graph TD A[Start] --> B[Input YouTube URL] B --> C{Validate URL} C -->|Invalid| D[Error: Invalid URL] D --> B C -->|Valid| E[Generate Standard Filename] E --> F[Download YouTube as MP3] F --> G{Download Success?} G -->|No| H[Error: Download Failed] H --> B G -->|Yes| I[Convert MP3 to WAV] I --> J{Conversion Success?} J -->|No| K[Error: Conversion Failed] K --> F J -->|Yes| L[Save WAV File] L --> M[End: Return WAV Path]