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🚀 SANA-Video 2.0 is here! A full-stack optimized video model designed for efficiency — while still delivering high quality. We combine a hybrid architecture closely related to the recent Kimi K3 design, adopt Self-Flow from FLUX 3, and further accelerate it with our own Sol-Engine. Key technical ingredients: 🧠...

25,721 views • 3 months ago •via X (Twitter)

24 Comments

Enze Xie's profile picture
Enze Xie3 months ago

1/3 Motivation: Why hybrid attention? 🤔 Full 3D softmax attention captures rich spatial–temporal interactions, but its O(N²) cost grows rapidly with video resolution and duration. Pure linear attention scales as O(N), but compressing token interactions into a fixed-size state limits rank and expressiveness. SANA-Video 2.0 keeps most layers linear, then inserts sparse softmax anchors to recover the interactions that pure linear attention misses—combining long-sequence efficiency with softmax-level quality.

Enze Xie's profile picture
Enze Xie3 months ago

2/3 🧬 From Frontier LLMs to Video Generation SANA-Video 2.0 follows the same high-level direction as Kimi K3: a mostly-linear hybrid-attention backbone paired with cross-layer Block AttnRes. Each 4-layer cycle contains: • 3 gated linear-attention layers for efficient global mixing • 1 gated-softmax anchor for periodic full-rank refresh • Attention Residual for recovery of low-rank representations in linear attention A from-scratch ratio sweep identifies this 75% linear / 25% softmax design as the practical quality–efficiency Pareto knee. The softmax anchors restore richer token interactions, while Block AttnRes carries these refreshed features into deeper linear layers—improving their effective rank by 11.7%. We adapt this frontier LLM recipe to bidirectional video diffusion and massive spatial–temporal token sequences. The backbone is trained from scratch, without post-hoc linearization or a pretrained image-generation prior.

Enze Xie's profile picture
Enze Xie3 months ago

3/3 ⚙️ Full-Stack Training & Deployment We also disclose the complete training recipe: • Pre-training → continual training → 720p SFT • Raw-video processing, cleaning, filtering, and multi-axis scoring • Flow matching with content- and token-aware timestep sampling • Self-Flow feature distillation during pre-training and continual training • DPO and online ReFL for preference alignment For deployment, the convolution-free SwiGLU backbone maps cleanly to fused kernels. Sol-Engine further combines kernel fusion, caching, and sparse attention—bringing 720p/5s generation to 13.06s on a single H100. Efficient architecture, efficient training, and efficient inference—optimized end to end.

Valeriy (WaveCut) Selitskiy's profile picture
Valeriy (WaveCut) Selitskiy3 months ago

Looks pretty good! Do you plan to share the model weights?

Enze Xie's profile picture
Enze Xie3 months ago

yes, will open sourse asap

Valeriy (WaveCut) Selitskiy's profile picture
Valeriy (WaveCut) Selitskiy3 months ago

Awesome!

Andrei Filatov's profile picture
Andrei Filatov3 months ago

so fast

Memory Paper's profile picture
Memory Paper3 months ago

Exciting updates, especially the Self-Flow integration sounds promising!

Aaliya's profile picture
Aaliya3 months ago

Fast and high quality is a great combination.

Aina Ai | Tools & Updates's profile picture
Aina Ai | Tools & Updates3 months ago

Efficiency beast 720p video on a single H100 in 13s and 120x faster than Wan SANA Video 2.0 just made high quality video generation actually practical

AI Mastery Guide's profile picture
AI Mastery Guide3 months ago

720p in 13 seconds on one H100 is genuinely impressive.

Martin Ronfort's profile picture
Martin Ronfort3 months ago

Efficiency-first architecture is the move now. Hybrid design, sparse activation, every layer optimized—Kimi K3 proved it works. Curious what the token-per-dollar math looks like with your accelerations.

Obama's profile picture
Obama3 months ago

This is the real democratization of video AI: 720p/5s on a single H100 at 13 seconds isn't just an optimization—it's the threshold where research labs and indie devs finally get to play in the same sandbox as the giants. 🚀5

ZenithAi's profile picture
ZenithAi3 months ago

Impressive engineering work pushing efficient AI video generation forward

TechGeekDavid's profile picture
TechGeekDavid3 months ago

Very interesting work from NVlabs. Hybrid linear-softmax is the right approach. Pure linear attention loses too much expressiveness at deeper layers.

Miles Penn's profile picture
Miles Penn3 months ago

Why choose the LTX VAE vs. others?

Enze Xie's profile picture
Enze Xie3 months ago

because ltx vae has high compression ratio and good reconstruction capabilities

InsightGenius's profile picture
InsightGenius1 month ago

solid. what'd break first when you pushed kimi past the demo?

Furkan Gözükara's profile picture
Furkan Gözükara3 months ago

Nice but seems like dataset and training duration are insufficient

下前勝郎's profile picture
下前勝郎3 months ago

open source coming soon?

IF's profile picture
IF3 months ago

The quality looks good but the slow motion bias is terrible :(

Aggroed Lighthacker- Peace, Prosperity, & Freedom's profile picture
Aggroed Lighthacker- Peace, Prosperity, & Freedom3 months ago

open source?

Enze Xie's profile picture
Enze Xie3 months ago

sure thing

InsightGenius's profile picture
InsightGenius1 month ago

honest take: if kimi only works on a clean demo tree I'm out. you run this on real work yet?

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Enze Xie

209,411 views • 1 month ago