UPDATED: October 26, 2020

Overview

Enabling Closed Caption support on the encoder

Troubleshooting

Example of of typical Closed Caption workflow

Overview

Closed Caption (CC) support is present on the following encoders with SDI video input:

• 1st and 2nd generation Cube encoder*
• Bond II, Bond Pro*
• 1st generation Slice encoder*
• 1st generation T-RAX encoder card*
• 600 series : Cube 605 and Cube 655 encoder; Slice 656 encoder; Bond 657 and Bond Backpack 659
• 700 series : Cube 705/755, Slice 756 encoder, Bond 757 and Bond Backpack 759, and the 2nd generation T-RAX HEVC series have Closed Caption support as of firmware version 8.2.3.
• VidiU Go : SDI model as of firmware version 3.1.6; Closed Caption support is not possible on the HDMI-only version of the VidiU Go, or any prior VidiU models such as the VidiU Pro or the original VidiU.

* NOTE: when these older generation encoders are streaming through a Core account or a standalone Sputnik server, Closed Captions will not be present if running firmware versions 7.3.9 through 7.3.14. Streaming direct from the encoder to the destination will preserve captions, it is only if the stream is passing through a Sputnik server that those firmware versions are affected. For that latter workflow please use firmware versions before 7.3.9 or after 7.3.15 for Closed Captions to be present on the stream. 

Streaming protocol support:

• when sending direct from a Teradek encoder to the destination, only the MPEG Transport Stream (MPEG-TS) and RTMP streaming protocols will have embedded Closed Caption data
• when sending from a Teradek encoder (e.g. Cube Encoder, Cube Encoder combined with an original Bond, Bond II, Bond Pro, Slice Encoder, T-RAX Encoder or 600 / 700 series products) to a Sputnik server in Core, all streams sent out by the Sputnik server will have embedded Closed Caption data

Video input: SDI input only
CC type supported: EIA-608 and EIA-708
Insertion method: inserting into H.264 SEI, as per SCTE 128-1

NOTE:

1. all current Teradek Decoder products do not have support for outputting Closed Captions as either SDI metadata, or burned in to the displayed video, so you'd need to use either software products (such as VLC media player) or third party hardware decoder products which support the output of Closed Captions.

2. Regarding EIA-608 support:

• Closed Captions formatted to the original 608 standard were inserted into line 21 of an analog NTSC signal. With the introduction of DTV, some manufacturers may have inserted the same caption line into a digital SD-SDI signal. This type of caption is NOT supported on our SDI Encoder products.
• SMPTE 334 defined how to insert 608 captions as a digital ancillary VBI data packet. This VBI data packet is the type of Closed Caption extraction that is possible with our SDI Encoder products.
• EIA-608 Closed Captions are embedded as EIA-708 Closed Captions into the H.264 stream.

3. Our products do not convert / transcode from EIA-708 down to EIA-608 formats.

Enabling Closed Caption support on the encoder

Log in to the Web User Interface of the respective product and perform the following steps to enable Closed Caption support.

1st / 2nd generation Cube, Bond II and Bond Pro, 1st generation Slice:

1. Select Video Setup, then Device Settings. In the SDI Ancillary Data section, under H.264 SEI Insertion choose Closed Captioning, then click Apply.
2. Select Video Setup, then Encoder Settings. Click the Primary Encoder tab; in the Advanced Encoder options ensure that SEI Timing is set to Enabled, then click Apply. NOTE: If the Advanced Encoder Options are not shown, click the Show Advanced Settings button at the bottom right of the Web User Interface.

1st generation T-RAX

1. Select Cards, then Configuration. Click Edit next to the T-RAX encoder card which is receiving the CC video source.
2. Select Input. In the SDI Ancillary Data section, under H.264 SEI Insertion choose Closed Captioning, then click Apply.
3. Select Encoder. Click the Primary Encoder tab; in the Advanced Encoder options ensure that SEI Timing is set to Enabled, then click Apply. NOTE: If the Advanced Encoder Options are not shown, click the Show Advanced Settings button at the bottom right of the Web User Interface.

600 series

1. Select Video / Audio Input.
2. In the Video Input section select SDI Ancillary Data, then set Closed Captions to Enabled and click Apply.

700 series

1. Select Video / Audio Input.
2. In the Video Input section select SDI Ancillary Data, then set Closed Captions to Enabled and click Apply.

VidiU Go

1. Select Settings, then Video/Audio.
2. In the Video Settings section set Closed Captions to Enabled and click Apply.

Troubleshooting

1. Most online streaming platforms do not support receiving captions at higher than 30 frames per second. If the captions seem to have extra characters inserted or the words appear garbled, make sure that you are not streaming at more than 30 frames per second on the encoder.

2. If streaming over RTMP, do not select the OnCaptionInfo option in the encoder's configuration settings unless your streaming service is specifically looking for captions in this format.

Example of of typical Closed Caption workflow

Inserting close captions into a Live SDI stream requires 3 parts

• Captionist (or auto captioning software)
• A caption encoder (EEG, Link Electronics, Evertz etc)
• Teradek encoder with SDI input and support for Closed Caption encoding

1. The Captionist types information into their software which sends either an IP or Serial stream to a caption encoder.

2. The caption encoder embeds the caption data received from the captionist into an ancillary data portion of the SDI stream.

3. The SDI video input with captions is passed to the Teradek encoder and streamed out to the destination.

Tested OVP / CDN / Streaming Servers with Closed Caption stream

• Wowza and Wowza-backed streaming services / platforms
• YouTube Live
• Facebook Live
• Ustream
• Livestream
• Twitch