FFmpeg extension is not available.

### Custom Node Testing

- [x] I have tried disabling custom nodes and the issue persists (see [how to disable custom nodes](https://docs.comfy.org/troubleshooting/custom-node-issues#step-1%3A-test-with-all-custom-nodes-disabled) if you need help)

### Expected Behavior

ComfyUI should execute successfully.
Actual configurtation:

- Debian 13
- ffmpeg version 7.1.2-0+deb13u1 Copyright (c) 2000-2025 the FFmpeg developers built with gcc 14 (Debian 14.2.0-19)
$ nvidia-smi
Wed Nov 19 17:28:15 2025
+-----------------------------------------------------------------------------------------+
| NVIDIA-SMI 580.105.08 Driver Version: 580.105.08 CUDA Version: 13.0 |
+-----------------------------------------+------------------------+----------------------+
| GPU Name Persistence-M | Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap | Memory-Usage | GPU-Util Compute M. |
| | | MIG M. |
|=========================================+========================+======================|
| 0 NVIDIA GeForce RTX 3060 On | 00000000:02:00.0 Off | N/A |
| 0% 43C P8 18W / 170W | 217MiB / 12288MiB | 0% Default |
| | | N/A |
+-----------------------------------------+------------------------+----------------------+
| 1 Quadro P4000 On | 00000000:03:00.0 Off | N/A |
| 46% 30C P8 5W / 105W | 5MiB / 8192MiB | 0% Default |
| | | N/A |
+-----------------------------------------+------------------------+----------------------+

### Actual Behavior

the execution stops right after : Using pytorch attention

### Steps to Reproduce

$ comfy launch

### Debug Logs

```powershell
$comfy launch -- --verbose

Launching ComfyUI from: /home/near/git/ComfyUI

[START] Security scan
[DONE] Security scan
Popen(['git', 'version'], cwd=/home/near/git/ComfyUI, stdin=None, shell=False, universal_newlines=False)
Popen(['git', 'version'], cwd=/home/near/git/ComfyUI, stdin=None, shell=False, universal_newlines=False)
## ComfyUI-Manager: installing dependencies done.
** ComfyUI startup time: 2025-11-19 17:25:13.524
** Platform: Linux
** Python version: 3.13.5 (main, Jun 25 2025, 18:55:22) [GCC 14.2.0]
** Python executable: /home/near/git/comfy-env/bin/python3
** ComfyUI Path: /home/near/git/ComfyUI
** ComfyUI Base Folder Path: /home/near/git/ComfyUI
** User directory: /home/near/git/ComfyUI/user
** ComfyUI-Manager config path: /home/near/git/ComfyUI/user/default/ComfyUI-Manager/config.ini
** Log path: /home/near/git/ComfyUI/user/comfyui.log

Prestartup times for custom nodes:
1.8 seconds: /home/near/git/ComfyUI/custom_nodes/ComfyUI-Manager

Checkpoint files will always be loaded safely.
Total VRAM 11908 MB, total RAM 7854 MB
pytorch version: 2.6.0+cu124
Set vram state to: NORMAL_VRAM
Device: cuda:0 NVIDIA GeForce RTX 3060 : cudaMallocAsync
Enabled pinned memory 7461.0
Using pytorch attention
Loading FFmpeg6
Failed to load FFmpeg6 extension.
Traceback (most recent call last):
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torio/_extension/utils.py", line 116, in _find_ffmpeg_extension
ext = _find_versionsed_ffmpeg_extension(ffmpeg_ver)
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torio/_extension/utils.py", line 108, in _find_versionsed_ffmpeg_extension
_load_lib(lib)
~~~~~~~~~^^^^^
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torio/_extension/utils.py", line 94, in _load_lib
torch.ops.load_library(path)
~~~~~~~~~~~~~~~~~~~~~~^^^^^^
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torch/_ops.py", line 1357, in load_library
ctypes.CDLL(path)
~~~~~~~~~~~^^^^^^
File "/usr/lib/python3.13/ctypes/__init__.py", line 390, in __init__
self._handle = _dlopen(self._name, mode)
~~~~~~~^^^^^^^^^^^^^^^^^^
OSError: libavutil.so.58: cannot open shared object file: No such file or directory
Loading FFmpeg5
Failed to load FFmpeg5 extension.
Traceback (most recent call last):
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torio/_extension/utils.py", line 116, in _find_ffmpeg_extension
ext = _find_versionsed_ffmpeg_extension(ffmpeg_ver)
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torio/_extension/utils.py", line 108, in _find_versionsed_ffmpeg_extension
_load_lib(lib)
~~~~~~~~~^^^^^
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torio/_extension/utils.py", line 94, in _load_lib
torch.ops.load_library(path)
~~~~~~~~~~~~~~~~~~~~~~^^^^^^
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torch/_ops.py", line 1357, in load_library
ctypes.CDLL(path)
~~~~~~~~~~~^^^^^^
File "/usr/lib/python3.13/ctypes/__init__.py", line 390, in __init__
self._handle = _dlopen(self._name, mode)
~~~~~~~^^^^^^^^^^^^^^^^^^
OSError: libavutil.so.57: cannot open shared object file: No such file or directory
Loading FFmpeg4
Failed to load FFmpeg4 extension.
Traceback (most recent call last):
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torio/_extension/utils.py", line 116, in _find_ffmpeg_extension
ext = _find_versionsed_ffmpeg_extension(ffmpeg_ver)
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torio/_extension/utils.py", line 108, in _find_versionsed_ffmpeg_extension
_load_lib(lib)
~~~~~~~~~^^^^^
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torio/_extension/utils.py", line 94, in _load_lib
torch.ops.load_library(path)
~~~~~~~~~~~~~~~~~~~~~~^^^^^^
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torch/_ops.py", line 1357, in load_library
ctypes.CDLL(path)
~~~~~~~~~~~^^^^^^
File "/usr/lib/python3.13/ctypes/__init__.py", line 390, in __init__
self._handle = _dlopen(self._name, mode)
~~~~~~~^^^^^^^^^^^^^^^^^^
OSError: libavutil.so.56: cannot open shared object file: No such file or directory
Loading FFmpeg
Failed to load FFmpeg extension.
Traceback (most recent call last):
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torio/_extension/utils.py", line 116, in _find_ffmpeg_extension
ext = _find_versionsed_ffmpeg_extension(ffmpeg_ver)
File "/home/near/git/comfy-env/lib/python3.13/site-packages/torio/_extension/utils.py", line 106, in _find_versionsed_ffmpeg_extension
raise RuntimeError(f"FFmpeg{version} extension is not available.")
RuntimeError: FFmpeg extension is not available.
```

### Other

_No response_