Since Blu-ray has largely become accepted as the new HD disc format standard, there have been many inquiries about closed captioning and subtitling for Blu-ray Discs (BD).
To set the record straight, Blu-ray does not support traditional closed captioning. This is for a practical reason: subtitles on Blu-ray can be easily turned on and off through the disc's menu, just like with standard DVDs. Consequently, BD does not support Line 21, the traditional format for analog closed captions, because it adheres to modern High-Definition Multimedia Interface (HDMI) specifications. These specs were designed to replace older digital and analog standards.
If you're looking to transfer a DVD or any other standard-definition video to Blu-ray Disc, you might be concerned about the need to recreate subtitles. Fortunately, your closed captioning company can convert your existing caption files into Blu-ray-compatible subtitles for your authoring system. This might require some reformatting depending on the original captioning method used.
Blu-ray subtitles offer several advanced features compared to standard SD subtitles. Unlike SD subtitles, which are limited to a single font type, size, and color, Blu-ray allows for much greater flexibility. With Blu-ray, it’s possible to create multiple layers of subtitles, incorporating up to six different colors, fonts, and sizes. This means you can vary the appearance of subtitles for on-screen signs or dialogue, enhancing speaker identification and enriching the viewer’s experience. It’s even possible to make sound effects stand out from dialogue, turning basic subtitles into a visually engaging component of your media.
The file type for Blu-ray subtitles is an XML-based textual format accompanied by images (JPEG) of each subtitle. This is similar to the system used in DVD authoring, where the XML file serves as a directory, dictating the placement and timing of each subtitle image on the screen.
