User:SH4ever/HDR meanings and writing

(The following is my personnal opinion. We can discuss it if you want).

HDR stands for:


 * High Dynamic Range
 * high dynamic range

Multiple topics related to images and videos are refered by these terms. They are distinct despite sharing the same name and being related to the same area (images and videos). This is confusing and led to misunderstanding inside and outside Wikipedia.

Here are explanations.

Overview
In imaging, High Dynamic Range (HDR) may refer to:


 * HDR (color representation), a way of representing videos (or images) that is related to displays and that allow for a higher luminance, higher dynamic range and wider color gamut than the previous standard color representation (SDR)
 * HDR format, for example HDR10, Dolby Vision, HDR10+, HLG
 * HDR display, a display compatible with an HDR format
 * HDR video, a video recorded in an HDR format
 * HDR image, an image recorded in an HDR compatible format
 * HDR camera, a camera that can capture videos or photos in an HDR format
 * HDR game, a game compatible with HDR display
 * HDR imaging, refers to the capture or the creation of images (or videos) with more dynamic range than usual
 * HDR (capture technique), a photography and videography technique that allow to capture photos (or videos) with an increased dynamic range
 * Computational HDR, a term used for the HDR capture technique when the process is done by computer (computational photography)
 * HDR image, an image that has been captured with the HDR capture technique
 * HDR video, a video that has been captured with the HDR capture technique
 * HDR camera, a camera that can do computational HDR (can capture photos or videos with the HDR capture technique)
 * HDR Rendering
 * HDR game, a game that use HDR rendering
 * High dynamic range format, an image or video format that can save images or videos with a higher dynamic range than the standard 8-bit gamma file format (for example: raw formats, log formats)
 * High dynamic range camera, a camera with a dynamic range higher than usual cameras

Definition

 * Page A refers to the dynamic range
 * Page B is about a technique
 * Page C is about a way of representing light and colors

Precision:


 * For topic A, "high dynamic range" means that the dynamic range is high. That doesn't really give a lot more info other than "beautiful light".
 * For topic B, "HDR" means the technique which consist of the capture of multiple images with different exposures and the merging of this images. We can do that to capture still photos and also videos. It's a technique that expands the capability of our camera to capture the real world.
 * For topic C, "HDR" doesn't mean any "way of representing light and colors", it means the one that respect BT.2100 and might also use or not use some specific metadata to form formats such as HDR10, Dolby Vision, HDR10+, PQ10 and HLG10. Topic C is about a specific format that is made for displays. It doesn't include the high dynamic range formats such as log formats, raw formats and similar. One other important aspects of topic-C-HDR is that it's not only about dynamic range despite its name. ITU clearly state that in the section "Common misconceptions on HDR" of the Report 2390.
 * In technical terms, topic C refers to anew color space (BT.2100) and everything surrounding that color space. Note that a lot of people do only understand color space in 2D (chromaticity) while its full meaning also include luminance. The 3D representation of color space is refered as a color volume. Topic-C HDR is a high color volume technology. Dolby Vision and HDR10+ metadata tell how the color volume of the content should be adjusted to match the color volume of the display.

Additionnal explanations

 * There is a book named "High dynamic range video, from acquisition to display and application" (2016). This book is about everything related to high dynamic range imaging for video. If you read it, you will see that here the term "high dynamic range video" is used with the meaning A and the books cover many things include topic B, parts of topic C and also other topics. High dynamic range video is a larger subject than topic C..

Common current uses vs all coming uses

 * Topic C is not only about video as you can see in this draft page. For now (2021), it's the most common for videos and games but it's comming for every digital graphics including still images and web pages. (For example some recent Sony, Canon and Panasonic cameras allow photographers to use it for photo capture).
 * Topic B is not only about photo capture as you can see on the "Videography" section of this page. For now (2021), this HDR technique is mainly used for capturing photos but thanks to technological achievements, it's now also possible to use it for capturing videos.

Other misleadings include the confusion of topic A and topic B. For example, "HDR Rendering" should go in page A instead of page B.

Interconnection
Cameras can use topic B to capture better photos and videos and topic C to store the captures photos and videos in a format which will allow to display them in a more beautiful way. If we look at the whole process, we can call this "high dynamic range imaging from acquisition to display" with the meaning of topic A. (Do not forget topic C also offer other things than displaying beautiful dynamic range).

For example:


 * The Xiaomi Mi 11 Ultra is able to do both B and C for video capture.
 * Some newer Canon, Sony and Panasonic cameras are able to do both B and C for photo capture.
 * Qualcomm Snapdragon 888 is able to do both B and C for both video and photo capture.

You can read more about that here and here. You also will find the sources.

Capitalization and acronym: 'HDR' vs 'High Dynamic Range' vs 'high dynamic range'
Correct use of capitalization and acronym:


 * Topic A: high dynamic range
 * Topic B: HDR or High Dynamic Range
 * Topic C: HDR or High Dynamic Range

For the other forms:


 * Topic A: We should never use other forms if we are talking about the meaning A.
 * Topic B: I believe a correct writing should avoid "high dynamic range" for topic B but for the moment I need to learn more about it to be completely sure.
 * Topic C: We shoupd never use "high dynamic range" without capitalization when we are specifically talking about topic C.

How is it written in the sources?


 * Topic C: Here are reliable sources that uses "High Dynamic Range" and "Wide Color Gamut" with capitalization when they are specifically refering to topic C:    . You might found some journalists who use it without capitalization but they just aren't as much aware as the industry's experts. They are not reliable sources for this subject.

Other similar use of capitalization:


 * HEVC: High Efficiency Video Coding
 * AVC: Advanced Video Coding
 * HEIF: High Efficiency Image File Format
 * AVIF: AV1 Image File Format
 * PNG: Portable Network Graphics

Acronym:


 * Topic A: The acronym HDR is not common when refering to the meaning A.
 * Topic B: Both forms can be used but the subject is the most known by its acronym HDR.
 * Topic C: Both forms can be used but the subject is the most known by its acronym HDR.

Usefulness:


 * It's the correct writing
 * When you see the term "HDR" or "High Dynamic Range", you know for sure this is either about topic B or topic C (unless the terms have been wrongly used).
 * It's important that Wikipedia promote the correct terminology. It improves understarding of the subject and help solving ambiguity and misconceptions.