- commit
- f1cfd10c1a605d3790d97028e9c40b4b13a9feb9
- parent
- c750e26c7e5021107e88b9c72940524bf2dbc2d3
- Author
- Tobias Bengfort <tobias.bengfort@posteo.de>
- Date
- 2025-08-10 14:29
tweaks
Diffstat
| M | _content/posts/2025-06-23-loudness/index.md | 4 | ++-- |
| M | _content/posts/2025-07-18-hdr/index.md | 27 | +++++++++++++++------------ |
2 files changed, 17 insertions, 14 deletions
diff --git a/_content/posts/2025-06-23-loudness/index.md b/_content/posts/2025-06-23-loudness/index.md
@@ -6,7 +6,7 @@ description: "Dialogue in a movie is barely audible, but explosion are far too l 6 6 --- 7 7 8 8 You know the situation: Dialogue in a movie is barely audible, so you turn the9 -1 volume all the way up. The next scene has an explosion and your ears explode.-1 9 volume all the way up. The next scene has an car crash and your ears explode. 10 10 11 11 To prevent this, there are algorithms to normalize loudness. I wasn't really 12 12 interested in reading everything there is to know about loudness normalization @@ -249,7 +249,7 @@ RLB performs even better than that. 249 249 250 250 In addition to the frequency weighting curve, ITU-R BS.1770-S also specifies an 251 251 algorithm to calculate "gated" loudness. In this version, power is calculated252 -1 as the average over many small chunks. Chunks that are too quite are ignored.-1 252 as the average over many small chunks. Chunks that are too quiet are ignored. 253 253 254 254 On top of this, [EBU Tech 255 255 3341](https://tech.ebu.ch/files/live/sites/tech/files/shared/tech/tech3341.pdf)
diff --git a/_content/posts/2025-07-18-hdr/index.md b/_content/posts/2025-07-18-hdr/index.md
@@ -17,8 +17,8 @@ were referring to the wider goal of having more details in shadows and 17 17 highlights. A higher dynamic range is one piece of the puzzle, but not all of 18 18 it. 19 1920 -1 In this post I will explore of some of the other changes that contribute to21 -1 that goal.-1 20 In this post I will explore some of the other changes that contribute to that -1 21 goal. 22 22 23 23 ## More Bits 24 24 @@ -84,12 +84,12 @@ game engines produce an extremely high dynamic range). 84 84 One option is to clip everything that cannot be displayed to the target space. 85 85 Since clipping individual channels might change the hue, sometimes people opt 86 86 to reduce the saturation instead. Another option is to shrink down the entire87 -1 space until it fits.-1 87 color space until it fits. 88 88 89 89 Which option you choose depends on your specific use case. [ICC 90 90 profiles](https://www.color.org/icc_specs2.xalter) (a file format for 91 91 conversion between color spaces) therefore can contain multiple mappings with92 -1 different rendering intents.-1 92 different *rendering intents*. 93 93 94 94 A special kind of tone mapping is *local tone mapping*, where the mapping is 95 95 different depending on context. For example, a dark pixel in a bright area of @@ -110,6 +110,9 @@ only take power away from users, it would also disregard the huge influence 110 110 that viewing conditions have on human sight. If anything, we need more options 111 111 for personalization, not less. 112 112 -1 113 I am not entirly sure if this is really what the authors of that specification -1 114 had in mind though. -1 115 113 116 ## Scene-to-Scene differences 114 117 115 118 [ITU-R BT.2390](https://www.itu.int/pub/R-REP-BT.2390/) mentions that a higher @@ -122,17 +125,17 @@ the next bright scene arrives. 122 125 123 126 ## Is any of this relevant? 124 127125 -1 A lot of work is currently being put into supporting HDR across the stack. On-1 128 A lot of work is currently being put into supporting HDR. On 126 129 the hardware side we need cameras that can capture more details and screens 127 130 that can display them. On the software side we need support for different color128 -1 spaces across the stack. Many image and video formats have already added that,129 -1 [CSS color Level 4](https://www.w3.org/TR/css-color-4/) brings more color130 -1 spaces to the web, and Wayland also recently gained a [color management-1 131 spaces across the stack. Many image and video formats have already been -1 132 adapted, [CSS color Level 4](https://www.w3.org/TR/css-color-4/) brings more -1 133 color spaces to the web, and Wayland recently gained a [color management 131 134 protocol](https://wayland.app/protocols/color-management-v1). 132 135 133 136 While I think that it is nice to have the option of a higher dynamic range and 134 137 a wider gamut (especially during production), sRGB is fine for most135 -1 everyday activity. Adding color management across the stack adds a whole lot of-1 138 everyday activity. Adding color management everywhere adds a whole lot of 136 139 complexity. 137 140 138 141 What I would like to see is better images and more personalization. What I fear @@ -140,7 +143,7 @@ we will get is less personalization and more scene-to-scene differences. 140 143 141 144 ## Further Reading 142 145143 -1 - The wayland ecosystem collected some information around HDR, among them a [list of all relevant specification](https://gitlab.freedesktop.org/pq/color-and-hdr/-/blob/main/doc/specs.md).144 -1 - [SMPTE RP 177](https://pub.smpte.org/pub/rp177/rp0177-1993_stable2010.pdf) explains how calculate a conversion matrix from primaries and white point-1 146 - The Wayland ecosystem collected some information around HDR, among other things a [list of all relevant specification](https://gitlab.freedesktop.org/pq/color-and-hdr/-/blob/main/doc/specs.md). -1 147 - [SMPTE RP 177](https://pub.smpte.org/pub/rp177/rp0177-1993_stable2010.pdf) explains how to calculate a conversion matrix from primaries and white point. 145 148 - The kernel documentation has a surprisingly good [explanation of color spaces](https://www.kernel.org/doc/html/v4.9/media/uapi/v4l/colorspaces.html).146 -1 - Matt Taylor has a good [article on tone mapping in games](https://64.github.io/tonemapping/) with lots of screen shots for comparison.-1 149 - Matt Taylor has a good [article on tone mapping in games](https://64.github.io/tonemapping/) with lots of screen shots.