ATSC Slowly Moving Toward HDR Broadcast Solution
January has now passed, and the Advanced Television Systems Committee (ATSC), which is developing the next ATSC 3.0 over-the-air broadcast TV system, revealed it has made a selection in the highly competitive HDR technique selection process that embraces several possible approaches and leaves open the door for additional ones to be added later.
Mark Richer, ATSC president, told HD Guru this week that “ATSC Technology Group 3 has approved a ballot to elevate A/341 Video-HEVC as a Proposed Standard. The document includes support for (Hybrid Log-Gamma) HLG, (Perceptual Quantization) PQ transfer functions and optional static metadata for PQ (HDR10 metadata). Additional HDR technologies are under consideration for inclusion in future revisions of A/341.”
Read more on the ATSC’s HDR format selection for ATSC 3.0 after the jump:
The ATSC has been considering five HDR technologies as future amendments to A/341, and each will be put up balloting as a candidate standard.
For much of the last year, the ATSC has been testing and considering a variety of technologies for live on-the-fly HDR broadcasting. Most of these techniques are based on the Perceptual Quantization (PQ) transfer function (ST.2084) developed with significant contributions from Dolby Labs, and currently used for both the HDR10 and Dolby Vision HDR systems applied to Ultra HD streaming and Ultra HD Blu-ray sources. Among the proposed live, or “Active,” HDR systems that have been considered in the process were those submitted by the following:
- Technicolor (transfer function agnostic)
- Dolby Labs (Perceptual Quantization-PQ-transfer function)
- Qualcomm (PQ transfer function)
- Qualcomm+Sharp+Samsung (PQ transfer function)
- Ericsson (PQ transfer function)
- NHK/BBC (Hybrid Log-Gamma transfer function)
Content supporting these formats will use dynamic range elements, which are captured by new digital cameras capable of recording 14 stops or more of light, and added to the final program in on-the-fly color grading. The ATSC’s video group has already approved use of the HEVC video compression codec, Main-10 profile, Main Tier, meaning the selected HDR system(s) must support that as well as be 10-bit compatible.
Of the two HDR systems in use for home entertainment today, Dolby Vision is optimized for dynamic metadata that will enable color grading on a frame-by-frame basis, as is required for live HDR broadcasts. However, Samsung demonstrated at CES 2017 that it is working on enhancements to HDR10, which would allow that technique’s current static metadata application that requires one set of color-grading parameters for an entire production to have dynamic metadata capabilities. The HDR10 and HLG systems are both open platforms.
The ATSC has said it is trying to avoid confusing consumers by allowing fragmented HDR solutions in the marketplace, and therefore the members are intent on specifying technologies adaptable to their unique environment that will be deployable on a large scale over various devices.
By Greg Tarr
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