# Dual Encoder Support - Implementation Complete ✅

## Features Added

The transcoder now supports switching between two video encoders via the `--encoder` CLI option:

### 1. **HEVC NVENC 10-bit** (Default)
- **Command**: `--encoder nvenc` or default (no flag needed)
- **Codec**: `hevc_nvenc`
- **Preset**: `slow` (high quality)
- **Bit Depth**: 10-bit
- **Pixel Format**: `yuv420p10le`
- **Use Case**: Best quality archival format, suitable for Plex compatibility

### 2. **AV1 NVENC 8-bit**
- **Command**: `--encoder av1`
- **Codec**: `av1_nvenc`
- **Preset**: `p7` (high quality)
- **Bit Depth**: 8-bit
- **Pixel Format**: `yuv420p`
- **Use Case**: Maximum file size reduction, modern playback devices

## Usage Examples

```bash
# Default to HEVC NVENC 10-bit with smart resolution scaling
python main.py "C:\Videos\Movies"

# Force AV1 NVENC 8-bit encoding
python main.py "C:\Videos\TV" --encoder av1

# AV1 with explicit resolution
python main.py "C:\Videos\Anime" --encoder av1 --r 1080

# AV1 with CQ mode at specific quality
python main.py "C:\Videos\Low-Res" --encoder av1 --cq 28

# AV1 with bitrate mode
python main.py "C:\Videos\Movies" --encoder av1 --m bitrate

# HEVC (explicit, though it's the default)
python main.py "C:\Videos\TV" --encoder nvenc --cq 26
```

## Configuration

Encoder settings are stored in `config.xml`:

```xml
<encoder default="nvenc">
  <av1_nvenc preset="p7" bit_depth="8" pix_fmt="yuv420p" />
  <hevc_nvenc preset="slow" bit_depth="10" pix_fmt="yuv420p10le" />
</encoder>
```

The `default="nvenc"` attribute can be changed, but CLI `--encoder` flag always takes precedence.

## Files Modified

1. **config.xml** - Added `<encoder>` section with both encoder configurations
2. **main.py** - Added `--encoder` argument, defaults to "nvenc"
3. **encode_engine.py** - Updated `run_ffmpeg()` to:
   - Accept `encoder` parameter
   - Dynamically set encoder codec, preset, bit depth, and pixel format
   - Display encoder details in logging output
4. **process_manager.py** - Updated to:
   - Accept and pass `encoder` parameter through processing pipeline
   - Updated both Phase 1 (initial encode) and Phase 2 (bitrate retry) encode calls

## Quality Notes

| Aspect | HEVC NVENC | AV1 NVENC |
|--------|-----------|----------|
| **File Size** | ~80-90% of AV1 | Smallest (baseline) |
| **Quality** | Excellent | Excellent |
| **Preset** | slow (p6) | p7 |
| **Bit Depth** | 10-bit | 8-bit |
| **Compatibility** | Excellent (Plex) | Good (modern devices) |
| **Encoding Speed** | Fast | Fast |

Both encoders use NVIDIA GPU acceleration (NVENC) for fast encoding.