We introduce InternVL2.5-MPO, an advanced multimodal large language model (MLLM) series that demonstrates superior overall performance. This series builds upon InternVL2.5 and Mixed Preference Optimization.
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InternVL 2.5 Family
In the following table, we provide an overview of the InternVL2.5-MPO series.
As shown in the following figure, InternVL2.5-MPO retains the same model architecture as InternVL 2.5 and its predecessors, InternVL 1.5 and 2.0, following the "ViT-MLP-LLM" paradigm. In this new version, we integrate a newly incrementally pre-trained InternViT with various pre-trained LLMs, including InternLM 2.5 and Qwen 2.5, using a randomly initialized MLP projector.
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As in the previous version, we applied a pixel unshuffle operation, reducing the number of visual tokens to one-quarter of the original. Besides, we adopted a similar dynamic resolution strategy as InternVL 1.5, dividing images into tiles of 448×448 pixels. The key difference, starting from InternVL 2.0, is that we additionally introduced support for multi-image and video data.
Key Designs
Multi-Modal Preference Dataset
MMPR is a large-scale and high-quality multimodal reasoning preference dataset. This dataset includes about 3 million samples.
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To construct this dataset, we propose an efficient data construction pipeline. Specifically, we categorize the multimodal data into samples with clear ground truths and samples without clear ground truths.
For samples with clear ground truths:
the model is prompted to first provide the reasoning process and then give the final answer in the format like Final Answer: ***.
Responses matching the ground truth answer constitute the positive set \(\mathcal{Y}_p\), while those that do not match make up the negative set \(\mathcal{Y}_n\). Additionally, responses that fail to provide a clear final answer are also merged into \(\mathcal{Y}_n\).
Given these responses labeled as positive or negative, we build the preference pairs by selecting a chosen response \(y_c\) from \(\mathcal{Y}_p\) and a negative response \(y_r\) from \(\mathcal{Y}_n\).
For samples without clear ground truths:
we propose a simple yet effective method: Dropout Next-Token Prediction (Dropout NTP).
Specifically, we use the responses generated by InternVL2-8B as chosen answers.
Given the chosen answer, we truncate it by half and then prompt InternVL2-8B to complete the remaining
portion of the truncated answer without access to the image input.
This generated completion serves as the rejected answer for the paired sample.
It is worth noting that while the responses generated by InternVL2-8B may not be perfect,
the completions generated without the image input will introduce more hallucinations than those
generated with the image input.
Therefore, the partial order relationship between the chosen and rejected responses holds true.
The data construction pipeline is open-sourced, see more details in our document.
Mixed Preference Optimization
The key insight behind MPO is that an effective PO process should enable the model to learn the relative preference between pairs of responses, the absolute quality of individual responses, and the process for generating preferred responses. We define the training objective as a combination of
preference loss \(\mathcal{L}{\text{p}}\),
quality loss \(\mathcal{L}{\text{q}}\),
and generation loss \(\mathcal{L}_{\text{g}}\),
referred to as Mixed Preference Optimization:
where \(w_{*}\) represents the weight assigned to each loss component.
In this work, we empirically compare different variants of preference loss.
Based on the experimental results, we use DPO as our preference loss and BCO as our quality loss.
Specifically, the DPO serves as the preference loss to enable the model to learn the
relative preference between chosen and rejected responses.
This algorithm optimizes the following loss function:
where \(\beta\) is the KL penalty coefficient, and \(x\), \(y_c\), and \(y_r\) are user query, chosen response, and rejected response, respectively.
The policy model \(\pi_\theta\) is initialized from model \(\pi_0\).
Additionally, the BCO loss is employed as the quality loss, which helps the model to understand the absolute quality of individual responses.
The loss function is defined as:
where \(\mathcal{L}{\text{q}}^{+}\) and \(\mathcal{L}{\text{q}}^{+}\) represent the loss for chosen and rejected responses, respectively.
Each response type's loss is calculated independently, requiring the model to differentiate the absolute quality of individual responses. The loss terms are given by:
where \(\delta\) represents the reward shift, calculated as the moving average of previous rewards to stabilize training.
Finally, the SFT loss is used as the generation loss to help the model learn the generation process of preferred responses.
The loss function is defined as:
To comprehensively compare InternVL's performance before and after MPO, we employ the benchmarks from OpenCompass Learderboard, including both well-established classic datasets and newly introduced ones. These benchmarks span a wide range of categories, aiming to provide a thorough and balanced assessment of InternVL’s capabilities across various multimodal tasks. We provide the evaluation results in the tables behind.
Model
Avg.
MMBench v1.1
MMStar
MMMU
MathVista
HallusionBench
AI2D
OCRBench
MMVet
InternVL2-5-1B
54.9
66.5
51.3
41.2
47.1
39.4
69.0
77.4
47.2
InternVL2-5-1B-MPO
56.4
67.2
49.7
40.8
53.0
40.0
69.4
83.6
47.2
InternVL2-5-2B
59.9
70.9
54.3
43.2
51.1
42.3
74.9
80.2
62.6
InternVL2-5-2B-MPO
62.0
71.6
55.0
45.0
56.4
43.0
75.3
84.2
65.4
InternVL2-5-4B
65.1
78.2
58.7
51.8
60.8
46.6
81.4
82.0
61.5
InternVL2-5-4B-MPO
67.6
78.6
60.2
51.6
65.3
47.8
82.0
88.0
67.1
InternVL2-5-8B
68.9
82.5
63.2
56.2
64.5
49.0
84.6
82.1
62.8
InternVL2-5-8B-MPO
70.4
82.4
65.7
54.9
68.9
51.4
84.5
88.3
66.9
InternVL2-5-26B
71.6
84.6
66.5
60.7
68.0
55.8
86.2
85.4
65.4
InternVL2-5-26B-MPO
72.7
84.2
67.2
57.7
72.8
55.3
86.2
91.2
67.1
InternVL2-5-38B
73.5
85.4
68.5
64.6
72.4
57.9
87.6
84.1
67.2
InternVL2-5-38B-MPO
75.5
85.6
69.8
64.1
73.8
61.5
88.1
88.5
72.5
InternVL2-5-78B
75.2
87.5
69.5
70.0
70.6
57.4
89.1
85.3
71.8
InternVL2-5-78B-MPO
76.6
87.3
73.1
68.3
73.8
58.7
89.3
91.2
71.4
Quick Start
We provide an example code to run InternVL2_5-2B-MPO using transformers.
Please use transformers>=4.37.2 to ensure the model works normally.
The reason for writing the code this way is to avoid errors that occur during multi-GPU inference due to tensors not being on the same device. By ensuring that the first and last layers of the large language model (LLM) are on the same device, we prevent such errors.
python
1import math
2import torch
3from transformers import AutoTokenizer, AutoModel
45defsplit_model(model_name):6 device_map ={}7 world_size = torch.cuda.device_count()8 num_layers ={9'InternVL2_5-1B':24,'InternVL2_5-2B':24,'InternVL2_5-4B':36,'InternVL2_5-8B':32,10'InternVL2_5-26B':48,'InternVL2_5-38B':64,'InternVL2_5-78B':80}[model_name]11# Since the first GPU will be used for ViT, treat it as half a GPU.12 num_layers_per_gpu = math.ceil(num_layers /(world_size -0.5))13 num_layers_per_gpu =[num_layers_per_gpu]* world_size
14 num_layers_per_gpu[0]= math.ceil(num_layers_per_gpu[0]*0.5)15 layer_cnt =016for i, num_layer inenumerate(num_layers_per_gpu):17for j inrange(num_layer):18 device_map[f'language_model.model.layers.{layer_cnt}']= i
19 layer_cnt +=120 device_map['vision_model']=021 device_map['mlp1']=022 device_map['language_model.model.tok_embeddings']=023 device_map['language_model.model.embed_tokens']=024 device_map['language_model.output']=025 device_map['language_model.model.norm']=026 device_map['language_model.model.rotary_emb']=027 device_map['language_model.lm_head']=028 device_map[f'language_model.model.layers.{num_layers -1}']=02930return device_map
3132path ="OpenGVLab/InternVL2_5-2B-MPO"33device_map = split_model('InternVL2_5-2B')34model = AutoModel.from_pretrained(35 path,36 torch_dtype=torch.bfloat16,37 low_cpu_mem_usage=True,38 use_flash_attn=True,39 trust_remote_code=True,40 device_map=device_map).eval()
Inference with Transformers
python
1import numpy as np
2import torch
3import torchvision.transforms as T
4from decord import VideoReader, cpu
5from PIL import Image
6from torchvision.transforms.functional import InterpolationMode
7from transformers import AutoModel, AutoTokenizer
89IMAGENET_MEAN =(0.485,0.456,0.406)10IMAGENET_STD =(0.229,0.224,0.225)1112defbuild_transform(input_size):13 MEAN, STD = IMAGENET_MEAN, IMAGENET_STD
14 transform = T.Compose([15 T.Lambda(lambda img: img.convert('RGB')if img.mode !='RGB'else img),16 T.Resize((input_size, input_size), interpolation=InterpolationMode.BICUBIC),17 T.ToTensor(),18 T.Normalize(mean=MEAN, std=STD)19])20return transform
2122deffind_closest_aspect_ratio(aspect_ratio, target_ratios, width, height, image_size):23 best_ratio_diff =float('inf')24 best_ratio =(1,1)25 area = width * height
26for ratio in target_ratios:27 target_aspect_ratio = ratio[0]/ ratio[1]28 ratio_diff =abs(aspect_ratio - target_aspect_ratio)29if ratio_diff < best_ratio_diff:30 best_ratio_diff = ratio_diff
31 best_ratio = ratio
32elif ratio_diff == best_ratio_diff:33if area >0.5* image_size * image_size * ratio[0]* ratio[1]:34 best_ratio = ratio
35return best_ratio
3637defdynamic_preprocess(image, min_num=1, max_num=12, image_size=448, use_thumbnail=False):38 orig_width, orig_height = image.size
39 aspect_ratio = orig_width / orig_height
4041# calculate the existing image aspect ratio42 target_ratios =set(43(i, j)for n inrange(min_num, max_num +1)for i inrange(1, n +1)for j inrange(1, n +1)if44 i * j <= max_num and i * j >= min_num)45 target_ratios =sorted(target_ratios, key=lambda x: x[0]* x[1])4647# find the closest aspect ratio to the target48 target_aspect_ratio = find_closest_aspect_ratio(49 aspect_ratio, target_ratios, orig_width, orig_height, image_size)5051# calculate the target width and height52 target_width = image_size * target_aspect_ratio[0]53 target_height = image_size * target_aspect_ratio[1]54 blocks = target_aspect_ratio[0]* target_aspect_ratio[1]5556# resize the image57 resized_img = image.resize((target_width, target_height))58 processed_images =[]59for i inrange(blocks):60 box =(61(i %(target_width // image_size))* image_size,62(i //(target_width // image_size))* image_size,63((i %(target_width // image_size))+1)* image_size,64((i //(target_width // image_size))+1)* image_size
65)66# split the image67 split_img = resized_img.crop(box)68 processed_images.append(split_img)69assertlen(processed_images)== blocks
70if use_thumbnail andlen(processed_images)!=1:71 thumbnail_img = image.resize((image_size, image_size))72 processed_images.append(thumbnail_img)73return processed_images
7475defload_image(image_file, input_size=448, max_num=12):76 image = Image.open(image_file).convert('RGB')77 transform = build_transform(input_size=input_size)78 images = dynamic_preprocess(image, image_size=input_size, use_thumbnail=True, max_num=max_num)79 pixel_values =[transform(image)for image in images]80 pixel_values = torch.stack(pixel_values)81return pixel_values
8283# If you want to load a model using multiple GPUs, please refer to the `Multiple GPUs` section.84path ='OpenGVLab/InternVL2_5-2B-MPO'85model = AutoModel.from_pretrained(86 path,87 torch_dtype=torch.bfloat16,88 low_cpu_mem_usage=True,89 use_flash_attn=True,90 trust_remote_code=True).eval().cuda()91tokenizer = AutoTokenizer.from_pretrained(path, trust_remote_code=True, use_fast=False)9293# set the max number of tiles in `max_num`94pixel_values = load_image('./examples/image1.jpg', max_num=12).to(torch.bfloat16).cuda()95generation_config =dict(max_new_tokens=1024, do_sample=True)9697# pure-text conversation (纯文本对话)98question ='Hello, who are you?'99response, history = model.chat(tokenizer,None, question, generation_config, history=None, return_history=True)100print(f'User: {question}\nAssistant: {response}')101102question ='Can you tell me a story?'103response, history = model.chat(tokenizer,None, question, generation_config, history=history, return_history=True)104print(f'User: {question}\nAssistant: {response}')105106# single-image single-round conversation (单图单轮对话)107question ='<image>\nPlease describe the image shortly.'108response = model.chat(tokenizer, pixel_values, question, generation_config)109print(f'User: {question}\nAssistant: {response}')110111# single-image multi-round conversation (单图多轮对话)112question ='<image>\nPlease describe the image in detail.'113response, history = model.chat(tokenizer, pixel_values, question, generation_config, history=None, return_history=True)114print(f'User: {question}\nAssistant: {response}')115116question ='Please write a poem according to the image.'117response, history = model.chat(tokenizer, pixel_values, question, generation_config, history=history, return_history=True)118print(f'User: {question}\nAssistant: {response}')119120# multi-image multi-round conversation, combined images (多图多轮对话,拼接图像)121pixel_values1 = load_image('./examples/image1.jpg', max_num=12).to(torch.bfloat16).cuda()122pixel_values2 = load_image('./examples/image2.jpg', max_num=12).to(torch.bfloat16).cuda()123pixel_values = torch.cat((pixel_values1, pixel_values2), dim=0)124125question ='<image>\nDescribe the two images in detail.'126response, history = model.chat(tokenizer, pixel_values, question, generation_config,127 history=None, return_history=True)128print(f'User: {question}\nAssistant: {response}')129130question ='What are the similarities and differences between these two images.'131response, history = model.chat(tokenizer, pixel_values, question, generation_config,132 history=history, return_history=True)133print(f'User: {question}\nAssistant: {response}')134135# multi-image multi-round conversation, separate images (多图多轮对话,独立图像)136pixel_values1 = load_image('./examples/image1.jpg', max_num=12).to(torch.bfloat16).cuda()137pixel_values2 = load_image('./examples/image2.jpg', max_num=12).to(torch.bfloat16).cuda()138pixel_values = torch.cat((pixel_values1, pixel_values2), dim=0)139num_patches_list =[pixel_values1.size(0), pixel_values2.size(0)]140141question ='Image-1: <image>\nImage-2: <image>\nDescribe the two images in detail.'142response, history = model.chat(tokenizer, pixel_values, question, generation_config,143 num_patches_list=num_patches_list,144 history=None, return_history=True)145print(f'User: {question}\nAssistant: {response}')146147question ='What are the similarities and differences between these two images.'148response, history = model.chat(tokenizer, pixel_values, question, generation_config,149 num_patches_list=num_patches_list,150 history=history, return_history=True)151print(f'User: {question}\nAssistant: {response}')152153# batch inference, single image per sample (单图批处理)154pixel_values1 = load_image('./examples/image1.jpg', max_num=12).to(torch.bfloat16).cuda()155pixel_values2 = load_image('./examples/image2.jpg', max_num=12).to(torch.bfloat16).cuda()156num_patches_list =[pixel_values1.size(0), pixel_values2.size(0)]157pixel_values = torch.cat((pixel_values1, pixel_values2), dim=0)158159questions =['<image>\nDescribe the image in detail.']*len(num_patches_list)160responses = model.batch_chat(tokenizer, pixel_values,161 num_patches_list=num_patches_list,162 questions=questions,163 generation_config=generation_config)164for question, response inzip(questions, responses):165print(f'User: {question}\nAssistant: {response}')166167# video multi-round conversation (视频多轮对话)168defget_index(bound, fps, max_frame, first_idx=0, num_segments=32):169if bound:170 start, end = bound[0], bound[1]171else:172 start, end =-100000,100000173 start_idx =max(first_idx,round(start * fps))174 end_idx =min(round(end * fps), max_frame)175 seg_size =float(end_idx - start_idx)/ num_segments
176 frame_indices = np.array([177int(start_idx +(seg_size /2)+ np.round(seg_size * idx))178for idx inrange(num_segments)179])180return frame_indices
181182defload_video(video_path, bound=None, input_size=448, max_num=1, num_segments=32):183 vr = VideoReader(video_path, ctx=cpu(0), num_threads=1)184 max_frame =len(vr)-1185 fps =float(vr.get_avg_fps())186187 pixel_values_list, num_patches_list =[],[]188 transform = build_transform(input_size=input_size)189 frame_indices = get_index(bound, fps, max_frame, first_idx=0, num_segments=num_segments)190for frame_index in frame_indices:191 img = Image.fromarray(vr[frame_index].asnumpy()).convert('RGB')192 img = dynamic_preprocess(img, image_size=input_size, use_thumbnail=True, max_num=max_num)193 pixel_values =[transform(tile)for tile in img]194 pixel_values = torch.stack(pixel_values)195 num_patches_list.append(pixel_values.shape[0])196 pixel_values_list.append(pixel_values)197 pixel_values = torch.cat(pixel_values_list)198return pixel_values, num_patches_list
199200video_path ='./examples/red-panda.mp4'201pixel_values, num_patches_list = load_video(video_path, num_segments=8, max_num=1)202pixel_values = pixel_values.to(torch.bfloat16).cuda()203video_prefix =''.join([f'Frame{i+1}: <image>\n'for i inrange(len(num_patches_list))])204question = video_prefix +'What is the red panda doing?'205# Frame1: <image>\nFrame2: <image>\n...\nFrame8: <image>\n{question}206response, history = model.chat(tokenizer, pixel_values, question, generation_config,207 num_patches_list=num_patches_list, history=None, return_history=True)208print(f'User: {question}\nAssistant: {response}')209210question ='Describe this video in detail.'211response, history = model.chat(tokenizer, pixel_values, question, generation_config,212 num_patches_list=num_patches_list, history=history, return_history=True)213print(f'User: {question}\nAssistant: {response}')
Streaming Output
Besides this method, you can also use the following code to get streamed output.
python
1from transformers import TextIteratorStreamer
2from threading import Thread
34# Initialize the streamer5streamer = TextIteratorStreamer(tokenizer, skip_prompt=True, skip_special_tokens=True, timeout=10)6# Define the generation configuration7generation_config =dict(max_new_tokens=1024, do_sample=False, streamer=streamer)8# Start the model chat in a separate thread9thread = Thread(target=model.chat, kwargs=dict(10 tokenizer=tokenizer, pixel_values=pixel_values, question=question,11 history=None, return_history=False, generation_config=generation_config,12))13thread.start()1415# Initialize an empty string to store the generated text16generated_text =''17# Loop through the streamer to get the new text as it is generated18for new_text in streamer:19if new_text == model.conv_template.sep:20break21 generated_text += new_text
22print(new_text, end='', flush=True)# Print each new chunk of generated text on the same line
Finetune
Many repositories now support fine-tuning of the InternVL series models, including InternVL, SWIFT, XTurner, and others. Please refer to their documentation for more details on fine-tuning.
Deployment
LMDeploy
LMDeploy is a toolkit for compressing, deploying, and serving LLMs & VLMs.
pip install lmdeploy>=0.6.4
LMDeploy abstracts the complex inference process of multi-modal Vision-Language Models (VLM) into an easy-to-use pipeline, similar to the Large Language Model (LLM) inference pipeline.
If ImportError occurs while executing this case, please install the required dependency packages as prompted.
Multi-images Inference
When dealing with multiple images, you can put them all in one list. Keep in mind that multiple images will lead to a higher number of input tokens, and as a result, the size of the context window typically needs to be increased.
There are two ways to do the multi-turn conversations with the pipeline. One is to construct messages according to the format of OpenAI and use above introduced method, the other is to use the pipeline.chat interface.
LMDeploy's api_server enables models to be easily packed into services with a single command. The provided RESTful APIs are compatible with OpenAI's interfaces. Below are an example of service startup:
This project is released under the MIT License. This project uses the pre-trained internlm2_5-1_8b-chat as a component, which is licensed under the Apache License 2.0.
Citation
If you find this project useful in your research, please consider citing:
BibTeX
1@article{wang2024mpo,
2 title={Enhancing the Reasoning Ability of Multimodal Large Language Models via Mixed Preference Optimization},
3 author={Wang, Weiyun and Chen, Zhe and Wang, Wenhai and Cao, Yue and Liu, Yangzhou and Gao, Zhangwei and Zhu, Jinguo and Zhu, Xizhou and Lu, Lewei and Qiao, Yu and Dai, Jifeng},
4 journal={arXiv preprint arXiv:2411.10442},
5 year={2024}
6}
7@article{chen2024expanding,
8 title={Expanding Performance Boundaries of Open-Source Multimodal Models with Model, Data, and Test-Time Scaling},
9 author={Chen, Zhe and Wang, Weiyun and Cao, Yue and Liu, Yangzhou and Gao, Zhangwei and Cui, Erfei and Zhu, Jinguo and Ye, Shenglong and Tian, Hao and Liu, Zhaoyang and others},
10 journal={arXiv preprint arXiv:2412.05271},
11 year={2024}
12}
13@article{chen2024far,
14 title={How Far Are We to GPT-4V? Closing the Gap to Commercial Multimodal Models with Open-Source Suites},
15 author={Chen, Zhe and Wang, Weiyun and Tian, Hao and Ye, Shenglong and Gao, Zhangwei and Cui, Erfei and Tong, Wenwen and Hu, Kongzhi and Luo, Jiapeng and Ma, Zheng and others},
16 journal={arXiv preprint arXiv:2404.16821},
17 year={2024}
18}
19@inproceedings{chen2024internvl,
20 title={Internvl: Scaling up vision foundation models and aligning for generic visual-linguistic tasks},
21 author={Chen, Zhe and Wu, Jiannan and Wang, Wenhai and Su, Weijie and Chen, Guo and Xing, Sen and Zhong, Muyan and Zhang, Qinglong and Zhu, Xizhou and Lu, Lewei and others},
22 booktitle={Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition},
23 pages={24185--24198},
24 year={2024}
25}