The Evolution of SDH

Subtitles for the deaf and hard of hearing (SDH) are similar to closed captioning in that dialog appears on screen as text in a film or program’s original language. However, SDH also includes descriptions of important non-dialog audio and speaker identification.

The major differences between closed captioning and SDH are functionality and appearance. Functionally, closed captioning is normally generated by the appliance (television set, DVD player, etc.), while SDH is encoded within the DVD disc and can be activated through the DVD menu.

Visually, closed captioning occurs as white text in a scrolling black box while SDH appears as text colored to contrast background images. SDH also features variations of text style to distinguish between actions, specific speakers, and associated dialog.

Recently, we’ve received calls regarding SDH. Primarily, customers are concerned they’re receiving product that is SDH only, meaning the title always has this feature turned on. To alleviate concerns, we thought we’d examine the evolution of SDH.

Due to limited storage and digital functionality, VHS products were unable to feature different versions of a title on a single tape. Therefore, vendors produced SDH-only versions of VHS titles, and libraries ordered these in addition to their normal VHS orders, much like they did with Spanish-dubbed versions of popular VHS titles.

Because increased memory space and digital functionality on DVDs and Blu-ray discs allow SDH to be stored as a menu option, like language or surround sound, libraries no longer need to purchase two versions of a title. Now, informed circulation staffs can educate patrons on how to enable the SDH feature on their DVD and Blu-ray materials rather than referring them to separate versions.

SDH on CVSMidwestTapes.ca
On our website we note the availability of the SDH feature within a title’s product details. We will make every effort to note SDH capabilities when we are aware of them.

The screenshot below shows the product details for the 2010 special edition Robin Hood DVD. Under “Miscellaneous” SDH availability is noted.

Click image to view larger size.