All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 25 posts ]  Go to page Previous  1, 2
Author Message
 Post subject: Re: JPEG Repair Service
PostPosted: March 30th, 2016, 17:57 
Offline
User avatar

Joined: September 8th, 2009, 18:21
Posts: 9382
Location: Australia
I've been doing some experimenting with "progressive scan" JPEGs. These consist of several interlaced scans.

In some cases I can truncate the last 80% of the file without visibly affecting the image, at least to my eyes. The extent to which I can do this depends on the amount of detail in the image.

In the following example I truncate the last quarter of the test file:

Attachment:
test_Spildit_original_resized_progressive.jpg
test_Spildit_original_resized_progressive.jpg [ 234.54 KiB | Viewed 829 times ]

Attachment:
test_Spildit_original_resized_progressive_trunc_2C810.jpg
test_Spildit_original_resized_progressive_trunc_2C810.jpg [ 178.02 KiB | Viewed 829 times ]


In the next example the file is truncated by half:

Attachment:
CDC_progressive.JPG
CDC_progressive.JPG [ 96.61 KiB | Viewed 829 times ]

Attachment:
CDC_progressive_trunc_B970.JPG
CDC_progressive_trunc_B970.JPG [ 46.36 KiB | Viewed 829 times ]


Here the file is truncated to 20% of its size

Attachment:
JMicron_progressive.jpg
JMicron_progressive.jpg [ 251.2 KiB | Viewed 829 times ]

Attachment:
JMicron_progressive_trunc_BEE0.jpg
JMicron_progressive_trunc_BEE0.jpg [ 47.72 KiB | Viewed 829 times ]


The point at which successive scans begin and end looks like the following:

Code:
Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

0000BEA0  D6 13 FD 5D DE 2D 55 5F DA A7 F2 AF FF C4 00 4A
0000BEB0  11 00 02 01 02 04 02 05 08 06 07 07 03 03 05 00
0000BEC0  00 01 02 03 00 11 04 12 21 31 13 41 05 22 32 51
0000BED0  61 10 14 23 33 71 81 91 A1 20 42 52 62 B1 C1 15

_________________
A backup a day keeps DR away.


Top
 Profile  
 
 Post subject: Re: JPEG Repair Service
PostPosted: March 31st, 2016, 16:39 
Offline
User avatar

Joined: December 19th, 2006, 8:49
Posts: 7759
Location: Portugal
Very cool !

_________________
1Q9xrDTzTddUXeJAFRn37aqh1Yr6buDCdw - (Bitcoin Donations)
The HDD Oracle - Platform for OPEN research on Data Recovery.


Top
 Profile  
 
 Post subject: Re: JPEG Repair Service
PostPosted: April 17th, 2016, 17:32 
Offline

Joined: December 5th, 2011, 5:38
Posts: 1041
Location: Italy
We can start a new game here :)
Someone can upload a damaged pic here, then we try to repair it and upload output file, we will find out who is the best DR in pics repairing by comparing them
:lol: :lol: :lol:


Top
 Profile  
 
 Post subject: Re: JPEG Repair Service
PostPosted: February 13th, 2017, 15:24 
Offline
User avatar

Joined: September 8th, 2009, 18:21
Posts: 9382
Location: Australia
http://www.hddoracle.com/viewtopic.php?t=1943&p=11616#p11616

Quote:
JPEG Repair Shop allows you to repair corrupt JPEG files by manipulating the internal structure of the JPEG file. This makes it possible to repair corrupt files, which would be impossible to fix in a normal image editor.

http://anderspedersen.net/jpegrepair/

How does it work?

The image data of JPEG is divided into small rectangular areas called MCUs (Minimum Coded Unit) which are encoded together. Because of the way JPEG files are compressed an error in an MCU is likely to be propagated to the remaining image data, either displacing the image or changing the colors. JPEG Repair Shop allows you to delete and insert MCUs and to automatically fix color errors.

_________________
A backup a day keeps DR away.


Top
 Profile  
 
 Post subject: Re: JPEG Repair Service
PostPosted: February 13th, 2017, 15:32 
Offline
User avatar

Joined: December 19th, 2006, 8:49
Posts: 7759
Location: Portugal
fzabkar wrote:
http://www.hddoracle.com/viewtopic.php?t=1943&p=11616#p11616

Quote:
JPEG Repair Shop allows you to repair corrupt JPEG files by manipulating the internal structure of the JPEG file. This makes it possible to repair corrupt files, which would be impossible to fix in a normal image editor.

http://anderspedersen.net/jpegrepair/

How does it work?

The image data of JPEG is divided into small rectangular areas called MCUs (Minimum Coded Unit) which are encoded together. Because of the way JPEG files are compressed an error in an MCU is likely to be propagated to the remaining image data, either displacing the image or changing the colors. JPEG Repair Shop allows you to delete and insert MCUs and to automatically fix color errors.


As a matter of fact I've "discovered it" here :

http://forums.recoveryforce.com/viewtopic.php?f=4&t=208

Original post was from @lcoughey .

I just checked the http://anderspedersen.net/jpegrepair/ site, downloaded the software and figure that it could be a nice this to add to the software section of the Oracle as well :)

_________________
1Q9xrDTzTddUXeJAFRn37aqh1Yr6buDCdw - (Bitcoin Donations)
The HDD Oracle - Platform for OPEN research on Data Recovery.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 25 posts ]  Go to page Previous  1, 2

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 3 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group