Described Video for TV in Canada

Producers who are creating spots that will have Described Video added should be aware of what this service is, who it is for, and how to best prepare and deliver elements to be used by the Extreme Reach team.

What is Described Video?

Described Video (DV) is audio-narrated descriptions of key visual elements. These descriptions are inserted into natural pauses in the dialogue. Described Video makes television more accessible to individuals who are blind or visually impaired.

Does Described Video change how I create an Ad?

Described Video is often added well after the production phase is complete, but this often presents a problem. Many ads feature “wall-to-wall” audio, which doesn’t leave any time for a Video Describer to speak descriptions of the video. In some cases there is no possible way to add any descriptions. However, if a producer is aware that Described Video is required, there is an option. Because the DV track is a completely self contained track, an alternate mix can be created that does leave space for the DV to be inserted. Creating this alternate base mix will NOT affect the regular Stereo or Surround mixes created for the spot. Only people who have chosen to enable the SAP Audio channel in their set-top box or television will hear the alternate mix.

What elements should I supply to Extreme Reach?

If the mix contains enough free space to insert Described Video lines, only the final stereo and surround (if available) mixes are required. If you are going to produce an alternate mix that allows for more space to insert Described Video lines, that mix should be supplied as a stereo audio file clearly labeled as “Ad-ID_DV_BaseMix (e.g. ABCD1234000H_AD_BaseMix.wav)”.

If you are supplying a finished DV track along with the finished spot and regular audio, the DV track must be on channels 11&12 of a 12-channel file (typically Pro Res or equivalent QuickTime).

The Described Video track is broadcast on the Secondary Audio Program (SAP) channel that all broadcasters air alongside the regular audio channel. In a typical cable/satellite provider scenario, a television viewer can change a setting in the set-top box to switch the audio feed to the SAP channel. This stream could be labeled as “SAP”, “Described Video”, “Alternate Language” or “Video Description” all these selections will provide the programming assigned to this alternate audio channel.


Any questions?

Contact us at or 800.324.5672 for a more personal discussion regarding your workflow and needs.


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