Update README.md

README.md

@@ -11,5 +11,52 @@ Long context capability can **zero-shot transfer** from language to vision.
 
 LongVA can process **2000** frames or over **200K** visual tokens. It achieves **state-of-the-art** performance on Video-MME among 7B models.
 
+# Usage
+
+First follow the instructions in [our repo](https://github.com/EvolvingLMMs-Lab/LongVA) to install relevant packages.
+
+```python
+from longva.model.builder import load_pretrained_model
+from longva.mm_utils import tokenizer_image_token, process_images
+from longva.constants import IMAGE_TOKEN_INDEX
+from PIL import Image
+from decord import VideoReader, cpu
+import torch
+import numpy as np
+# fix seed
+torch.manual_seed(0)
+
+model_path = "lmms-lab/LongVA-7B-DPO"
+image_path = "local_demo/assets/lmms-eval.png"
+video_path = "local_demo/assets/dc_demo.mp4"
+max_frames_num = 16 # you can change this to several thousands so long you GPU memory can handle it :)
+gen_kwargs = {"do_sample": True, "temperature": 0.5, "top_p": None, "num_beams": 1, "use_cache": True, "max_new_tokens": 1024}
+tokenizer, model, image_processor, _ = load_pretrained_model(model_path, None, "llava_qwen", device_map="cuda:0")
+
+#image input
+prompt = "<|im_start|>system\nYou are a helpful assistant.<|im_end|>\n<|im_start|>user\n<image>\nDescribe the image in details.<|im_end|>\n<|im_start|>assistant\n"
+input_ids = tokenizer_image_token(prompt, tokenizer, IMAGE_TOKEN_INDEX, return_tensors="pt").unsqueeze(0).to(model.device)
+image = Image.open(image_path).convert("RGB")
+images_tensor = process_images([image], image_processor, model.config).to(model.device, dtype=torch.float16)
+with torch.inference_mode():
+    output_ids = model.generate(input_ids, images=[images_tensor], image_sizes=[image.size], modalities=["image"], **gen_kwargs)
+outputs = tokenizer.batch_decode(output_ids, skip_special_tokens=True)[0].strip()
+print(outputs)
+print("-"*50)
+
+#video input
+prompt = "<|im_start|>system\nYou are a helpful assistant.<|im_end|>\n<|im_start|>user\n<image>\nGive a detailed caption of the video as if I am blind.<|im_end|>\n<|im_start|>assistant\n"
+input_ids = tokenizer_image_token(prompt, tokenizer, IMAGE_TOKEN_INDEX, return_tensors="pt").unsqueeze(0).to(model.device)
+vr = VideoReader(video_path, ctx=cpu(0))
+total_frame_num = len(vr)
+uniform_sampled_frames = np.linspace(0, total_frame_num - 1, max_frames_num, dtype=int)
+frame_idx = uniform_sampled_frames.tolist()
+frames = vr.get_batch(frame_idx).asnumpy()
+video_tensor = image_processor.preprocess(frames, return_tensors="pt")["pixel_values"].to(model.device, dtype=torch.float16)
+with torch.inference_mode():
+    output_ids = model.generate(input_ids, images=[video_tensor],  modalities=["video"], **gen_kwargs)
+outputs = tokenizer.batch_decode(output_ids, skip_special_tokens=True)[0].strip()
+print(outputs)
+```