Embedded Closed Captions CEA 708 captions for Commercial Ads.

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Embedded Closed Captions- CEA 708 Captions for Commercial Ads.

Embedded Closed Captions- CEA 708 Captions for Commercial Ads.


An award-winning marketing and advertising agency, has created history by pooling in many customers to its clients through its innovative advertising models on any platform. They can offer search ads, product listing ads, YouTube advertising, Gmail ads, and more. The company offers various solutions to video production, search engine optimization, social media management, brand strategy, media planning, and website design, a complete end-to-end package for clients.


Nate Liebold, is a producer who produces commercial ads for her clients. A few of them requested to add captions to their commercials. Nate generally includes embedded captions in-house using Adobe Premier and Apple Compressor and exports them as burned-in, but this time, these captions need to be embedded within the MPEG-2 file (not burned-in) as closed captions where the viewer will be able to toggle captions. 

It was then she interacted with CaptioningStar to receive embedded closed captions with ON and OFF options for her TV ad broadcast. If the former MPEG-2 format did not support embedded closed captions, we were also asked to try in the MXF video format.

TV Station Requirements

We also had to accommodate several other TV station specifications upon adding captions. These specs were to be strictly adhered to prevent any disruption in the video stream.

Station Requirements : 


  1. Container Format: MPEG-PS (program stream)
  2. File Extension: .mpg

Video Specs:

  1. Compression Codec: MPEG-2
  2. Screen Size: 1920×1080 (1080i)
  3. Display Aspect Ratio: 16:9
  4. Pixel Aspect Ratio: 1.0 (square pixels)
  5. Scan Type: Interlaced, Top (Upper) Field First
  6. Frame Rate: 29.97 fps (constant/fixed)
  7. Frame Rate Mode: Drop Frame (DF)
  8. Bit Rate: 35 Mb/s CBR (constant bit rate)


  1. Audio – MPEG-1, Layer II Audio, Stereo, 320 Kbps Bitrate, 48000 Hz Sample Rate, 16 Bit

The requirements mentioned above are the export specs for all embedded Closed Caption files.

Caption Samples

Understanding all the requirements and TAT, without any further delay, our executives sent the dropbox link through which the MPEG-2 files should be uploaded. Nate uploaded thirteen ads, and we downloaded them. Since she asked us for true closed captions that should be encoded using the MPEG-2 codec, we confirmed CEA-708 embedded closed captioning data as they are the new standard for closed captioning for digital television streaming in the United States. The captioning shall then be inserted in the VANC space on line 9, luminance channel, in accordance with SMPTE 334M. 

We decided to process a 5-second video file as a sample to ensure to get the desired video output and the closed captioning format. We tried different captioning formats to guarantee them maintain the TV station specs. Thus we sent them three different formats for their perusal to know which worked the best for Nate. 

Against all the odds, remedies from CaptioningStar

Upon review, she understood that the sample MPEG-2 file seemed to have a lower bitrate, around 9 Mbps instead of the required 35 Mbps. Nate was very particular with these videos as they all needed to be exported with the above-mentioned specifications, despite making them larger files via Adobe premiere. 

We then started working on the bitrate revision. Later we understood that MPEG 2 was the old version, and producing embedded closed captions with an on/off option and other required video specifications was unattainable with Adobe Premiere. After thorough research, the in-house production team learned that these captions were possible with the updated version,  MPEG-4 compression Codec, using Mac captioning. With the updated version, we achieved the desired bitrate and were able to satisfy the other specifications with toggle captions.  

After putting in a lot of effort, embedded closed captions- CEA 708 were added to all the ads, and they were uploaded to the dropbox link for the customer to download. Nate was extremely satisfied with the caption files, and we are currently working on their other projects as well.

Broadcast Captions for various other services

We work with all over-the-air television networks. Broadcast networks can be commercial, non-commercial, shopping, educational, and many more. We interact with the hundreds of millions of users who watch these networks worldwide by providing flawless closed captions and live captions. Captions are a huge benefit for people who are hard of hearing, deaf, or non-native English speakers. Simply hiring us is all that is required now.

Not only TV stations, but we also work for advertising agencies, web broadcasters, record companies, music promoters, broadcast cable networks, and award shows, ensuring the highest quality captions. We are a part of other events, conferences, remote meetings, news and weather reports, sports, concerts, etc.

In addition to TV stations, we provide enhanced accessibility services to live broadcasts and various VOD and OTT platforms. We accommodate most of the broadcast captioning formats used by television networks and streaming providers.