CAPTION ENCODING

Before we dive in, let’s review how caption encoding technology works. Most encoders function similarly:

1: The caption provider transmits their caption data to the encoder.

2: The encoder collects the caption feed for transmission to the viewer.

3: The encoder pairs the captions to the video on a specific data transmission line, known as line 21– this is the data that televisions are mandated to decode captions from.

With 3Play Media, you’ll upload your video file for captioning and transcription processing. If you already have a transcript, you can use the automated transcript alignment service. Once your file has been captioned, you can order the caption encoding service and choose the appropriate encoding profile. Upon completion, you will receive an email notification and be able to download an M4V video with encoded captions.

The video will work with any player or device that supports M4V videos, including QuickTime, iPad, iPhone, iPod, iTunes, JW Player, and Flowplayer. Because the captions are soft-encoded in the video, users will be able to turn them on or off using the video player controls.

Telco Encoders

While based on older analog technology, many still stand by dial-up telco encoders. A telco encoder requires phone lines to connect to. For optimal setup, a service provider will need the phone number to dial in order to connect with the encoder’s modem. To get an audio feed and follow along with what is being spoken, the caption writer will need a designated audio source to listen to. Broadcasters can route the audio through an audio coupler for the captioner to dial with their phone, or they can provide an internet-based solution such as a web conferencing platform or low-latency stream for the audio.

Telnet Encoders

A telnet encoder uses an IP and port number to receive the caption data. Like with a telco encoder, a service provider will also need a separate audio line to hear the dialogue. While connections are now almost instantaneous, this does require extra checks and tests as different network security protocols can block incoming or outgoing caption data. A bonus to this type of encoder is that phone lines don’t need to be run into the encoder; an internet connection (ethernet) is typically required.

iCap Encoders

An iCap-enabled encoder is manufactured by EEG, and with their direction, you can set up the encoder to feed both audio and video to our captioner, making it easier to monitor and caption effectively. These EEG-manufactured encoders have iCap software for improved functionality, such as sending audio to the captioner, but can also be set up as IP connections if desired. The video and audio are converted to a data stream on the iCap cloud which is accessible via an Access Code. Captions are routed through the cloud and into the encoder where it is married to the stream and ready for broadcast. These encoders can be bought or rented for any type of event or broadcast.

The source video that you upload can be in almost any web format that doesn’t use a proprietary codec. When ordering caption encoding, you will have the option to select an encoding profile to optimize video playback for a certain device.

For example, the iPhone5 profile transcodes your video for a target width of 1136 pixels, 30 frames per second, and a frame rate of 3 Mb/sec. You can also use your original source video as long as the video encoding is H.264 and audio is AAC. The closed captions track will be added to the video and put in an M4V container.

Download a demo video with encoded closed captions – you’ll need to play it in a QuickTime or VLC player and make sure to enable the captions (subtitles). Please note that some versions of Windows Media Player do not support caption-encoded videos.

Note: For social media videos, you’ll need to upload your video in a format supported by the social platform (for example, Twitter takes MP4 videos). Then, order caption encoding > source with open captions.