Model reference · open weights
Sa2VA is an open-weight language model from ByteDance. AxForge deploys and operates it for you on dedicated EU-owned hardware — with the licence handled where one is required.
Available as managed deployment — configured and operated for you on dedicated EU hardware, quoted per deployment.
What it is
| Released by | ByteDance |
|---|---|
| Type | Language models |
| Task | Vision + text |
| Parameters (lead) | 8.3B |
| Runs with | transformers |
| Based on | OpenGVLab/InternVL2.5-8B |
| Released | 2025-01-07 |
| Popularity | 6k downloads / month |
| Licence | Open weights |
About
[📂 GitHub] [📜 Sa2VA paper] [🚀 Quick Start]
Sa2VA is an MLLM capable of question answering, visual prompt understanding, and dense object segmentation at both image and video levels. It achieves comparable performance to SOTA MLLMs Qwen2-VL and InternVL2.5 on question-answering benchmarks. Additionally, Sa2VA possesses the visual prompt understanding and dense object segmentation capabilities that SOTA MLLMs Qwen2-VL and InternVL2.5 lack. Sa2VA achieves SOTA performance on both image and video grounding and segmentation benchmarks.
We built the Sa2VA series based on Qwen2-VL and InternVL2/2.5. In the following table, we provide some Sa2VA models built on InternVL2.5. Other Sa2VA models will be open-sourced soon.
| Model Name | Base MLLM | Language Part | HF Link |
|---|---|---|---|
| Sa2VA-1B | InternVL2.5-1B | Qwen2.5-0.5B-Instruct | 🤗 link |
| Sa2VA-4B | InternVL2.5-4B | Qwen2.5-3B-Instruct | 🤗 link |
| Sa2VA-8B | InternVL2.5-8B | internlm2_5-7b-chat | 🤗 link |
| Sa2VA-26B | InternVL2.5-26B | internlm2_5-20b-chat | 🤗 link |
| Model Name | MME | MMBench | RefCOCO | RefCOCO+ | RefCOCOg | MeVIS (val_u) | DAVIS |
|---|---|---|---|---|---|---|---|
| Sa2VA-1B | 1504/434 | 71.9 | 79.6 | 73.6 | 77.7 | 53.4 | 69.5 |
| Sa2VA-4B | 1691/610 | 81.8 | 82.4 | 77.6 | 79.7 | 55.9 | 73.7 |
| Sa2VA-8B | 1690/610 | 84.4 | 82.6 | 78.0 | 80.3 | 58.9 | 75.9 |
| Sa2VA-26B | 1698/653 | 85.8 | 82.9 | 79.3 | 81.2 | 61.8 | 78.6 |
We provide an example code to run Sa2VA using transformers.
import torch
from transformers import AutoTokenizer, AutoModel
from PIL import Image
import numpy as np
import os
# load the model and tokenizer
path = "ByteDance/Sa2VA-8B"
model = AutoModel.from_pretrained(
path,
torch_dtype=torch.bfloat16,
low_cpu_mem_usage=True,
use_flash_attn=True,
trust_remote_code=True).eval().cuda()
tokenizer = AutoTokenizer.from_pretrained(path, trust_remote_code=True, use_fast=False)
# for image chat
image_path = "/PATH/TO/IMAGE"
text_prompts = "Please describe the image."
image = Image.open(image_path).convert('RGB')
input_dict = {
'image': image,
'text': text_prompts,
'past_text': '',
'mask_prompts': None,
'tokenizer': tokenizer,
}
return_dict = model.predict_forward(**input_dict)
answer = return_dict["prediction"] # the text format answer
# for image chat with segmentation output
image_path = "/PATH/TO/IMAGE"
text_prompts = "Could you please give me a brief description of the image? Please respond with interleaved segmentation masks for the corresponding parts of the answer."
image = Image.open(image_path).convert('RGB')
input_dict = {
'image': image,
'text': text_prompts,
'past_text': '',
'mask_prompts': None,
'tokenizer': tokenizer,
}
return_dict = model.predict_forward(**input_dict)
answer = return_dict["prediction"] # the text format answer
masks = return_dict['prediction_masks'] # segmentation masks, list(np.array(1, h, w), ...)
# for chat with visual prompt (mask format) input
mask_prompts = np.load('/PATH/TO/pred_masks.npy') # np.array(n_prompts, h, w)
image_path = "/PATH/TO/IMAGE"
text_prompts = "Can you provide me with a detailed description of the region in the picture marked by region1."
image = Image.open(image_path).convert('RGB')
input_dict = {
'image': image,
'text': text_prompts,
'past_text': '',
'mask_prompts': mask_prompts,
'tokenizer': tokenizer,
}
return_dict = model.predict_forward(**input_dict)
answer = return_dict["prediction"] # the text format answer
# for video chat
video_folder = "/PATH/TO/VIDEO_FOLDER"
images_paths = os.listdir(video_folder)
images_paths = [os.path.join(video_folder, image_path) for image_name in images_paths]
if len(images_paths) > 5: # uniformly sample 5 frames
step = (len(images_paths) - 1) // (5 - 1)
images_paths = [images_paths[0]] + images_paths[1:-1][::step][1:] + [images_paths[-1]]
text_prompts = "Please describe the video."
input_dict = {
'video': images_paths,
'text': text_prompts,
'past_text': '',
'mask_prompts': None,
'tokenizer': tokenizer,
}
return_dict = model.predict_forward(**input_dict)
answer = return_dict["prediction"] # the text format answer
# for video chat with segmentation mask output
video_folder = "/PATH/TO/VIDEO_FOLDER"
images_paths = os.listdir(video_folder)
images_paths = [os.path.join(video_folder, image_path) for image_name in images_paths]
text_prompts = "Please segment the person."
input_dict = {
'video': images_paths,
'text': text_prompts,
'past_text': '',
'mask_prompts': None,
'tokenizer': tokenizer,
}
return_dict = model.predict_forward(**input_dict)
answer = return_dict["From the published model card. Full card on the HuggingFace links in the sidebar.
Using it via the API
Once AxForge deploys sa2va for you, it answers on the OpenAI-compatible API — the same base URL and keys as every other model. (sa2va below is illustrative; you get the exact model name on deployment.)
$ curl -sS https://api.axforge.ai/v1/chat/completions \
-H "Authorization: Bearer $AXFORGE_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"sa2va","messages":[{"role":"user","content":"Hello"}]}'
Create an account — your API key is available in the console. 3M free tokens every 30 days with every new account.