HDR Tutorial for DUMMIES

Описание: Certainly! Let's delve into HDR content and explore how to convert HLG (Hybrid Log Gamma) videos into HDR (High Dynamic Range) videos.

Understanding HDR Content
HDR (High Dynamic Range) content enhances the visual experience by providing greater contrast, richer colors, and improved brightness. It allows viewers to see details in both dark and bright areas of an image or video. Here are some key points about HDR:

1. **Dynamic Range**: HDR expands the dynamic range beyond what standard content (SDR) can achieve. It captures more details in highlights and shadows, resulting in a more lifelike image.

2. **HDR Formats**:
**HDR10**: The most common HDR format. It uses static metadata and is widely supported by devices and streaming services.
**Dolby Vision**: A dynamic HDR format that adjusts scene-by-scene for optimal playback.
**HLG (Hybrid Log Gamma)**: Developed by the BBC and NHK, HLG is designed for broadcast and live content. It combines SDR and HDR information in a single signal.

3. **HLG Workflow**:
HLG content is captured using compatible cameras or camcorders.
When played on an HLG-compatible display, it automatically adjusts for HDR playback.
HLG is ideal for scenarios where real-time conversion to HDR is necessary (e.g., live broadcasts).

Converting HLG to HDR
Converting HLG videos to HDR involves adjusting the color space and gamma curve. Here are steps you can follow:

1. **Color Space Conversion**:
HLG videos are typically in the Rec. 2020 color space.
Convert the HLG video to the Rec. 709 color space (used for SDR content) during editing. This allows you to work with familiar color grading tools.

2. **Gamma Curve Adjustment**:
HLG uses a hybrid gamma curve that combines linear and logarithmic components.
Apply a gamma correction to transform the HLG gamma curve into the PQ (Perceptual Quantizer) curve used in HDR10.
Use tools like DaVinci Resolve or ffmpeg with LUTs (Look-Up Tables) for this conversion[^10^].

3. **Metadata Injection**:
Add HDR metadata (such as MaxFALL and MaxCLL) to the video file.
This metadata informs HDR displays about the content's peak brightness and overall luminance.

4. **Export and Distribution**:
Export the converted video in an HDR-compatible format (e.g., HEVC with 10-bit color depth).
Upload it to platforms like YouTube, which support HDR content.