Updates to HDR and 4K video availability and production still image.

The iTunes Package Film Specification has been updated. Version 5.2.19 includes the following updates: 

HDR and 4K Video Availability 
New tags have been added to provide 4K and HDR availability. You can use the new tag <available_for_4k_date> to indicate when a HDR or 4K video will be available for sale on the iTunes Store for a given territory.

If you want to display the format for HDR video during the preorder period, you can use the new tag <hdr_format>. The value can be “hdr10” or “dolby_vision”. Only one format can be specified and once delivered, it cannot be updated. You should also include the <available_for_4k_date> tag if you want your movie to badge with 4K and/or HDR on the store. The date should match the pre-order date. 

Production Still Image 
You can now specify a frame to use for the production still image that will be displayed on the product page for a movie. Using the new tag <production_still_image_time> on the full asset, you can indicate the time to use to cut the image from the full asset. The image time must be within the full source with a 16:9 aspect ratio.

You can also deliver a separate production still image, but Apple prefers that you send the production still image cut from the full asset. If you deliver separately, the image dimensions must be 1920 x 1080 with a 16:9 aspect ratio.