统计TIFF文件页数触发TypeError: int()参数类型错误

问题背景 #

我需要统计TIFF格式图片的页数，写了如下代码：

from pathlib import Path
from PIL import Image
import os

def count_pages(img):
    i = 0                                                                           
    while True:
        try:   
            img.seek(i)
        except EOFError:
            break       
        i += 1          
    return i

BASE_DIR = Path.cwd()
IDs_DIR = BASE_DIR / 'FLDR'
sPath = os.path.join(IDs_DIR, 'ggg.tiff')    
im = Image.open(sPath)
print(count_pages(im))

但部分TIFF文件运行时触发错误，报错信息如下：

site-packages\PIL\TiffImagePlugin.py:845: UserWarning: Corrupt EXIF data.  Expecting to read 2 bytes but only got 0.
  warnings.warn(str(msg))
Traceback (most recent call last):
  File "Demo.py", line 19, in <module>
    print(count_pages(im))
  File "Demo.py", line 9, in count_pages
    img.seek(i)
  File "C:\Users\Future\AppData\Local\Programs\Python\Python38\lib\site-packages\PIL\TiffImagePlugin.py", line 1101, in seek
    self._seek(frame)
  File "C:\Users\Future\AppData\Local\Programs\Python\Python38\lib\site-packages\PIL\TiffImagePlugin.py", line 1142, in _seek
    self._setup()
  File "C:\Users\Future\AppData\Local\Programs\Python\Python38\lib\site-packages\PIL\TiffImagePlugin.py", line 1333, in _setup
    xsize = int(self.tag_v2.get(IMAGEWIDTH))
TypeError: int() argument must be a string, a bytes-like object or a number, not 'NoneType'

解决办法 #

方法1：修改现有代码，捕获损坏帧异常 #

报错根源是损坏TIFF帧的IMAGEWIDTH标签值为None，导致int()转换失败。可以在count_pages函数中额外捕获TypeError，跳过损坏帧继续统计：

from pathlib import Path
from PIL import Image
import os

def count_pages(img):
    i = 0                                                                           
    while True:
        try:   
            img.seek(i)
            img.load()  # 强制加载帧数据，确保检测到损坏
        except EOFError:
            break
        except TypeError:
            # 遇到损坏帧，跳过并继续统计
            i += 1
            continue       
        i += 1          
    return i

BASE_DIR = Path.cwd()
IDs_DIR = BASE_DIR / 'FLDR'
sPath = os.path.join(IDs_DIR, 'ggg.tiff')    
im = Image.open(sPath)
print(count_pages(im))

方法2：换用tifffile库（兼容性更好） #

如果PIL的处理方式仍有问题，可以用tifffile库——它直接解析TIFF文件结构，不需要加载每帧数据，对损坏文件的兼容性更强。

首先安装库：

pip install tifffile

然后替换代码：

from pathlib import Path
import tifffile

BASE_DIR = Path.cwd()
IDs_DIR = BASE_DIR / 'FLDR'
sPath = IDs_DIR / 'ggg.tiff'    

with tifffile.TiffFile(sPath) as tif:
    print(len(tif.pages))

可选：关闭EXIF警告 #

如果不想看到EXIF损坏的警告信息，可以在代码开头添加：

import warnings
warnings.filterwarnings("ignore", category=UserWarning, module="PIL")

内容的提问来源于stack exchange，提问作者YasserKhalil