Previous response had warnings:
WARNINGS: - Extra text detected before JSON object
- Extra text detected after JSON object

New Terminal Output:

root@d7299c7f5982:/app# python3 -c "
> import struct
> with open('/app/frames.tza', 'rb') as f:
>     magic = f.read(4)
>     width, height = struct.unpack('<HH', f.read(4))
>     n_frames, max_bytes = struct.unpack('<II', f.read(8))
>     frames = [f.read(width * height) for _ in range(n_frames)]
>
> # Simulate frame 0
> prev = b' ' * (width * height)
> frame = frames[0]
>
> # Find runs of changes
> runs = []
> i = 0
> while i < width * height:
>     if prev[i] != frame[i]:
>         start = i
>         while i < width * height and prev[i] != frame[i]:
>             i += 1
>         runs.append((start, i - start))
>     else:
>         i += 1
>
> print(f'Frame 0: {len(runs)} runs, {sum(l for _, l in runs)} changed chars')
> print('First 5 runs:')
> for j, (start, length) in enumerate(runs[:5]):
>     print(f'  Run {j}: pos={start} (row={start//width}, col={start%width}), len={length}')
>
> # Calculate cursor position after each run
> cur_row, cur_col = 0, 0
> for j, (start, length) in enumerate(runs[:5]):
>     target_row = start // width
>     target_col = start % width
>     print(f'\nBefore run {j}: cursor=({cur_row},{cur_col}), target=({target_row},{target_col})')
>     # Navigation cost
>     nav = 0
>     if target_row > cur_row:
>         nav += target_row - cur_row  # \n bytes
>         cur_row = target_row
>         cur_col = 0
>     elif target_row < cur_row:
>         nav += len(f'\033[{cur_row - target_row}A')
>         cur_row = target_row
>     if target_col != cur_col:
>         if target_col < cur_col:
>             nav += cur_col - target_col  # backspace
>         else:
>             nav += len(f'\033[{target_col - cur_col}C')
>         cur_col = target_col
>     print(f'  Nav cost: {nav} bytes')
>     cur_col += length
>     if cur_col >= width:
>         cur_col = 0
>         cur_row += 1
>     print(f'  After run: cursor=({cur_row},{cur_col})')
> "
Frame 0: 140 runs, 901 changed chars
First 5 runs:
  Run 0: pos=0 (row=0, col=0), len=12
  Run 1: pos=13 (row=0, col=13), len=1
  Run 2: pos=15 (row=0, col=15), len=9
  Run 3: pos=25 (row=0, col=25), len=6
  Run 4: pos=32 (row=0, col=32), len=5

Before run 0: cursor=(0,0), target=(0,0)
  Nav cost: 0 bytes
  After run: cursor=(0,12)

Before run 1: cursor=(0,12), target=(0,13)
  Nav cost: 4 bytes
  After run: cursor=(0,14)

Before run 2: cursor=(0,14), target=(0,15)
  Nav cost: 4 bytes
  After run: cursor=(0,24)

Before run 3: cursor=(0,24), target=(0,25)
  Nav cost: 4 bytes
  After run: cursor=(0,31)

Before run 4: cursor=(0,31), target=(0,32)
  Nav cost: 4 bytes
  After run: cursor=(0,37)
root@d7299c7f5982:/app#
