H3 inference engine's performance, compatibility, and user experience on Apple Silicon (M4 Max, M5 Max), specifically for high-resolution, long-duration video generation, and memory management. Also, documentation and GUI status.

Hello,

I am very interested in using h3.c on my Mac with an M4 Max chip and 64GB of unified memory. Before diving in, I have three practical questions that I hope you or the community could help clarify.

1. **M4 Max (64GB) compatibility and performance**
The README mentions that current optimizations are incremental for M3 Max and M5 Max. Has there been any testing on the M4 Max? Are there any known performance figures (e.g., time per step for a 512×512, 22‑frame run) or special environment variables (like `H3_NAX` or Metal flags) that might improve performance on this chip? Also, does the 64GB memory size handle the full model comfortably, especially when using the `--show` preview (which adds ~10 GiB extra memory)?

2. **Estimated generation time for a 15‑second 720p video**
The benchmarks in the README show impressive speeds for short 512×512 clips. However, I would like to generate longer, higher‑resolution videos – for example, 15 seconds at 720p (roughly 362 frames at 24 fps, e.g., 1344×768 or 1280×720). Could you provide an approximate generation time on a typical M5 Max or M4 Max, assuming default settings (e.g., 20 steps, 45 layers, reuse 2)? If no direct numbers exist, any rough estimate or scaling rule (e.g., time proportional to frames × pixels) would be very helpful. I am also open to using internal render resolution or token reduction to speed things up, but I would like to know if the quality‑time trade‑off is acceptable for such long videos.

3. **Grap...