Official repository for the paper "3DGStream: On-the-fly Training of 3D Gaussians for Efficient Streaming of Photo-Realistic Free-Viewpoint Videos".

3DGStream: On-the-fly Training of 3D Gaussians for Efficient Streaming of Photo-Realistic Free-Viewpoint Videos
Jiakai Sun, Han Jiao, Guangyuan Li, Zhanjie Zhang, Lei Zhao, Wei Xing
CVPR 2024 Highlight
Project | Paper | Suppl. | Bibtex | Viewer

• Open-source 3DGStream Viewer

  • Free-Viewpoint Video

• Unorganized code with few instructions (around May 2024)

  • Pre-Release

• Refactored code with added comments (after CVPR 2024)

• 3DGStream v2 (hopefully in 2025)

1. Follow the instructions in gaussian-splatting to setup the environment and submodules, after that, you need to install tiny-cuda-nn.

   You can use the same Python environment configured for gaussian-splatting. However, it is necessary to install tiny-cuda-nn and reinstall the submodules/diff-gaussian-rasterization by running pip install submodules/diff-gaussian-rasterization. Additionally, we recommend using PyTorch version 2.0 or higher for enhanced performance, as we utilize torch.compile. If you are using a PyTorch version lower than 2.0, you may need to comment out the lines of the code where torch.compile is used.

   The code is tested on:

   OS: Ubuntu 22.04
   GPU: RTX A6000/3090
   Driver: 535.86.05
   CUDA: 11.8
   Python: 3.8
   Pytorch: 2.0.1+cu118
   tinycudann: 1.7
   

2. Follow the instructions in gaussian-splatting to create your COLMAP dataset based on the images of the timestep 0 , which will end-up like:

   <frame000000>
   |---images
   |   |---<image 0>
   |   |---<image 1>
   |   |---...
   |---distorted
   |	|---sparse
   |       |---0
   |           |---cameras.bin
   |           |---images.bin
   |           |---points3D.bin
   |---sparse
       |---0
           |---cameras.bin
           |---images.bin
           |---points3D.bin
   

   You can use test/flame_steak_suite/frame000000 for experiment on the flame steak scene.

3. Follow the instructions in gaussian-splatting to get a high-quality init_3dgs (sh_degree = 1, i.e., train with --sh_degree 1) from the above colmap dataset, which will end-up like:

      <init_3dgs_dir>
      |---point_cloud
      |   |---iteration_7000
      |   |   |---point_cloud.ply
      |   |---iteration_15000
      |   |---...
      |---...   
   

   You can use test/flame_steak_suite/flame_steak_init for experiment on the flame steak scene.

   Since the training of 3DGStream is orthogonal to that of init_3dgs, you are free to use any method that enhances the quality of init_3dgs, provided that the resulting ply file remains compatible with the original gaussian-splatting.

4. Prepare the multi-view video dataset:

   1. Extract the frames and organize them like this:

      <scene>
      |---frame000001
      |   |---<image 0>
      |   |---<image 1>
      |   |---...
      |---frame000002  
      |---...
      |---frame000299
      

      If you intend to use the data we have prepared in the test/flame_steak_suite, ensure that the images are named following the pattern cam00.png, ..., cam20.png. This is necessary because COLMAP references images by their file names.

      For convenience, we assume that you extract the frames of the flame steak scene into dataset/flame_steak. This means your folder structure should look like this:

      dataset/flame_steak
      |---frame000001
      |   |---cam00.png
      |   |---cam01.png
      |   |---...
      |---frame000002  
      |---...
      |---frame000299
      

   2. Copy the camera infos by python scripts/copy_cams.py --source <frame000000> --scene <scene>:

      <scene>
      |---frame000001
      |   |---sparse
      |   |   |---...
      |   |---<image 0>
      |   |---<image 1>
      |   |---...
      |---frame000002  
      |---frame000299
      |---distorted
      |   |---...
      |---...      
      

      You can run

      python scripts/copy_cams.py --source test/flame_steak_suite/frame000000 --scene dataset/flame_steak
      

      to prepare for conducting experiment on the flame steak scene.

   3. Undistort the images by python convert_frames.py -s <scene> --resize, then the dataset will end-up like this:

      <scene>
      |---frame000001
      |   |---sparse
      |   |---images
      |       |---<undistorted image 0>
      |       |---<undistorted image 1>
      |       |---....
      |   |---<image 0>
      |   |---<image 1>
      |   |---...
      |---frame000002  
      |---...
      |---frame000299
      

      You can run

      python convert_frames.py --scene dataset/flame_steak --resize
      

      to prepare for conducting experiment on the flame steak scene.

5. Warm-up the NTC

   Please refer to the scripts/cache_warmup.ipynb notebook to perform a warm-up of the NTC.

   For better performance, it's crucial to define the corners of the Axis-Aligned Bounding Box that approximately enclose your scene. For instance, in a scene like flame salmon, the AABB should encompass the room while excluding any external landscape elements. To set the coordinates of the AABB corners, you should directly hard-code them into the get_xyz_bound function.

   If you find that the loss is NaN when the NTC is warm-uped, please refer to this issue for a solution.

6. GO!

   Everything is set up, just run

   python train_frames.py --read_config --config_path <config_path> -o <output_dir> -m <init_3dgs_dir>  -v <scene> --image <images_dir> --first_load_iteration <first_load_iteration>
   

   Parameter explanations:

   • <config_path>: We provide a configuration file containing all necessary parameters, available at test/flame_steak_suite/cfg_args.json.
   • <init_3dgs_dir>: Please refer to the section 2 of this guidance.
   • <scene>: Please refer to the section 4.2 of this guidance.
   • <images_dir>: Typically named images, images_2, or images_4. 3DGStream will use the images located at <scene>/<frame[id]>/<images_dir> as input.
   • <first_load_iteration>: 3DGStream will initialize the 3DGS using the point cloud at <init_3dgs_dir>/<point_cloud>/iteration_<first_load_iteration>/point_cloud.ply.
   • Use --eval when you have a test/train split. You may need to review and modify readColmapSceneInfo in scene/dataset_renders.py accordingly.
   • Specify --resolution only when necessary, as reading and resizing large images is time-consuming. Consider resizing the images before 3DGStream processes them.
   • About NTC:
     • --ntc_conf_path: Set this to the path of the NTC configuration file (see scripts/cache_warmup.ipynb, configs/cache/ and tiny-cuda-nn).
     • --ntc_path: Set this to the path of the pre-warmed parameters (see scripts/cache_warmup.ipynb).

   You can run

   python train_frames.py --read_config --config_path test/flame_steak_suite/cfg_args.json -o output/Code-Release -m test/flame_steak_suite/flame_steak_init/ -v <scene> --image images_2 --first_load_iteration 15000 --quiet
   

   to conduct the experiments on the flame steak scene.

7. Evaluate Performance

   • PSNR: Average among all test images

   • Per-frame Storage: Average among all frames (including the first frame)

     For a multi-view videos that has 300 frames, the per-frame storage is $$\frac{(\text{init3dgs})+299*(\text{NTC}+\text{new3dgs})}{300}$$​

   • Per-frame Training Time: Average among all frames (including the first frame)

   • Rendering Speed

     There are serval ways to evaluate the rendering speed:

     • SIBR-Viewer (As presented in our paper)

       Integrate 3DGStream into SIBR-Viewer for an accurate measurement. If integration is too complex, approximate the rendering speed by:

       1. Use the SIBR-Viewer to render the init_3dgs and get the rendering speed

       2. Profiling query_ntc_eval using scripts/cache_profile.ipynb.

       3. Summing the measurements for an estimated total rendering speed, like this:

          Step	Overhead(ms)	FPS
          Render w/o NTC	2.56	390
          + Query NTC	0.62
          + Transformation	0.02
          + SH Rotation	1.46
          Total	4.46	215

          To isolate the overhead for each process, you can comment out the other parts of the code.

     • 3DGStreamViewer

       You can use scripts/extract_fvv.py to re-arrange the output of 3DGStream and render it with 3DGStreamViewer

     • Custom Script

       Write a script that loads all NTCs and additional_3dgs and renders the test image for every frame. For guidance, you can look at the implementation within 3DGStreamViewer

We acknowledge the foundational work of gaussian-splatting and tiny-cuda-nn, which form the basis of the 3DGStream code. Special thanks to Qiankun Gao for his feedback on the pre-release version.

@InProceedings{sun20243dgstream,
    author    = {Sun, Jiakai and Jiao, Han and Li, Guangyuan and Zhang, Zhanjie and Zhao, Lei and Xing, Wei},
    title     = {3DGStream: On-the-Fly Training of 3D Gaussians for Efficient Streaming of Photo-Realistic Free-Viewpoint Videos},
    booktitle = {Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR)},
    month     = {June},
    year      = {2024},
    pages     = {20675-20685}
}