SDH subtitles are subtitles for the deaf and hard of hearing. An SDH track writes down the dialogue in the same language as the audio, plus everything else the sound tells you: who's speaking when you can't see them, sounds like [door slams], and music. It does the same job as closed captions (CC), but it's made and shown as a subtitle track, which is why you'll find SDH on streaming services, Blu-rays and DVDs. If you see "English (SDH)" in a subtitle menu, that's the track to choose if you can't hear the audio well.
![A video player with the subtitle menu open and 'English (SDH)' selected. The subtitle on screen reads '[wind howling]' on the first line and '[man] Is anyone out there?' on the second](/images/blog/sdh-subtitles/sdh-track.webp)
What does SDH mean?
SDH stands for subtitles for the deaf and hard of hearing. In a subtitle menu it always means this, even though the letters mean other things elsewhere.
The name says what the track is for. Ordinary subtitles are written for viewers who can hear the audio but need the words, usually because the film is in another language. They leave out sounds, because the viewer can hear them. SDH is written for viewers who can't rely on the audio, so it puts the sounds back in.
Netflix's partner help center sums it up: SDH looks and works like subtitles, but it's for the same viewers as closed captions and holds the same information.
What's in an SDH track?
An SDH track has the dialogue, plus four kinds of extra information. The examples below follow Netflix's English style guide, which many subtitle makers follow:
- Who's speaking, when you can't tell from the picture: [man], [woman], [narrator], or a name, such as [Maya]. If you can see who's talking, there's no label.
- Sounds that matter to the story, in square brackets and lowercase: [door slams], [phone buzzing], [dog barking in distance]. Sounds you can work out from the picture are left out.
- Music and lyrics. Background music is described, such as [tense music]. Song lyrics are written out word for word, with a music note at each end: ♪ Take me home ♪.
- How things are said, and in what language: [whispering], [sighs], [in Spanish] for a line that's then translated, or [speaking Spanish] for one that isn't.
Everything else works like ordinary subtitles: the text sits near the bottom of the screen, in one or two lines, timed to match the speech.
SDH vs closed captions (CC)
For a viewer, SDH and closed captions give you the same information: dialogue, speakers and sounds. The differences are in how they're made and how they look.
| SDH | Closed captions (CC) |
|---|---|
| A subtitle track, like the one for any other language. | Caption data sent with a TV broadcast and drawn by the TV or player. |
| Looks like subtitles: white or yellow text with a shadow or outline, near the bottom. | Often white letters on a black box, and can move around the screen to show who's talking. |
| Up to 42 characters a line in Netflix's English style guide. | Up to 32 characters a row in the standard US TV format. |
| Used by streaming services, Blu-rays and DVDs. | Used by US TV, and online for shows that aired on TV. |
| Can use the same fonts and colors as the other subtitle tracks. | Style depends on the TV or player's caption settings. |
The reason SDH exists is technical. US TV captions are a separate signal that the TV decodes, and that signal isn't carried over HDMI, the cable between a Blu-ray player and a TV. So Blu-rays carry captions as an SDH subtitle track instead, and streaming services deliver them as subtitle tracks too.
In everyday use, people mix the two words up, and many menus label the SDH track "CC". Netflix says itself that SDH and CC are often used to mean the same thing. If you can't hear the audio, either label gets you what you need.
SDH vs regular subtitles
This is the difference that matters most when you pick a track:
- Regular subtitles show the dialogue only. They're often a translation into your language, and they're written for viewers who can hear.
- SDH shows the dialogue plus speakers, sounds and music, in the same language as the audio.
So "English" and "English (SDH)" on an English-language film aren't the same. Watch a horror film with plain "English" and you won't know about the footsteps behind the door; with SDH you will. Our guide to closed captions vs subtitles covers the wider difference between captions and subtitles, including forced subtitles.
Some hearing viewers choose SDH anyway, because it catches quiet lines and background sounds. Others find the sound tags distracting and prefer plain subtitles. Either is fine.
How to turn on SDH subtitles
On Netflix: look for the SDH badge on a title's details page to check it has SDH. Start playing, open the controls (tap or click the screen, or press up or down on a TV remote), choose Audio & Subtitles, and pick the track marked CC or SDH. Netflix notes that not every season or episode has SDH, and that without it you may get subtitles with dialogue only.
On other streaming services: open the subtitle menu while the video plays and look for a track marked SDH or CC next to the language, such as "English (CC)". A track with just the language name is usually dialogue only.
On a Blu-ray or DVD: open the disc's Subtitles or Languages menu, or press the subtitle button on the remote, and choose "English SDH". Turn off your TV's own closed captions if both show at once.
How to write SDH subtitles
If you make videos, SDH is the version of your subtitles that works for everyone. Start from accurate subtitles of the speech, then add:
- Speaker labels where a viewer couldn't tell who's talking: a voice off screen, a narrator, someone on the phone.
- Sounds that change what the viewer understands: a knock at the door, a notification, laughter, a sudden silence ([music stops]). Skip sounds that add nothing.
- Music, described in a few words, and lyrics written out between music notes if they matter.
- How a line is said, when the words alone would mislead: [sarcastically], [whispering].
Keep each subtitle to two lines, and keep lines short enough to read in time: Netflix's guide allows 42 characters a line and up to 20 characters a second for adult programs.
Here's what SDH looks like in an SRT file, the most common subtitle format:
1
00:00:01,000 --> 00:00:03,200
[wind howling]
2
00:00:03,400 --> 00:00:05,800
[man] Is anyone out there?
3
00:00:06,500 --> 00:00:08,900
-[branch snaps]
-[woman] Over here!
4
00:00:09,200 --> 00:00:12,000
♪ Soft piano music ♪
The same file without the bracketed lines and labels would be ordinary subtitles. Many people name SDH files with the language and "sdh", such as video.en.sdh.srt, so they don't get mixed up with the dialogue-only file.
For accessibility, SDH is the kind of subtitles that counts. The Web Content Accessibility Guidelines (WCAG), which most US and UK accessibility rules point to, define captions as including the sounds needed to understand the video, not only the dialogue.
How to make SDH subtitles for your video
With AutoSubtitles, in your browser, with no account:
- Open autosubtitles.com, click New Video and choose your video. Your video stays on your device; only the audio is sent for transcription.
- Check the words. The subtitles appear a few seconds later, line by line. Click any line to fix a word or its timing.
- Add the SDH parts. Type speaker labels and sounds into the lines where they happen, such as "[man] Is anyone out there?" or "[laughs]".
- Burn them in or download a file. Pick one of 28 caption styles and export the video with the subtitles burned in, free for videos up to 10 minutes (720p, small watermark). On Pro ($9/month) you can also download an SRT or VTT file to upload to YouTube or a video player.
Burned-in subtitles are called open captions: everyone sees them, and they're the only kind that shows on TikTok and Instagram, where many people watch with the sound off. Our guide on how to add subtitles to a video has the steps for YouTube, TikTok and Reels.
Already have a subtitle file? Open it in our free subtitle editor. It runs in your browser, so you can add lines for sounds and speakers between the dialogue and save the file again as SRT or VTT. If the lines are all early or late, the subtitle shifter moves them in one go.
Frequently asked questions
What does SDH mean on subtitles?
SDH stands for subtitles for the deaf and hard of hearing. An SDH track includes the dialogue plus speaker names, sound effects and music, in the same language as the audio, so viewers who can't hear the audio don't miss anything.
Is SDH the same as CC?
They hold the same information: dialogue, speakers and sounds. The difference is technical. Closed captions are TV caption data drawn by the TV, often as white text on a black box. SDH is a subtitle track, shown like ordinary subtitles. Many menus use the two labels for the same thing.
What is the difference between English and English SDH?
"English" is usually the dialogue only. "English SDH" adds who's speaking, sound effects like [door slams] and music. If you're Deaf or hard of hearing, choose SDH. If you can hear and just want the words, plain English is less cluttered.
Should I choose SDH or CC?
If both are offered, choose the one whose look you prefer; they carry the same information. On a Blu-ray played through HDMI, choose SDH, because TV closed captions don't always come through.
Why do my subtitles describe sounds?
You've probably turned on the SDH or CC track. Those describe sounds and music for viewers who can't hear them. To get dialogue only, pick the track with just the language name.
Are SDH subtitles only for deaf viewers?
No. They're written for viewers who are Deaf or hard of hearing, but anyone can use them, for example when watching with the sound low, in a noisy place, or when a show's dialogue is hard to follow.
Do SDH subtitles meet accessibility requirements?
They can. WCAG defines captions as covering the dialogue and the sounds needed to understand the video. Accurate, well-timed SDH does that; dialogue-only subtitles don't.
How do I make SDH subtitles for free?
Generate subtitles for your video with a free tool such as AutoSubtitles, then add speaker labels and sounds in square brackets where they happen. You can burn them into the video for free, or edit an existing SRT file in a free subtitle editor.