Topics covered in this article:
- Components of Dolby Vision deliverables
- The Dolby Vision encoding process
Dolby Vision content can be delivered in a few different ways and this is usually dependent on the request from the studio that owns or commissions the project.
The most popular ways to deliver a Dolby Vision Master are as follows:
- 16-bit Tiff Image Sequence + Dolby Vision XML
- ProRes 4444 XQ + Dolby Vision XML
- Dolby Vision MXF mezzanine
- Dolby Vision IMF mezzanine
In each case, there will be a PQ-based HDR image/video component (Tiff, ProRes, Jpeg2000, etc.) and accompanying Dolby Vision metadata that may be embedded in the video essence (MXF, IMF, etc.) or delivered separately as a sidecar XML.
A mezzanine file is a compressed video file that is visually indistinguishable from the full-resolution master but smaller in size. It is usually used a 'service master' for creating different deliverables for distribution. A mezzanine is intended for ease of use and flexibility in distribution and mastering workflows and is usually of a lower quality (higher compression, lower bitrate) than an archival master.
The primary deliverables from the color correction system may require further mastering, versioning, etc. before they can be finally delivered to the studio or client.
There are a variety of products and solutions from Dolby’s partners that can be used to create versions or other deliverables like: HDR10, HLG, and SDR.
[refer to the article FAQ: Dolby Vision compatible Color Grading & Packaging Systems (force.com) for more information about supported systems and partner solutions]
The final versions have to be encoded before they can be sent to Dolby Vision consumer devices like televisions, tablets, or phones. Encoding usually involves converting the image/video essence into an HEVC/H265 bitstream and then muxing (multiplexing) that with Dolby Vision metadata and audio.
There are different ways to encode Dolby Vision content for distribution and playback on a consumer device.
1. Hardware-based encoders
They are usually the most reliable encoding solution that can be housed within a facility. They tend to be expensive and require considerable investment in human resources, power, ancillary infrastructure, etc.
2. Software-based encoders
Software-based encoders like Dolby’s DEE are cost-effective and scalable but require a substantial amount of hand-holding and manpower for implementation, operation, maintenance, and monitoring. DEE requires a separate HEVC encoder as it is not a feature that is supported within DEE.
3. Cloud-based encoders
These are probably the most efficient and fastest way to encode content today, as all the processing is done utilizing resources in the cloud.
The encoding process is used to generate multiple versions to cater to the different types of devices that are currently used to view and consume content.