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How to Choose a Captioning Service

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Companies with roots in live and broadcast captioning, such as LNS Captioning, use only human transcriptionists. For clients needing a fast, same-day turnaround, the company offers “as live” transcriptions, where a trained captioner treats a video like a live broadcast and then adjusts the timing of the transcription to make sure it synchronizes correctly. If an event is also available for live viewing or listening, a transcriptionist may be able to tune in to the stream to further expedite turnaround.

Formats and Platforms

According to Miller, “With most web video, 9 times out of 10 when you add captions you’re adding a separate caption file that gets associated with the video file.” At its most basic, a client sends video files to the vendor, which sends back a caption file. However, a vendor can also take over most or all of the publishing workflow too.

To make this process work, Erler says it’s important to know as much as possible about your video files. “What do you have right now? What format is your content in?” The next questions are, “Where is it going? Where do you intend to publish to?”

“We want to understand what (your) publishing process is,” says Miller. It’s important for a vendor to know if you’re using an online video platform, CDN, or a site like YouTube, and which one it is. This will allow the company to pick the right integration strategy and workflow.

A third-party video platform isn’t required; vendors should be able to work with self-hosted videos too. “Even if it’s just a QuickTime file,” Miller notes, “there are ways to add a caption track to those videos.” Both 3Play and Automatic Sync offer their own APIs for custom integration with a client’s own systems.

However, there can be advantages to using a video platform. “A lot of platforms out there offer APIs that we can integrate with,” says Erler. “Platforms like Kaltura or Brightcove allow you to go into your platform and check off the jobs you want captioned.”

Miller says 3Play’s web-based system also offers integration with video platforms. “It enables the ability to send files back and forth (for captioning) with just a couple of clicks.”

Having a sense of the quantity and frequency of video to be captioned will help the vendor tailor services. Quite simply, “We can turn it around really fast if we know you’re coming,” Studenmund advises.

“Is this a one-off or an ongoing need?” Erler says. “If it’s the latter, we can automate the workflow and take away some overhead.”

Names, Jargon, and Acronyms

It’s also good to tell a captioning vendor if your videos cover specialized or technical topics. “You can get specially trained transcribers in some fields,” Erler notes. “The medical field generates a lot of specifically trained transcribers, and we have a lot of [them] on staff. But there’s no training course for transcribers in Physics.”

“It’s good to have lists of names, technical jargon, acronyms,” Studenmund says. “If we can repopulate a dictionary, accuracy goes way up.”

Miller says that 3Play “even enable(s) people to upload a PDF of vocabulary with their video files.”


Accurate and clear English captions make it much easier to obtain translations into other languages. Some captioning companies may have experienced translators in staff, while many others outsource that service, but then ensure the results can be integrated as captions or subtitles.

Clear Voices for Clear Captions

It should be obvious: To get accurate captions, audio quality matters. “Audio comes to us in all kinds of conditions,” Erler says. It pays off in speed and accuracy to pay attention to microphone placement and take steps to reduce ambient noise.

Of course, that will only improve the overall quality of your video too. “If our transcription experts can’t make it out, your listeners won’t either,” he observes.

Also, if your videos have music or sound effects added in post, Erler suggests making a “pre-mix soundtrack” containing just the primary voice tracks to be captioned.


In the end, Miller says, “The added cost (of captioning) is tiny, compared to the cost of production.” He says the big question asks, “How do you make it as easy as possible while maintaining quality?” You want to select a company that can meet you where you are and make your captioning workflow as simple as possible with the accuracy you need.

Thinking about the future, Erler observes, “Chances are you’re going to end up switching platforms or finding new needs. You want a vendor to be able to move with you.” His advice is, “Make sure your vendor has a wide support for output types, [because] there are dozens if not hundreds of (caption) file formats.”

Sidebar: The Terms of Captioning

Online vs. Offline: “Online” captions are produced live, in real time, by specially trained transcriptions. If you’ve ever watched the captions for a live newscast or basketball game on television, you’ve seen “online” captions in action. Speed is the priority, so they tend to be less accurate than “offline” captions.

“Offline” captions are created in post-production, where transcriptionists create and align them in an appropriate caption file for an on-demand video. With this approach accuracy is the priority, and it’s easier to achieve.

Closed, Open, and Burned In: “Closed” captions are well-known because they are common in broadcast television. They’re called “closed” because the viewer can choose to turn them on or off. This is true for online closed captions as well.

“Open” captions are always displayed by default. However, according to Carol Studenmund, president of LNS Captioning, “Open captions don’t work in all devices.” So if open captions are required she instead recommends using “burned in” subtitles, which are superimposed on the video in post-production.

Sidebar: For the Do-It-Yourselfer

While this article focuses on choosing a captioning vendor, there are resources for those who want to take the DIY route. The Described and Captioned Media Program (DCMP) is funded by the U.S. Department of Education in order to ensure equal access to education for students who are blind, visually impaired, deaf, hard of hearing, or deaf-blind. The DCMP has drafted clear and explicit guidelines and instructions for creating good transcripts and captions, all available at its website.

This article appears in the 2014 Streaming Media Sourcebook as "Choosing a Captioning Service."

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