for the last 6 years, i have been trying to crack open some files. in early 2018 i was given a bunch of video files with the .AVS file extension, from a cancelled FMV game from the early 90s named Duelin' Firemen.

at this time, i was deep in a project to document and interview as many people from the company (RUNANDGUN! Inc.) as i possibly could. the files were given to me with the expectation that i could convert them, and allow them to be seen again.

this didn't happen. atleast, not then.

as it turns out, the AVS video format is almost a complete mystery. back in 2018 my "hacker skills" were severely lacking, and i only had a few leads. at the time i was told that they edited Duelin' Firemen on a D/Vision Pro PC editing system, operating on the footage they had originally shot on 16mm film and then transferred to Beta tapes. so i started there. i didn't find much... only a few advertisements from the era showing the system, and a small reference to something called the "ActionMedia II", which was some kind of multimedia accelerator card created by Intel in the late 80s as a gambit in the PC multimedia market. it failed, which is why you've never heard of it.

the ActionMedia II card used AVS as one of its primary file formats. it's not really close to the AVI video format, though apparently there was some interop between them. in the early 90s Intel offered a tool for Windows 3.1 that could convert your AVS files into AVI, but it was seemingly very limited (it didn't work on my files, for example).

so after a bunch of bumbling around doing google searches and finding almost nothing, i gave up. later in 2019 i tried again and made no progress. but, as of this week in 2024, i have finally made some real progress in decoding them.

this random page was a huge help: ActionMedia II from "Ardent Tool of Capitalism". it provided drivers for Windows 3.1, the aforementioned converter tool (which didn't work) and a load of documentation on the usage of the card itself. back in 2018 i never discovered this wildly useful webpage: Intel DVI File Format Summary at fileformat.info - though there wasn't much i could've done with it at the time. i was not a programmer then. the page details the entire structure of the AVS file format (apparently the proper name was Intel DVI) along with some scant details on decoding them.

so for the past few days i've been working through the files with ImHex, writing a pattern file that describes AVS based on this spec. it's not all smooth sailing, though. the spec is either older or newer than the files i have and some of the structures dont exactly match. i've had to ditch or widen a few of the fields to get everything to match up. but it's definitely the correct format.

the page says that the spec came from the book "Encyclopedia of Graphics File Formats, 2nd Edition". initially i thought i wouldn't be able to get a copy of this book, but while writing this post i found out that the contents of the book are available from O'Reiley's git resources subdomain for some reason.

and finally, we have found genuine Intel DVI file format spec.

at time of writing i have not fully read through this document, but i am planning to try and absorb as much of it as i can and write a converter for the AVS files i got in 2018.

so, see you then. i will create a new post when i have the files cracked. happy hacking!