• A Hex Editing tool
  
  • Recommended: https://mh-nexus.de/en/hxd

• A program to open/view .dds files
  
  • Recommended: https://www.gimp.org

• First, locate the game in question and make a copy of the .cat file you wish to extract from.

• Next, open your Hex Editing tool of choice and open the .cat file with the tool to view the byes.
  
  • For this example, I will be using title_ui.cat originally located in "\Neptunia U\ui"

• In the Hex Editing tool, locate "DDS" within the Decoded Text.
  
  • Note: Must be similar to the example below. "DXT#" should be visible and after the format (which should be "DDS" for this case), which indicates the texture compression used for images.

• Select all byes just before "DDS" in the decoded text. And delete it/remove it from the file.
  
  • Note: "DDS" in hex bytes should always be "44 44 53" anything before that must be taken out.

• Save the file in the Hex Editor tool, then open the .cat file using the DDS viewing tool.
  
  • In this example, I'm using GIMP. And changing the file's extension, surprisingly, isn't necessary.

• Now that the image is opened in the DDS viewing tool, it can then be exported to the format of your choice.

Depending on the file in question, there can be multiple DDS headers in a single .cat file. When opening it in the DDS viewing tool it will only display a single image, which is the first DDS listed in the Decoded text.

In such a case, you'll need to locate the next "DDS" instance, and follow the same procedure with selecting all bytes before the desired entry, and removing it from the file.

Once done, when opening the same .cat file in the DDS viewing tool, the next image in that package should be able to load.



Following the example used in this guide, there are multiple DDS files, as discovered by the DDS headers in the "title_ui.cat". Removing the first instance, will allow the second DDS file in that packet to load, which is the clean title screen used in the game.