NAS

File Format
Name	NAS
Ontology	Electronic File Formats Graphics NAS
Extension(s)	.nas

A .NAS file is a compressed paletted image archive format. The format appears to be proprietary and specific to the Bunny Pro. Das2 visual novel software for Windows.

Specification

• This format has the signature 4E 41 00 00
• Payload-size (int)
• A fixed-size palette of 256 entries totalling 768 bytes. Each entry is a 3-byte tuple for the red, blue and green component. (Most images do not use all 256 entries but the palette is always 768 bytes)
• A series of chunks, either starting with the bytes AD or NB. Most images only have a single NB chunk.

NB chunk

The **NB** chunk contains image data and has the following format:

• Signature (ND)
• Image width (short)
• Image height (short)
• Unknown 1 (short) — usually 0 or 1
• Unknown 2 (short) — always 0
• Unknown 3 (short) — always 1
• Length of data (int)
• Image data

The image data is compressed and the method is unknown.

AD chunk

The format of this chunk is unknown:

• Signature (AD)
• Data (362 bytes)