Like subtitles.
And if I press the subtitle button on its remote, they appear.
In fact I’ve got several choices of subtitles available,
including a few different languages and a second set of English subtitles for the filmmaker commentary track.
Yeah, remember those?
Physical media had perks!
But now, take a look at this.
This is a box set of Perry Mason DVDs which I purchased because, if it wasn’t obvious enough,
I am an old soul.
And like most DVD packaging, it contains a basic overview of the technical details and features of the discs.
Right here we see the classic “closed captioning” CC mark which indicates these discs contain English captions.
Yet when I play these discs in this Blu-ray player and hit the subtitle button on its remote…
nothing happens.
The Blu-ray player simply ignores that button as if it’s completely unaware of the fact that these discs contain closed captioning.
Except, and here’s what’s weird about this situation,
it knows they’re there and is correctly decoding them.
In fact it’s doing it right now.
See, HDMI was still relatively newfangled in 2009 so this Blu-ray player sports analog video outputs.
Including basic composite video.
As luck would have it, this cheap Walmart TV happens to have a composite video input and if I switch over to that…
well there they are.
And they’re fantastic captions - word-for-word perfect plus they’re making excellent use of positioning to help indicate which character is speaking
(a feature, by the way, which is still missing from YouTube’s native captioning tool).
Really wish they’d spend a little more time making that better and easier to use.
Anyway, since we can see the captions on the composite input,
why does the Blu-ray player behave as if there are no subtitles on these discs?
Well that’s because there are no subtitles on these discs.
But there are closed captions.
And the Blu-ray player is actually handling them exactly as a DVD player should.
The only problem is it will never show them to us.
See, these captions? They’re not part of the image.
In fact they’re being generated by this TV from a stream of text data which was extracted from the disc by the Blu-ray player
and then snuck into a non-visible portion of the analog video signal coming out of that jack and only that jack.
Which means if you’re living in 2025 and using the HDMI or even the component output,
these captions simply do not work.
This might seem pretty ridiculous, but DVD is an old format which was designed to behave in some old-fashioned ways.
Which leads me to some distressing news:
next year, the DVD will turn 30.
Yep. Don’t like it but it’s true.
And when it first hit the scene in 1996, the world was still very analog.
Consumer television sets (even really high-end ones) didn’t have digital video inputs,
and cheaper TVs didn’t even have composite inputs - necessitating the use of an RF modulator like this one if you wanted to hook up the Playstation.
That is if you didn’t run it through the VCR which would have one of those built-in.
But anyway, because of this reality DVD was in many respects a bridge technology.
Outside of satellite television and a few exotic camcorders, it was the first way to get broadcast-quality digital video in the home.
But, since nobody had digital TV sets, DVD players needed to convert the digital video data stored on the disc into the analog video signal that a television expects.
And here in the United States, one of the things a TV in 1996 expected to see in that analog video signal is closed captioning data.
If it was there, and the user wanted them, the TV would display the captions.
This tech is much older than the DVD, and had become fairly well established by the time DVD hit the market -
in fact television sets were required to support closed captioning in 1993,
and caption decoders for over-the-air television broadcasts had been commercially available since 1980.
How does it work? I’ll happily show you,
but I made a video about this technology and its history back in 2018, so I’ll only provide a very basic overview here.
If you’d like to learn more - clicky thing.
In brief, analog television worked by very quickly and repeatedly scanning an electron beam across the face of a cathode-ray tube
in order to produce a whole bunch of glowing horizontal lines.
That pattern of lines is known as a raster, and an image could be produced by varying the brightness (and color) of those lines as they were drawn.
Oldfangled television receivers generate their own raster locally,
so we needed a way to synchronize incoming video signals to the local circuitry in the television so the transmitted images could be assembled correctly and appear stable.
This was done by periodically cutting the signal to zero which would reset the television’s scanning beam and synchronize its raster with the incoming signal.
We called these periods of zero intensity blanking intervals,
and the vertical blanking interval signaled the start of each individual video image by zeroing out the signal for 20 or so video lines.
Now in ye-old days, the image on the screen literally was the video signal,
which means the electron guns at the back of the picture tube which actually draw the images also drew those synchronization signals -
and they would appear as black bars.
But television receivers were set up to deliberately stretch the image slightly beyond the edges of the screen.
This was known as overscan and it made sure the image filled the entire screen and that the blanking intervals weren’t visible.
Now, there was never anything in the blanking interval - it’s blank.
But we eventually realized that we didn’t need quite as many lines to be blank as we thought.
We could actually stick a little something extra in one of those blank lines and a TV receiver would still synchronize with the incoming signal just fine.
So line 21 took on a new role: in 1976 it officially stopped being the end of the vertical blanking interval and instead became a data stream.
This is what it looks like.
In this recycled footage I’ve messed with the controls on this black-and-white TV to shrink the height of the image
which allows us to see the normally-obscured vertical blanking interval.
And in the last video line before the image starts,
we see a set of white dashes followed by wider white and black bars which periodically flash in odd patterns.
To us this looks like a visual effect, but to the right decoder chip this is a signal repeatedly going between high and low in set patterns -
and thus, it’s a binary data stream.
Multiple things could be done with this data stream but here in the US it was mainly used to transmit EIA-608 caption data.
That’s a mouthful so from now on I’ll be calling it line 21 captions.
And it was up to the TV (or a decoder box like this) to decode this bitstream and display the encoded text on the television screen when requested.
This technology was basic and quite low-bandwidth, but it was extremely robust and worked properly with poor television reception
and with home video formats like VHS.
In fact, here’s a TV from 1994 playing a tape recorded from over-the-air TV in the lowest quality SLP mode and still the captions work perfectly.
So, where does DVD fit into this?
Well, it entered a landscape where line 21 caption decoders had existed for over a decade and were now mandated by law.
And prior home video formats like VHS, Betamax, Laserdisc, and even RCA’s ill-fated CED had supported closed captioning.
Since the folks who relied on captioning were used to a system where the captions were simply built into the video signal
and either their TV or their caption decoder would just… work whenever captioning was available,
the DVD standard required DVD players sold in markets which use the NTSC television standard
to transmit line 21 caption data in their video output whenever they are playing a disc.
The text, timing, and positioning data for the captions is stored on the disc in the group-of-pictures headers found in the MPEG-2 video stream,
and as part of the digital-to-analog conversion process, a DVD player will extract that data and spit it out over line 21.
Then, without doing anything extra, any TV with a caption decoder could display the captions on the disc
in exactly the same fashion as every other video source it might encounter.
Now, I had always assumed that the main reason this was done was for backward compatibility and ease of access.
See, the DVD format also included a completely new version of closed captioning which it called subtitles.
Side-note: if you insist on being pedantic, subtitles and captions have different definitions and purposes.
Sticklers will insist that captions need to include both dialogue and anything audible, like the noise of a telephone ringing,
while subtitles should only display spoken dialogue or translations into other languages.
But when it comes to the technology and what it does, line 21 captions and DVD subtitles are doing the same thing.
They’re both a form of text information which is hidden until the user selects it.
That’s, by the way, why closed captions are called closed.
The DVD format just calls its version of that concept subtitles, which happens to be a convenient distinction.
However, there are significant technical differences between the two.
For one, DVD-video allows for up to 32 subtitle tracks, which is why we had all those different language options at the beginning.
Line 21 captions technically have four concurrent data streams and support multiple languages,
but the bandwidth limitation meant in practice there were at most two options.
So DVD subtitles could handle much, much more information.
And DVD subtitles aren’t just more plentiful, they’re also not stored on the disc as text.
In fact these are bitmap images that the DVD player will display on top of the video.
This allowed for the use of any colors, fonts, and languages you can imagine so it had lots of advantages over the standard text blocks of closed captions
and could be used in many different ways.
Despite those advantages, DVD subtitles required learning a new system which not everyone would want to do.
In fact, if I remember right, my family’s first DVD player didn’t have a dedicated button on its remote control for turning on subtitles
and you had to navigate through the clunky DVD menus to enable them.
Designers were having a little too much fun with those in the early days of DVD.
So if you regularly used captions,
DVD subtitles could be much more annoying than having your TV just… do it whenever it’s getting a video signal as it always had before.
I suspect that’s the main reason the DVD standard wanted to support line 21 captions.
It was simple enough to implement them so there really wasn’t a good reason not to,
and, when closed captions are part of the output signal, it would make accessible television broadcasts from a DVD source much more technically straightforward.
Just shove it into the transmitter.
But I didn’t realize until I bought my Perry Mason box set that there were DVDs out there which ONLY support line 21 closed captions.
I’ve gone on to find plenty of other examples among my DVDs -
it seems a lot of DVD releases of TV shows simply put the same closed caption data from the television broadcast on the discs
and they never got converted to a subtitle track.
In 2025, this presents an interesting accessibility problem.
See, the DVD standard quite correctly envisioned that line 21 captions would simply always be happening in the background.
There’s no way to turn them on or off because that is handled by the television.
But as time has marched on, people aren’t using analog video connections so much.
And as this Blu-ray disc player shows us, that has led to some oversights.
See, HDMI doesn’t carry caption data.
Notice how the Accessibility and Captions option in this TV’s menu changes to simply “Accessibility” when I switch from the composite input to the HDMI input -
and yes, I checked, there are no caption options in that submenu.
This means if I play my Perry Mason DVDs on this Blu-ray player and I have it hooked up to my TV via HDMI, the captions simply don’t work.
Which is kinda bonkers if you think about it because this Blu-ray player sees the caption data!
It has to get it from the DVD in order to inject it into line 21 of its composite video output -
which it is doing!
So it’s not only aware that there are captions on this disc it's playing,
it’s actively decoding them.
But during the design phase nobody thought
“well we’d better figure out a way for the Blu-ray player to render those captions on-screen for those using HDMI or component video”
which means the captions on many discs appear to be broken.
They’re not - as we know, because… there they are.
But should anyone want to enjoy the benefits of upscaling and watch their DVDs through the same cable that they watch their Blu-ray discs,
well they’re not getting captions from this thing.
Quick tangent - if you’ve not seen a well-mastered DVD being played on a Blu-ray player (or an upscaling DVD player)
then you’ve not seen how good DVDs can look.
Yes, the resolution of the video is only 720X480 which means, technically, the DVD only stores the same number of pixels as YouTube set to 480P.
But in practice the image quality is miles better than that.
I have a lot of movies on DVD that I will happily watch on my 4K OLED TV because they still look pretty good.
Obviously not as good as Blu-ray or most streaming video services, but it’s way better than a format from 1996 has any right to be.
Heck, even the film grain comes through on these Perry Mason DVDs.
There’s a reason new DVD releases are still happening - it’s a fine format,
and honestly I’m really enjoying getting back into the experience of "here’s a thing, it has the movie on it, and I put the thing in the player and watch it -
no internet required!"
Plus, I have the thing!
Seasons 6-9 aren’t going to disappear like they did from Paramount +.
But back to the captions.
The inability of this Blu-ray player to display them sent me down a bit of a rabbit hole.
It’s understandable that a Blu-ray disc player from 2009 which still has a composite video output would not have a way to render line 21 captions on its own.
Worst case scenario you do what I did here and hook it up to your TV twice:
use the HDMI (or component) output for Blu-rays and DVDs with subtitles
and then switch over to the composite input on your TV whenever you run across a DVD which only has closed captions.
It’s not an ideal experience, and it’s also something you’re just gonna have to figure out on your own
since this whole compatibility problem isn’t mentioned anywhere in this thing's user manual,
but at least it makes some flavor of sense.
HDMI is a new cable which doesn’t work like the old one.
Get used to it.
But, uh, a check of the calendar reveals 2009 was 16 years ago
and there are plenty of Blu-ray players out there which don’t have any analog connections because time has passed.
Like, for instance, this 3D Blu-ray player.
It’s like a Blu-ray player, but twice!
It’s only got an HDMI output so line 21 captions are definitely not going to work.
However, it’s got that DVD-video logo on there (you can barely see it but it’s there) and it will play DVDs.
Did Sony think of what would happen when someone wants to watch a DVD like this and turn on captions?
No they did not.
The subtitle button doesn’t do anything, and the options menu reveals nothing helpful.
Great job!
Now, granted, this is a Blu-ray player.
It’s not selling itself as a DVD player, that’s just a feature it offers for convenience.
But, you can still purchase new DVD players in a store.
And so, for science, I did.
And I bought two of them.
One of them is Walmart’s ONN brand and was priced at $35, which is about what I would expect.
And the other is a Sony which was $55.
That’s too much to spend on a DVD player but I did it anyway because in 2025, there are lots of TVs out there which don’t have composite inputs.
Including mine.
And both of these DVD players have HDMI outputs because that is how we do video now.
So, did anyone during the design process of these machines remember about those closed captions on DVDs?
Only one way to find out!
Starting with the Walmart one,
this thing’s power cord ends in a USB plug which is amazing.
Also amazing? It actually has a numerical display on the front to show status and runtime.
That is a very surprising thing to see on one of these cheap little DVD players, but it’s welcome.
I don’t necessarily need it to say OFF whenever it’s off but I’ll take it.
So - does this have a way to display closed captions?
No.
Pressing the subtitle button simply causes it to say “invalid entry” and there’s nothing in its settings - or its documentation
- to suggest it will ever display those captions on the screen.
But it does have a composite output and — of course — it’s sending the caption data out of there exactly as it should.
However, if I were to use a composite-to-HDMI adapter, captions would not come through.
So, unless your TV happens to have a composite input you're not using, you’re completely out of luck.
But in fairness, if we pretend it’s the year 2002 this is a perfectly cromulent DVD player which has this weird extra port for some reason.
Actually, quick note about composite to HDMI adapters.
These things are cheap, widely available and they generally work shockingly well.
Converting analog video to a digital grid of pixels is hard enough, and converting interlaced video is even harder,
yet the video these things put out of their HDMI port is generally great.
It’s remarkable that we’ve got that down to a commodity chipset, and you can pick these up for less than $20.
But as far as I can tell, none of them will decode and render line 21 captions.
This feels like a miss, and I hope somebody out there will build that feature into one of these with a toggle to turn captions on and off.
I really don’t like that we’ve just abandoned the deaf and hard of hearing community here.
It’s old tech, yes, but it works and there’s no reason we shouldn’t expect it to keep working.
But now let’s see if the Sony one does any better.
I have higher hopes for this guy because of something I’ll show you in a bit but…
no.
Same exact story.
Subtitle button doesn’t do anything, there’s nothing in the options mentioning closed captions, and the documentation is completely mum about this.
But it has a composite output and the caption data is correctly being sent out on line 21.
So both of these DVD players will correctly do closed captions so long as you’re in 1996
but neither one thought to update that functionality for 2025.
Great work, folks!
But then a thought occurred to me:
is this actually a new problem?
And it turns out - not really!
This is a portable DVD player from 2005.
These were everywhere for a hot minute and, since they have their own built-in displays,
you would think it should be able to display the captions on these discs.
But can it?
Nope!
On discs with subtitles it can display them, of course (though they aren’t super readable thanks to its pretty low-resolution display)
but it has no ability to display closed captions.
Which is extra frustrating because it’s got a composite video output on the back and if you hook this up to a TV -
well the TV will decode them just fine.
So somewhere in the logic of this thing it’s extracting the caption data and correctly injecting it into its composite output,
but if you want to see them on the device itself you’re out of luck.
Seems like a pretty big oversight to me!
But, OK, these things are really just cheap DVD players with a monitor strapped onto them
and DVD players were never designed to display the closed captions - they just had to inject them into the video output for a TV which,
since this can do, means that arguably there’s nothing wrong with it but it's still a pretty big accessibility failure, don’t you think?
But in 2005 we also watched DVDs on our computers, at least those of us with a DVD-ROM drive.
Do they know what to do with the closed captions?
Well, it turns out that answer is pretty complicated.
In the past, this worked great.
I fired up this Windows XP machine and good ol’ Windows Media Player.
And sure enough, there’s a setting in the options menu to turn on closed captions and they work exactly as you’d expect.
I then fired up a Windows 10 machine which had been upgraded from Windows 7
(in case you forgot, Microsoft stopped licensing DVD playback with Windows 10
but if you upgraded from 7 they’d transfer the license built into that and let you use this Windows DVD player app. How fun!)
and it… also works just fine.
In fact it’s got a nice and obvious CC button to turn them on.
Genuinely, great job!
But for those who weren’t blessed with that specific provenance of Windows upgrades,
playing DVDs on a computer in 2025 requires a traffic cone.
And an optical drive… anyway while VLC can see the caption data
(and in fact it lets you select between the four data streams in the EIA-608 standard)
it’s… really quite awful at rendering them.
It’s kind of astonishing, really, the right side keeps going off the edge of the player and this also happens in full-screen mode.
I’ve also noticed some pretty bad decoding errors in some of the captions
which aren’t present on a real TV decoding them the old-school way -
so it’s not an error on the disc.
I hadn’t updated VLC in probably ever so I did to see if this might have been fixed and, uh, the answer appears to be no.
The captions changed a little bit but they’re still routinely falling off the right edge of the screen and those errors are still there.
This surprised me.
VLC’s kinda crappy work, along with the 3D Blu-ray player and the two DVD players which were manufactured less than 12 months ago
seem to suggest that people simply forgot about those line 21 captions.
So I did a little digging into this.
I merely tolerate computers and aren’t into some of the stuff y’all are like homelabs and plex servers and stuff,
but I figured this might have become a problem for those who like to back up their DVDs and also use captions.
The answer I’ve found is
[shrugs]
Not a lot of people who are into hoarding media like that seem all that concerned about captions,
and for those who are - what I read suggests that the way DVD handled line 21 captions in the MPEG2 container is more than a bit odd
and requires conversion when moving to a more modern video format which doesn’t always work that well.
But a lot of what I’ve run across doesn’t make a clear distinction between DVD subtitles and line-21 closed captions
(which makes sense because it’s a confusing distinction) but it makes research into this rather difficult.
In a modern context, image-based DVD subtitles are actually much weirder and so they’re harder to get working -
and I can’t easily differentiate between what people are talking about as they discuss this stuff on Reddit and junk.
So I don’t really know what’s up and I gave up trying to find out.
The main thing that I’m concerned about, here, is that DVD backups actually contain the caption data.
Disc rot is a known problem so we can’t guarantee that any particular DVD is going to be readable in the future.
If the entire disc ISO is backed up and a bit-perfect copy can be reproduced then that data will be there,
but I really don't know whether the captions are being correctly handled in the various ways people may convert DVD video from MPEG2 into something a little more modern.
But I bet the comments will know!
Now, in some respects, I get it.
DVD subtitles are their own thing, and closed captioning was never really a “function” of a DVD player.
It was just something that happened automatically in the digital to analog conversion process.
But it’s really quite odd to me that so many devices have been sold which cannot process and render those captions for modern displays.
But I do have some good news.
Not everyone forgot.
I have one more Blu-ray player at my disposal, and it’s this 4K Ultra-HD Blu-ray player.
Unlike the 3D Blu-ray player, when you go into the options menu on this one there’s a selection for closed captions.
And holy crap, it works!
Mostly!
It’s rendering them on the bottom left of the screen for some reason which wrecks the positioning that was lovingly encoded into this caption stream,
but at least they're visible!
And you can even change the font and the color if you like.
My hat goes off to whichever engineer at Sony remembered about those captions and made sure this Blu-ray player could display them over HDMI.
There’s a little room for improvement, and it supports software updates so maybe the current version is better,
but I am not connecting this thing to the internet to find out.
For all I know an update will break it.
However, the Playstation 3 provides some more evidence which suggests this is a function that people just keep forgetting about.
Because it renders line 21 captions perfectly.
You have to go into the settings to enable them
(honestly I have no idea why nobody thought
“if there are no subtitles on a disc, make the subtitle option turn on line 21 captions” because it seems to me like that’s a pretty obvious fallback strategy
and much more user friendly than making it an option you’re going to have to turn on and off outside of the player interface)
but at least it works.
I haven’t used this thing in years so whatever version of the software it’s running is definitely older than the software on the 4k Blu-ray player,
and that’s why I think the institutional awareness of this DVD feature is slowly fading away.
Although, if you change the font option on the PS3,
then it does the same weird rendering on the bottom left that the 4K Blu-ray player does. So it’s still got some bugs.
Now I don’t have a PS4 or PS5 to test how they render captions,
but the Sony website suggests they both have a closed captioning option so I would expect both of them to at least work as well as the PS3 does.
And it looks like Microsoft has implemented this correctly on Xboxes with optical drives, as well.
Since those game consoles probably outsell every Blu-ray and DVD player model at this point, well, at least it’s not completely dead.
But I still find it incredibly baffling that these new DVD players which have one job — play DVDs — can’t do it.
Unless you use composite, of course.
Oh and, FYI, the PS3 is spitting out line 21 data through its AV multi-out port when it plays DVDs.
So hook it up that way to your old Trinitron and you’re good to go.
But that’s all for now.
I think accessibility features are very important
and it’s great that we have so many technologies now which help those with disabilities to experience media and even the broader world.
But we can’t just abandon the old ones.
Sure, not all captions are done that well but many of them were done with much more care than any automatic captioning system could ever achieve.
And while I don’t personally use captions all that often, I think they’re important.
DVD hasn’t run off into the sunset just yet, which makes this incompatibility problem extremely annoying -
but one day it will be truly obsolete, and I hope that media preservation folks are thinking about how to get those captions (and subtitles!) working in DVD backups.
But I suppose the good news is that the 8.5 gigabytes a dual-layer DVD can store is no longer very huge.
You could backup 1,000 DVDs on a $150 hard drive.
I should probably do that.
Uh, so if nothing else - a little reverse engineering from saved ISOs should do the trick.
For now, though - I like putting the thing in the thing.
Media collections are a lot more fun when you get to interact with them.
♫ selectably smooth jazz ♫
Before the bloopers, quick announcement:
I’ll be at Open Sauce again this year which is happening between July 18 and the 20th in the San Francisco Bay Area.
This is a really cool event that I’ve really enjoyed going to, and if you’d like more information about it there will be a link in the doobly-doo.
So this Blu-ray player sports analog video outputs, too.
Including ba - ah I didn’t hook it up!
I forgot about that part.
And either their TV or their caption decod -
decoder. Gotta caption decoooder.
Up in North Dakoooder.
Because they still look pretty darn good.
Stupid loud cars!
Uh…. hello? Where’s the…
where’s the bright blue box?
Though they aren’t super readable thanks to its pretty rolululululu augh!
Its pretty row lesorution - I can’t even say that.
Row lesol - lesolution?
Reso, le - lesolution. That’s hard to say.
Notice how the accessibility and captions options in the…
well farts.
CBS Presents: Perry Mason starring Raymond Burr in
Erle Stanley Gardner's The Case of the Forgotten Captions
That's for those Perry Mason fans out there.
I know there are at least a dozen.
Seriously if you're looking for some good old fashioned drama with a side-dish of a hopeful representation of how the justice system is supposed to work... it's refreshing.
If very, very dated.