# Understanding Tonemapping in Jellyfin

## What is Tonemapping?
Tonemapping converts HDR (High Dynamic Range) videos to look good on non-HDR screens. Think of it like your eyes adjusting when you walk from bright sunlight into a dimmer room - it helps balance bright and dark areas to make everything visible.

## Why Do I Need It?
If you have HDR content (like 4K HDR movies) but watch them on a non-HDR screen, without tonemapping:
- Bright areas might look washed out
- Dark areas might be too dark to see
- Colors might appear wrong or faded

## Available Algorithms

### hable
- **Best for**: Modern GPUs (NVIDIA RTX, AMD RX 6000+, Intel ARC)
- **What it does**: Makes HDR content look natural, similar to how your eyes adjust
- **Good for**: Movies and shows, especially ones with both bright and dark scenes
- **Example**: In a night scene with street lights, you'll see both the dark alleys and the bright lights clearly

### bt2390
- **Best for**: Integrated graphics (Intel iGPU, AMD APU) and older GPUs
- **What it does**: Follows TV industry standards for HDR conversion
- **Good for**: Broadcast content and professional productions
- **Example**: Makes your content look similar to how it would appear on a standard TV

### Other Options

#### reinhard
- **Pros**: Fast and simple, uses less processing power
- **Cons**: Can make dark scenes too dark
- **Best for**: Older hardware or when performance is a priority

#### mobius
- **Pros**: Keeps bright areas detailed
- **Cons**: Can make the overall image look flat
- **Best for**: Content with lots of bright scenes

## Which Should I Choose?

1. **For Modern GPUs**:
   - NVIDIA RTX Series: Use `hable` - excellent performance with good quality
   - AMD RX 6000/7000: Use `hable` - works well with modern AMD cards
   - Intel ARC: Use `hable` - optimized for ARC architecture

2. **For Integrated Graphics**:
   - AMD Ryzen APU: Use `bt2390` or try `hable` on newer models
   - Intel iGPU: Use `bt2390` (or `hable` on 11th gen or newer)

3. **For Older GPUs**:
   - NVIDIA GTX Series: Start with `bt2390`, try `reinhard` if needed
   - AMD RX 5000 or older: Use `bt2390` or `reinhard`
   - CPU's or Older integrated graphics: Use `reinhard` for best performance

## Quick Tips
- If videos look too dark: Try switching from bt2390 to hable
- If playback is stuttering: Try reinhard for better performance
- For best results: Enable hardware acceleration and use appropriate drivers:
  - NVIDIA: Latest drivers with NVENC support
  - AMD: Mesa or AMDGPU-PRO with VA-API
  - Intel: Latest drivers with QuickSync support

## CPU-Only Transcoding
If you're not using hardware acceleration (GPU/iGPU):

1. **Performance Impact**: Tonemapping is very CPU-intensive without hardware acceleration
2. **Recommended Settings**:
   - Use `reinhard` algorithm - it's the most CPU-efficient
   - Consider pre-converting HDR content to SDR if possible
   - Limit concurrent transcoding sessions
3. **CPU Requirements**:
   - Modern CPU (6+ cores recommended)
   - Expect high CPU usage during HDR transcoding
   - Multiple simultaneous HDR transcodes may not be possible

**Note**: If you have a modern Intel CPU with integrated graphics (iGPU), enabling hardware 
acceleration is strongly recommended, even if you don't have a dedicated GPU.