Microsoft Comic Chat

Latest revision as of 18:00, 18 July 2026

Microsoft Comic Chat was an IRC chat client that tried to represent a chat in the style of a comic book, with participants as graphical characters and their messages displayed in speech bubbles. It could use custom background and character graphics, given the extensions ".bgb" and ".avb", respectively. Characters and backgrounds were initially greyscale, but version 2.1 allowed the inclusion of color.^[1] It was conceived, and its development led, by David Kurlander.^[2] Comic Chat was released 1996 and last updated in 1999.^[3] The source code was released in 2026.

[edit] Format details

(Information here is unofficial.)

A file consists of a 6-byte header, followed by a sequence of tagged "chunks", followed by a data section sandwiched between tags 06 00 and 07 00.

There seem to be two major versions of the format:

• The format used by Comic Chat v1.0-2.1. The format version number is 1, but we'll call it "v2.1" format.
• The format used by Comic Chat v2.5. The format version number is 2, but we'll call it "v2.5" format.

The format version number is at offset 4-5.

It's not clear what the field at offset 2-3 is for. It could be something like a minor version, or file type, or to distinguish official and custom characters.

V2.1 files contain images in BMP format, though not necessarily interpreted in the standard way.

In v2.5 files, the image data is compressed with zlib.

[edit] Identification

AVB v2.1: Files begin with (hex) byte pattern 81 00 ?? 00 01 00, where the "??" byte is 01 or 02. The next two bytes (offset 6) might always be 01 00, though this is not a signature -- it's a tag for the "Name" chunk that (always?) appears first in the file.

AVB v2.5: Files begin with 81 81 ?? 00 02 00, where the "??" byte is 01 or 02.

BGB v2.5: Files begin with 81 81 03 00 02 00. The byte at offset 7 (the high byte of the first tag ID) might always be 01.

All files normally end with bytes 07 00.

[edit] Software

• Microsoft Comic Chat itself
  • Source code
• AVBuster, C++ program to extract images
  • Annotated source
• Page with creation programs
• Deark

[edit] Sample Files

Various:

• dexvert samples — other/microsoftChatCharacter

AVB v2.1:

• Most files at [1], "Add-On Characters" section
• MSCHAT2.CAB → *.avb

AVB v2.5:

• Directory of pages with characters (most files)
• [2] → Win98/Msie540/mschat25.cab → *.avb

BGB:

• Directory of pages with backgrounds
• [3] → Win98/Msie540/mschat25.cab → *.bgb

[edit] Links

• David Kurlander's Comic Chat Resources
  • Comic Chat - How to Get Started
• Mermaid Elizabeth's Microsoft Comic Chat Resources Link Page & Support (Somehow still being updated in 2020)
  • Phoenix Comic Chat Help
• Microsoft Comic Chat How2
• Sniffles' Comic Chat Place
• Wikipedia:Microsoft Comic Chat

[edit] References

1. ↑ https://www.mermeliz.com/cchars.htm#mschat21
2. ↑ https://kurlander.net/DJ/Projects/ComicChat/resources.html
3. ↑ Wikipedia:Microsoft Comic Chat