How Kuaishou Enables Full‑Chain Dolby Vision Support for UGC

Kuaishou and Dolby Labs Deep Collaboration

Kuaishou announced a partnership with Dolby Labs to support Dolby Vision video format on its platform, allowing users to watch and share Dolby Vision content.

What Is Dolby Vision?

Dolby Vision is a high‑dynamic‑range (HDR) imaging technology developed by Dolby Labs that combines HDR with a wide color gamut, using dynamic metadata to optimize brightness and color on a per‑frame basis. It supports 10‑bit and 12‑bit color depth, delivering richer colors and higher contrast than standard SDR video.

Full‑Chain Support Implementation

Kuaishou’s technical team upgraded the entire video processing pipeline to enable Dolby Vision for user‑generated content (UGC), covering:

Video publishing: supports direct, unedited, and edited publishing of Dolby Vision videos.

Media asset management: accurate identification and handling of Dolby Vision assets.

Quality evaluation: objective assessment service now supports Dolby Vision.

Transcoding: retains Dolby Vision metadata and adds new transcoding profiles.

Playback experience: client‑side playback with adaptive downgrade for devices, and Dolby Vision logo overlay.

The platform uses Dolby Vision Profile 8.4, based on HLG and HEVC, optimized for mobile UGC scenarios.

Brightness Dynamic Adjustment Solution

To ensure a smooth viewing experience, Kuaishou introduced an extended brightness adjustment scheme that dynamically adapts video brightness to the device’s screen brightness, providing natural transitions from SDR to Dolby Vision and preventing UI elements from appearing dim in HDR scenes.

Challenges When Viewing Dolby Vision

Two main issues arise when HDR and SDR content coexist: HDR video can appear overly bright compared to SDR, and SDR UI elements (e.g., icons, text) may look gray‑ish against the bright HDR background, affecting readability.

iOS Extended Dynamic Range (EDR)

iOS defines EDR headroom as screen peak brightness / SDR reference white , establishing brightness ranges for SDR ([0.0, 1.0]) and HDR ((1.0, EDR headroom]).

Using the HLG_EOTF (Rec. 2100 HLG) standard, Kuaishou dynamically scales the portion of the signal above SDR white based on current screen brightness, then performs tone‑mapping before display.

Results

The dynamic brightness feature, implemented with Metal on iOS, significantly increased the proportion of users enabling the extended brightness effect when watching Dolby Vision videos.

By integrating advanced imaging technology, Kuaishou enhances content quality, attracts creators, and drives industry innovation.