shell - 使用 exiv2 或 imagemagick 从标准输入中删除 EXIF 数据并输出到标准输出

Question

如何将图像通过管道传输到 exiv2 或 imagemagick，剥离 EXIF 标签，然后将其传输到标准输出以进行更多操作？

我希望有类似的东西：

exiv2 rm - - | md5sum

这将输出通过标准输入提供的图像并计算其 md5sum。

或者，有没有更快的方法来做到这一点？

Answer 1

Using exiv2

I was not able to find a way to get exiv2 to output to stdout -- it only wants to overwrite the existing file. You could use a small bash script to make a temporary file and get the md5 hash of that.

image.sh:

#!/bin/bash
cat <&0 > tmp.jpg  # Take input on stdin and dump it to temp file.
exiv2 rm tmp.jpg   # Remove EXIF tags in place.
md5sum tmp.jpg     # md5 hash of stripped file.
rm tmp.jpg         # Remove temp file.

You would use it like this:

cat image.jpg | image.sh

Using ImageMagick

You can do this using ImageMagick instead by using the convert command:

cat image.jpg | convert -strip - - | md5sum

Caveat:

I found that stripping an image of EXIF tags using convert resulted in a smaller file-size than using exiv2. I don't know why this is and what exactly is done differently by these two commands.

From man exiv2:

rm        Delete image metadata from the files.

From man convert:

-strip        strip image of all profiles and comments

Using exiftool

ExifTool by Phil Harvey

You could use exiftool (I got the idea from https://stackoverflow.com/a/2654314/3565972):

cat image.jpg | exiftool -all= - -out - | md5sum

This too, for some reason, produces a slightly different image size from the other two.

Conclusion

Needless to say, all three methods (exiv2, convert, exiftool) produce outputs with different md5 hashes. Not sure why this is. But perhaps if you pick a method and stick to it, it will be consistent enough for your needs.

Answer 2

我用NEF文件测试过。似乎只有 exiv2 rm 效果最好。exiftool并且convert无法从 .nef 文件中删除所有元数据。

exiv2 rm请注意，大多数图像查看器无法再显示的输出文件。但是我只需要在更新 .NEF 文件的任何元数据后保持 MD5 哈希值不变。它对我来说很完美。