Filesize decreases abnormally

[mkolici]

Hi,
I have noticed a strange behavior of XNConvert:

I perform the following actions:

Rotate +180 degree
Rotate -180 degree.

It is supposed that the result image be the same as original. But I see that the size of the result photo is decreased. In my example from 1,537,133 bytes into 339,688 .
Please advise if this is a bug or it was intended so. I observe carefully the photo and I do not see any decrease in the quality. I have attached both files if you need to analyze further.

Thank you

[cday]

I have noticed a strange behavior of XNConvert:

I perform the following actions:

Rotate +180 degree
Rotate -180 degree.

It is supposed that the result image be the same as original. But I see that the size of the result photo is decreased. In my example from 1,537,133 bytes into 339,688 ... I do not see any decrease in the quality.

The explanation is that the JPG compression level in the original image of 98% has been changed to 80% in the saved image, and as you say there is no obvious change of quality...

You can set the file format and compression level on the XnConvert 'Output' tab:

Note: Your post will be moved to the XnConvert section of the forum.

[mkolici]

Hi,
I did not know this trick. I configured the output format "same as source", but indeed it does not output the quality level the same as source, but as it is configured in default settings of JPEG. Now I understand it.

Thank you
Mikel

[XnTriq]

The “classic” (non-multi-platform) edition of XnView allows you to rotate JPEG images in batch mode without re-encoding them:

• Tools » Batch Processing... » Transformations » Image » JPEG lossless rotation

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