Noise problem with iTunes optimization

I noticed severe image noise after I transferred my 320×480 photos to my iPhone. This is probably to do with the so called “optimization” done by iTunes.

Below is my original image:

Original Image

Original Image

Below is the “processed” image: (How did I get it? Select the image in iPhone and send email.)

Processed Image

Processed Image

Notice the added noise and slightly increased saturation. I tried to google to find out a way to disable the processing. No luck.

I tried to run process monitor on iTunes and found out the optimization is done by iTunesPhotoProcessor.exe. The processed image was saved into a .ithmb file. After a couple of hours, I couldn’t figure out a way to prevent the optimization.

Here is another attempt: Below is a comparison of the two JPEG header information:
ExifTool Version Number : 8.00
File Name : original.jpg
Directory : .
File Size : 41 kB
File Modification Date/Time : 2010:03:09 23:16:14+08:00
File Type : JPEG
MIME Type : image/jpeg
JFIF Version : 1.02
Resolution Unit : None
X Resolution : 100
Y Resolution : 100
Quality : 80%
DCT Encode Version : 100
APP14 Flags 0 : [14], Encoded with Blend=1 downsampling
APP14 Flags 1 : (none)
Color Transform : YCbCr
Image Width : 320
Image Height : 480
Encoding Process : Baseline DCT, Huffman coding
Bits Per Sample : 8
Color Components : 3
Y Cb Cr Sub Sampling : YCbCr4:4:4 (1 1)
Image Size : 320x480

ExifTool Version Number : 8.00
File Name : processed.jpg
Directory : .
File Size : 55 kB
File Modification Date/Time : 2010:03:09 08:25:10+08:00
File Type : JPEG
MIME Type : image/jpeg
JFIF Version : 1.01
Resolution Unit : None
X Resolution : 1
Y Resolution : 1
Image Width : 320
Image Height : 480
Encoding Process : Baseline DCT, Huffman coding
Bits Per Sample : 8
Color Components : 3
Y Cb Cr Sub Sampling : YCbCr4:2:0 (2 2)
Image Size : 320x480

The most suspicious differences are X&Y Resolution and YCbCr. Could any of these be the culprit? For example, I can generate an image with the same parameter as the processed image and hope iTunes will skip the processing. I haven’t tried this method yet…

Advertisements

2 Responses to “Noise problem with iTunes optimization”

  1. Qifei Says:

    Can you write a dummy iTunesPhotoProcessor.exe doing nothing but renaming the file?

    • wuyongzheng Says:

      Good idea. But I haven’t fully understand how iTunes and iTunesPhotoProcessor work together. There are some weird communication between them. Maybe a simple dummy program won’t work.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


%d bloggers like this: