A few months ago we set ourselves a deceptively simple goal: produce coherent, high-quality video longer than 15 seconds, on a single GPU, in well under a minute of wall-clock time. Today's video diffusion models like Wan2.2 are good at 3–5 second clips. Stretching that to 10s, 30s, or a minute is where things get interesting. This post documents the route we actually took. We surveyed six approaches that show up in recent papers and tech reports — TTT, LoL, Self Forcing, Self Forcing++, Infinite Talk, and Helios — measured the trade-offs, and ultimately landed on SVI (Stable Video Infinity), wired up next to TurboWan in our DiffSynth Engine. We will go over each of those routes, then how SVI works, then the production numbers. Why long video is hard Three things break when you push past about five seconds. The VRAM wall Wan2.2 uses Full Attention with O(n²) cost in the number of latent tokens.…