# AAC to E-AC-3 Converter

Converts AAC 5.1/7.1 audio tracks to E-AC-3 while preserving all other streams (video, subtitles, metadata).

## Requirements

- Python 3.6+
- FFmpeg with E-AC-3 support

## Usage

```bash
# Preview conversions (recommended first step)
python aac2eac.py /path/to/media --dry-run

# Convert to new files (original.eac.mkv)
python aac2eac.py /path/to/media

# Overwrite original files (creates temporary backups)
python aac2eac.py /path/to/media --overwrite

# Custom FFmpeg path
python aac2eac.py /path/to/media --ffmpeg /usr/local/bin/ffmpeg
```

## Options

- `path` - Directory containing .mkv/.mp4 files (searches recursively)
- `--dry-run` - Show what would be converted without making changes
- `--overwrite` - Replace original files instead of creating new ones
- `--ffmpeg` - Path to FFmpeg binary (default: `ffmpeg`)

## What it does

- Scans directory for .mkv and .mp4 files
- Identifies AAC audio tracks with 6 channels (5.1) or 8 channels (7.1)
- Converts those tracks to E-AC-3:
  - 5.1 → 640 kbps
  - 7.1 → 1024 kbps
- Copies all other streams unchanged (video, subtitles, other audio)
- Preserves all metadata