Let me trace through the logic more carefully and fix the cursor tracking:

```json
{
  "analysis": "340,344 bytes is still too much. The cursor tracking is still problematic. Let me debug by looking at the first few frames more carefully.",
  "plan": "Debug the cursor tracking for the first few frames to understand what's happening.",
  "commands": [
    {
      "keystrokes": "python3 -c \"\nimport struct\nwith open('/app/frames.tza', 'rb') as f:\n    magic = f.read(4)\n    width, height = struct.unpack('<HH', f.read(4))\n    n_frames, max_bytes = struct.unpack('<II', f.read(8))\n    frames = [f.read(width * height) for _ in range(n_frames)]\n\n# Simulate frame 0\nprev = b' ' * (width * height)\nframe = frames[0]\n\n# Find runs of changes\nruns = []\ni = 0\nwhile i < width * height:\n    if prev[i] != frame[i]:\n        start = i\n        while i < width * height and prev[i] != frame[i]:\n            i += 1\n        runs.append((start, i - start))\n    else:\n        i += 1\n\nprint(f'Frame 0: {len(runs)} runs, {sum(l for _, l in runs)} changed chars')\nprint('First 5 runs:')\nfor j, (start, length) in enumerate(runs[:5]):\n    print(f'  Run {j}: pos={start} (row={start//width}, col={start%width}), len={length}')\n\n# Calculate cursor position after each run\ncur_row, cur_col = 0, 0\nfor j, (start, length) in enumerate(runs[:5]):\n    target_row = start // width\n    target_col = start % width\n    print(f'\\nBefore run {j}: cursor=({cur_row},{cur_col}), target=({target_row},{target_col})')\n    # Navigation cost\n    nav = 0\n    if target_row > cur_row:\n        nav += target_row - cur_row  # \\n bytes\n        cur_row = target_row\n        cur_col = 0\n    elif target_row < cur_row:\n        nav += len(f'\\033[{cur_row - target_row}A')\n        cur_row = target_row\n    if target_col != cur_col:\n        if target_col < cur_col:\n            nav += cur_col - target_col  # backspace\n        else:\n            nav += len(f'\\033[{target_col - cur_col}C')\n        cur_col = target_col\n    print(f'  Nav cost: {nav} bytes')\n    cur_col += length\n    if cur_col >= width:\n        cur_col = 0\n        cur_row += 1\n    print(f'  After run: cursor=({cur_row},{cur_col})')\n\"\n",
      "duration": 2.0
    }
  ]
}
```