Recently I’ve posted a short review of DPCM-based video codecs where Indeo 2 and 3 were mentioned, but what about Indeo 1?
Previously I believed that it’s their raw format aka IF09 (YVU 4:1:0 with 7 bits per component) but recently I’ve discovered a codec called Indeo YVU9 Compressed, which kinda fills the gap between raw video and comparatively complex Indeo 2 (which employs not merely delta coding but also vector quantisation and zero-run coding).
This format codes intra-only frames plane per plane with simple delta prediction and fixed Huffman codes for small deltas plus escape value (which means full 8-bit code value should be read). In other words, a perfect initial DPCM-based codec which can be improved in different ways.
I cannot tell if this codec really deserves to be called Indeo 1 (relegating IF09 to Indeo 0) or it’s some simplification of Indeo 2 that came later. As you know, Indeo codecs come from DVI (no, not the display interfaces) and they had different names. From what I can tell there were three video codec families there: RTV (real-time video), PLV (production-level video, not as fast) and PIC (whatever that is). RTV2 is now known as Indeo 2 but it’s hard to tell which one was Indeo 1 (if there was any) or YVU9C. What’s worse is that there’s next to no software specifications for DVI, you were supposed to use special cards with Intel chipset to encode and decode it.
In either case, it’s yet another codec reverse engineered.