Filter Graph Naming Conventions

This rule applies to files matching the patterns above.

# Filter Graph Naming Conventions

## Rule
All FFmpeg complex filter graphs MUST use named pads, one filter per line for readability, and include comments documenting the filter purpose.

## Pad Naming Convention
```bash
# Use descriptive names for filter pads
# Format: [type_description] — e.g., [v_scaled], [a_normalized], [overlay_result]

# Good — named and readable
ffmpeg -i main.mp4 -i watermark.png -filter_complex "
  [0:v]scale=1920:1080[v_scaled];
  [v_scaled][1:v]overlay=W-w-10:H-h-10[v_watermarked]
" -map "[v_watermarked]" -map 0:a output.mp4

# Bad — unnamed and cramped
ffmpeg -i main.mp4 -i wm.png -filter_complex "[0:v]scale=1920:1080[a];[a][1:v]overlay=W-w-10:H-h-10[b]" -map "[b]" -map 0:a out.mp4
```

## Formatting Rules
```bash
# Rule 1: One filter per line for complex graphs
# Rule 2: Align input/output pads vertically
# Rule 3: Use descriptive pad names, not [a], [b], [c]
# Rule 4: Add comments for non-obvious operations

ffmpeg -i input.mp4 -i overlay.png -i logo.png \
  -filter_complex "
    [0:v]scale=1920:1080[v_base];
    [v_base][1:v]overlay=10:10:enable='between(t,5,15)'[v_with_overlay];
    [v_with_overlay][2:v]overlay=W-w-10:10[v_final]
  " \
  -map "[v_final]" -map 0:a \
  -c:v libx264 -crf 22 \
  output.mp4
```

## Good Pad Names
```
[v_scaled]       — video after scaling
[v_cropped]      — video after cropping
[v_watermarked]  — video with watermark applied
[a_normalized]   — audio after loudness normalization
[v_final]        — final video output
```

## Bad Pad Names
```
[a] [b] [c]      — meaningless
[out1] [out2]    — no context
[tmp] [temp]     — undescriptive
[x] [y] [z]     — random letters
```

## Anti-Patterns
- Single-line complex filter graphs (unreadable beyond 2 filters)
- Unnamed pads [a], [b], [c] (impossible to debug)
- No comments on non-obvious filter operations
- Mixing simple (-vf) and complex (-filter_complex) syntax
- Not testing with -t 10 before full processing