As a video developer, you may find that there is a lack of systematic summaries on HDR-related information, and it feels like walking in the dark. I want to light a lamp and record and summarize good articles I come across in development to share with everyone. If you come across good articles, you can submit them on GitHub, maybe it will help a fellow developer.
If you find this information helpful, please give a thumbs up to the HDR to SDR open source code. Your encouragement is my greatest motivation to move forward.
| Name | Notes |
|---|---|
| Journey of HDR to SDR Conversion⭐ | This series explains HDR conversion theory in a simple and understandable way based on the problems encountered in development. Code repository: HDRSample🔥 |
| HDR in Android⭐ | Using 10-bit textures to reference ffmpeg for HDR to SDR conversion using OpenGL and hable tone mapping. |
| BT.2446 Method C (HDR to SDR Conversion)⭐ | Research on BT2446's C method, provides BT2446C, Youtube HDR to SDR LUT |
| MovieLabs_Mapping_PQ_to_HLG_v1.0⭐ | MovieLabs' practice of mapping PQ to HLG using the MaxRGB method. |
| Introduction to Android Game Development on Adreno GPU | How to implement true HDR playback using OpenGL. |
| Conversion between HLG and PQ Curves in HDR | Practical implementation of HLG and PQ formula conversion. |
| Name | Notes |
|---|---|
| HDRSample🔥 | Open source code for the Journey of HDR to SDR Conversion series. |
| hdrtoys⭐ | HDR to SDR plugin for the mpv player. |
| android⭐ | Tonemap in Android. |
| libplacebo tonemap⭐ | Tonemap for the mpv player. |
| ffmpeg | Tonemap in ffmpeg. |
| kodi | Tonemap in kodi. |
| gopro | Implementation of BT2446a tone mapping. |
| glsl-tone-map | Common tone mapping curves. |
| HDRTVNET | SDR to HDR conversion using deep learning. |
| OpenCV TMO | OpenCV's tone mapping. |
| Title | |
|---|---|
| Why is Color Space so Empty⭐ | Perhaps the best explanation of color space in Chinese videos. |
| Yaming's Column⭐ | Comprehensive explanation of BT2100 and BT2048 (reference white level, scene reference, display reference, comparison of HDR and SDR up-conversion and down-conversion). The column has 13 articles, or you can directly view the PPT. |
| Research and Application of Inverse Tone Mapping Algorithm in Film and Television Field⭐ | Summarizes various inverse tone mapping algorithms in SDR to HDR conversion. |
| Talking about HDR and Color Management⭐ | Step-by-step explanation of HDR in games starting from color space. |
| HDR in Call of Duty | HDR in Call of Duty. |
| HDR Hardware Imaging Technology | HDR Imaging Technology Study (Part 1) HDR Imaging Technology Study (Part 2) HDR Imaging Technology Study (Part 3) |
| Tone Curve Summary | HDR Tone Mapping tonemapping local-tonemapping |
| Name | Notes |
|---|---|
| Technical Implementation of SDR to HDR Conversion at Qiniu Cloud | Introduces the SDR to HDR tone mapping formula, chroma enhancement formula, and detail preservation method at Qiniu Cloud. |
| Tencent's SDR to HDR Sharing | Explanation of the SDR to HDR up-conversion solution. |
| MicroFrame HDR Sharing | Enhances contrast in different regions of a video frame before transcoding, achieving an SDR with HDR appearance. |
| Kuaishou HDR Video Generation Algorithm Sharing & Research Paper | 1. Uses the HDCFM (Hierarchical Dynamic Context Feature Mapping) model for enhancing dark parts and suppressing highlights in video frames. 2. Uses the PDCG (Patch Discriminator for Highlight Generation) model for generating highlights in HDR video frames. |
| Kuaishou HDR to SDR Sharing | Provides an introduction to HDR video characteristics, brightness perception model, and what Kuaishou does in hybrid editing between SDR and HDR. |
| Weibo HDR Sharing | Introduces HDR video characteristics and the transformation made to Weibo's video pipeline. |
| Xigua Video HDR Sharing | Introduces the solution for HDR video uploading, transcoding, distribution, and terminal playback in Xigua Engine Lab. |
| OPPO HDR Sharing | Introduces HDR video characteristics and the industry ecosystem of OPPO. |
| Baidu HDR Sharing | Introduces Baidu's application of intelligent super-clear HDR. |
| Huawei Cloud Video AI Transcoding Area Sharing | Introduces Huawei Cloud's technical practices in image enhancement and SDR to HDR conversion. |
| Taobao Audio and Video Algorithm Sharing | Introduces Alibaba's self-developed APG high compression ratio image format, H.265 implementation and optimization, high-definition transcoding, HDR10 end-to-end playback, self-developed AliDenoise intelligent noise reduction, and TaoAudio audio solution. |
| Name | Notes |
|---|---|
| BT1886 | Defines the transfer function for CRT displays in BT1886. |
| BT709 | Defines the BT709 color space for high-definition video. |
| BT2020 | Defines the BT20202 color space for ultra high-definition video. |
| BT2087⭐ | 1. Provides a method for direct mapping from BT709 to BT2020. 2. Compares scene mapping and display mapping. |
| BT2100 | Extends BT2020 with PQ and HLG transfer functions. |
| BT2111 | PQ and HLG color bar test pattern specifications. |
| BT2250 | Deriving color conversion matrices |
| BT2390⭐ | 1. Supplementary explanation of BT2100 PQ and HLG transfer functions. 2. Comparison of YCBCR and ICTCP color handling. |
| BT2407⭐ | 1. How to use lab to complete tone, brightness, and chromaticity mapping to avoid saturation and chromaticity problems caused by direct mapping from BT2020 to BT709. 2. A method for BT2020 to BT709 soft clipping using luv. |
| BT2408⭐ | 1. HDR TV production practice guide 2. Redefines reference white levels for BT2100 PQ and HLG. 3. How to lower PQ brightness through the EETF function. 4. Direct mapping methods for SDR to HDR conversion. 5. Methods for PQ to HLG and HLG to PQ conversions. |
| BT2446 | Three dynamic mapping methods for converting between HDR and SDR. |
| ST2084 | Defines the PQ OETF transfer function. |
| ST2086 | Defines HDR static metadata. |
| ST2094 | Defines HDR dynamic metadata. ST 2094-1 ST 2094-2 ST 2094-10 ST 2094-20 ST 2094-30 ST 2094-40 |
| SL-HDR | Another HDR standard besides HLG and PQ. SL-HDR1 SL-HDR2 SL-HDR3 |
| Khronos Data Format Specifications | PQ and HLG transfer function formulas compiled in Khronos' documentation. |
| Title | Notes |
|---|---|
| Technical Requirements for High Dynamic Range Television System Display Adaptation Metadata⭐ | SARFT's definition of HDR metadata in video for H.265. |
| Research and Testing on Standard Dynamic Range and High Dynamic Range Conversion Methods⭐ | Testing and research on the direct mapping conversion of HDR and SDR proposed by BT2087 and BT2390. |
| Guidelines for 4K Ultra High Definition Television Program Production 2020 Edition | SARFT's practical guide on BT2408. Considerations in HDR production. Reference white levels at 75% HLG, 58% PQ. |
| CCTV HDR Video Production White Paper 2022 Edition | SARFT's practical guide on BT2408. Considerations in HDR production. Common skin tone brightness. Level mapping relationship for HLG to SDR conversion. LUT for HLG to SDR conversion (LUT file not found). |
| Image Parameter Values for High Dynamic Range Television Program Production and Exchange | SARFT's explanation of BT2309, defining the transfer functions for PQ and HLG. |
| Ultra High Definition High Dynamic Range Video System Color Bar Test Pattern | SARFT's explanation of the color bar defined in BT2111. |
LUTs for Direct HDR-to-SDR Conversion
| Name | Notes |
|---|---|
| NBCU Open Source HDRLUT⭐ | NBCU_SDR2HLG_DL_v1.1.cube NBCU_SDR2HLG_SL_v1.cube NBCU_HLG2SDR_DL_v1.1.cube NBCU_SDR2PQ_DL_v1.cube NBCU_PQ2SDR_DL_v1.cube NBCU-HLG2PQ_1000nit_v1.cube |
| Linear Transformation⭐ | Linear color space transformations, includes conversions between BT2020 PQ, BT2020 HLG, and BT709. |
| Name | Notes |
|---|---|
| HDRVideo | Collection of 10 commonly used HDR videos. |
| Mehanik HDR10 Test Patterns⭐ | Grayscale, hue, dithering, white level, black level test videos. |
| tfb-video Test Video Generation Code⭐ | Code to generate test videos. Video Links |
| ARIB STD-B72 Color Bar Video Code | Color bar test video generated based on ARIB STD-B72. Adding a waveform monitor allows for accurate color matching. ARIB STD-B72 Colour Bar Test Pattern for HLG |
| BT2111-DV | Dolby Vision Profile 5 color bar test video modified according to BT2111. Adding a waveform monitor allows for accurate color matching. BT2111-MOD_DV5_UHD_24P.mp4 |
| Kodi Test Videos⭐ | HDR 10-bit HEVC 25fps HDR 10-bit Grayscale Rotating Gradients HDR10 HEVC 59.94 HDR10+ Profile A HEVC 10-bit 23.976 Sample HDR10+ Profile B HEVC 10-bit 23.976 Sample HDR10+ Dynamic Metadata Test 60fps |
| TV Test Videos | Television screen test videos. |
| DisplayHDRTest⭐ | Test HDR display and video color standards. |
| Name | Notes |
|---|---|
| Color Space Calculator⭐ | Online color space conversion matrix calculator. |
| Rainbow Space | Visualization of color space in images. |
| Color Converter | Online color conversion tool. |
| Colour | Python package for color science algorithms. |
| XYZ Color Space Visualization | Visualization of the XYZ color space. |