JPEGsnoop | JPEGsnoop : JPEG decoder and detailed analysis | Computer Vision library

by ImpulseAdventure C++ Version: v1.8.0 License: GPL-2.0

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kandi X-RAY | JPEGsnoop Summary

JPEGsnoop is a C++ library typically used in Artificial Intelligence, Computer Vision applications. JPEGsnoop has no bugs, it has no vulnerabilities, it has a Strong Copyleft License and it has low support. You can download it from GitHub.

JPEGsnoop is a detailed JPEG image decoder and analysis tool. It reports all image metadata and can even help identify if an image has been edited. Official repository for JPEGsnoop: JPEGsnoop @ GitHub.

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JPEGsnoop has a low active ecosystem.

It has 423 star(s) with 79 fork(s). There are 31 watchers for this library.

It had no major release in the last 12 months.

There are 45 open issues and 6 have been closed. On average issues are closed in 125 days. There are 1 open pull requests and 0 closed requests.

It has a neutral sentiment in the developer community.

The latest version of JPEGsnoop is v1.8.0

Quality

JPEGsnoop has 0 bugs and 0 code smells.

Security

JPEGsnoop has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.

JPEGsnoop code analysis shows 0 unresolved vulnerabilities.

There are 0 security hotspots that need review.

License

JPEGsnoop is licensed under the GPL-2.0 License. This license is Strong Copyleft.

Strong Copyleft licenses enforce sharing, and you can use them when creating open source projects.

Reuse

JPEGsnoop releases are available to install and integrate.

Installation instructions are available. Examples and code snippets are not available.

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JPEGsnoop Key Features

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JPEGsnoop Examples and Code Snippets

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Community Discussions

Trending Discussions on JPEGsnoop

is a jpeg with a bogus huffman table recoverable?

QUESTION

is a jpeg with a bogus huffman table recoverable?

Asked 2018-Oct-25 at 16:05

I have a JPEG that is un-openable in any program:

Opening in Ubuntu Image Viewer yields:

Passing the photo through convert yields similar results:

...

ANSWER

Answered 2018-Oct-25 at 16:05

The approach used to get this back was more luck than judgement. I think I can explain, though be aware it involves a hex editor...

The Wikipedia page for the syntax of a JPEG file explains that it is made up of a series of segments each started by a two byte marker - 0xFF and another byte to indicate the type of segment.

The hope was that it was just the Huffman table segment of the file that was wrong - as suggested by the error message. Without needing to understand what a Huffman table is, it was enough to see that the same section on Wikipedia explains it is a 0xFF 0xC4 marker for a Huffman table segment.

Further down the page, it mentions:

The JPEG standard provides general-purpose Huffman tables; encoders may also choose to generate Huffman tables...

Opening up a few other JPEG files found what looks like a standard set of 4 consecutive Huffman table segments - each starting with that 0xFF 0xC4 marker. The sample corrupt.jpg however just had one Huffman table - from position 0x00c8 to 0x02bc below.

(Both contain that &'()*56789:CDEFGHIJSTUVWXYZcdefghijstuvwxyz sequence you mentioned in their Huffman tables. In the corrupt file it appears twice in that single Huffman table, in the 'more conventional' JPEGs it appears in the second and fourth Huffman tables.)

From there, the fixed image is a copy and paste of the standard 4 Huffman tables, in place of that range of bytes in corrupt.jpg - now from 0x00c8 to 0x0278 in the fixed file.

Because the JPEG format is based around scanning for segments between those 0xff markers, you can just swap out the Huffman segments - there are no other pointers in the file to worry about. As you said, the rest of the file looked like a plausible JPEG.

Summary of the steps taken:

Hex search the corrupt.jpg for FF C4 and note the offset
Hex search for the next FF. If it's another FF C4 (so a second Huffman table) keep going
Delete the content from the first FF C4 (included) up to but not including the next FF
Instead replace it with the 'standard 4 Huffman tables'. These are the bytes in the last sample below, or can be copied from 0x00c8 to 0x0278 in the fixed file