Model reference · open weights

Open-Sora

Video hpcai-tech Text→video 1 build Open weights 4k dl/mo

Open-Sora is an open-weight video model from hpcai-tech. Open-Sora-v2 (BF16) weighs 48.4 GB; the smallest configuration that runs it is RTX 5090 32 GB.

  • Open-Sora is an open-source text-to-video model developed by hpcai-tech and published as hpcai-tech/Open-Sora-v2.
  • The 11B parameter model supports both text-to-video and image-to-video generation at 256px and 768px resolutions.
  • It is released under the Apache-2.0 license.

Summary of the hpcai-tech/Open-Sora-v2 model card, 2026-10-01

What it is

Released byhpcai-tech
Released2025-03-04
VRAM48.4 GB for the weights

What it runs on

Memory and cards for Open-Sora-v2 (BF16)

48.4 GBweights, file size
23.8 GBbiggest part
537 MBruntime overhead
CardWeightsMemory
RTX 3060 12 GB … RTX 4090 24 GBdoes not fit
RTX 5090 32 GBfits (encoders offloaded)31.0 GB
L40S 48 GBfits (encoders offloaded)44.0 GB
A100 80 GBfits78.2 GB
H100 80 GBfits78.1 GB
RTX PRO 6000 Blackwell 96 GBfits93.8 GB
DGX Spark (GB10) 128 GB unifiedfits107 GB
H200 141 GBfits138 GB
B200 180 GBfits176 GB

From the model card

What hpcai-tech says about Open-Sora

Read the model card

Open-Sora: Democratizing Efficient Video Production for All

We design and implement Open-Sora, an initiative dedicated to efficiently producing high-quality video. We hope to make the model, tools and all details accessible to all. By embracing open-source principles, Open-Sora not only democratizes access to advanced video generation techniques, but also offers a streamlined and user-friendly platform that simplifies the complexities of video generation. With Open-Sora, our goal is to foster innovation, creativity, and inclusivity within the field of content creation.

Paper

Github: https://github.com/hpcaitech/Open-Sora

🔆 Reports

📍 Since Open-Sora is under active development, we remain different branchs for different versions. The latest version is main. Old versions include: v1.0, v1.1, v1.2, v1.3.

Quickstart

Installation

# create a virtual env and activate (conda as an example)
conda create -n opensora python=3.10
conda activate opensora

# download the repo
git clone https://github.com/hpcaitech/Open-Sora
cd Open-Sora

# Ensure torch >= 2.4.0
pip install -v . # for development mode, `pip install -v -e .`
pip install xformers==0.0.27.post2 --index-url https://download.pytorch.org/whl/cu121 # install xformers according to your cuda version
pip install flash-attn --no-build-isolation

Optionally, you can install flash attention 3 for faster speed.

git clone https://github.com/Dao-AILab/flash-attention # 4f0640d5
cd flash-attention/hopper
python setup.py install

Model Download

Our 11B model supports 256px and 768px resolution. Both T2V and I2V are supported by one model. 🤗 Huggingface 🤖 ModelScope.

Download from huggingface:

pip install "huggingface_hub[cli]"
huggingface-cli download hpcai-tech/Open-Sora-v2 --local-dir ./ckpts

Download from ModelScope:

pip install modelscope
modelscope download hpcai-tech/Open-Sora-v2 --local_dir ./ckpts

Text-to-Video Generation

Our model is optimized for image-to-video generation, but it can also be used for text-to-video generation. To generate high quality videos, with the help of flux text-to-image model, we build a text-to-image-to-video pipeline. For 256x256 resolution:

# Generate one given prompt
torchrun --nproc_per_node 1 --standalone scripts/diffusion/inference.py configs/diffusion/inference/t2i2v_256px.py --save-dir samples --prompt "raining, sea"

# Generation with csv
torchrun --nproc_per_node 1 --standalone scripts/diffusion/inference.py configs/diffusion/inference/t2i2v_256px.py --save-dir samples --dataset.data-path assets/texts/example.csv

For 768x768 resolution:

# One GPU
torchrun --nproc_per_node 1 --standalone scripts/diffusion/inference.py configs/diffusion/inference/t2i2v_768px.py --save-dir samples --prompt "raining, sea"

# Multi-GPU with colossalai sp
torchrun --nproc_per_node 8 --standalone scripts/diffusion/inference.py configs/diffusion/inference/t2i2v_768px.py --save-dir samples --prompt "raining, sea"

You can adjust the generation aspect ratio by --aspect_ratio and the generation length by --num_frames. Candidate values for aspect_ratio includes 16:9, 9:16, 1:1, 2.39:1. Candidate values for num_frames should be 4k+1 and less than 129.

You can also run direct text-to-video by:

# One GPU for 256px
torchrun --nproc_per_node 1 --standalone scripts/diffusion/inference.py configs/diffusion/inference/256px.py --prompt "raining, sea"
# Multi-GPU for 768px
torchrun --nproc_per_node 8 --standalone scripts/diffusion/inference.py configs/diffusion/inference/768px.py --prompt "raining, sea"

Image-to-Video Generation

Given a prompt and a reference image, you can generate a video with the following command:

# 256px
torchrun --nproc_per_node 1 --standalone scripts/diffusion/inference.py configs/diffusion/inference/256px.py --cond_type i2v_head --prompt "A plump pig wallows in a muddy pond on a rustic farm, its pink snout poking out as it snorts contentedly. The camera captures the pig's playful splashes, sending ripples through the water under the midday sun. Wooden fences and a red barn stand in the background, framed by rolling green hills. The pig's muddy coat glistens in the sunlight, showcasing the simple pleasures of its carefree life." --ref assets/texts/i2v.png

# 256px with csv
torchrun --nproc_per_node 1 --standalone scripts/diffusion/inference.py configs/diffusion/inference/256px.py --cond_type i2v_head --dataset.data-path assets/texts/i2v.csv

# Multi-GPU 768px
torchrun --nproc_per_node 8 --standalone scripts/diffusion/inference.py configs/diffusion/inference/768px.py --cond_type i2v_head --d

Quoted from the model card on Hugging Face. The full card is behind the Hugging Face link above.

How it works

How video models work

Prompt / imagestart pointTemporal diffusionframes over timeVideoMP4 clipA video model generates a sequence of coherent frames from your prompt or a starting image.

Running it yourself

Run it on a rented GPU

Rent a machine by the hour. ComfyUI is installed on it. Open ComfyUI through the tunnel and load the workflow from the model's card on Hugging Face; choose this model's file in its loader.

# on your rented machine (the ssh line is on its page in the console)
# get REPO FILE FOLDER: one file into /workspace/models/FOLDER, where ComfyUI loads it from
get() { hf download "$1" "$2" --local-dir /workspace/hf-files && mkdir -p "/workspace/models/$3" && mv "/workspace/hf-files/$2" "/workspace/models/$3/$4"; }

# the model (24.5 GB)
get hpcai-tech/Open-Sora-v2 Open_Sora_v2.safetensors diffusion_models
get hpcai-tech/Open-Sora-v2 openai/clip-vit-large-patch14/model.safetensors text_encoders
get hpcai-tech/Open-Sora-v2 flux1-dev-ae.safetensors vae
get hpcai-tech/Open-Sora-v2 hunyuan_vae.safetensors vae

start-comfyui
Renting a GPU: connect, tunnels, ComfyUI
# on your computer, in a second terminal: ComfyUI in your browser at http://localhost:8188
# HOST and PORT are your machine's, from its page in the console
ssh -L 8188:localhost:8188 dev@HOST -p PORT
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