Build and Use Video Generator

The Visual Pipeline and Platform Evaluation Tool includes a video generator that creates composite videos from images stored in subdirectories.

This guide is intended for developers working directly with the source code.

Build and start the tool:

make run-videogenerator

Make Changes

1. Change input images:

   Custom images can be used instead of the default sample images as follows:

   • Navigate to the images folder and create subfolders for new image categories, then place the relevant images inside those subfolders.

   • Open the config.json file located at video_generator/config.json.

   • Update the object_counts section to reference the new image folders. Existing categories (for example, cars or persons) should be replaced with the names of the new categories defined in the images folder:

     {
        "background_file": "/usr/src/app/background.gif",
        "base_image_dir": "/usr/src/app/images",
        "output_file": "output_file",
        "target_resolution": [1920, 1080],
        "frame_count": 300,
        "frame_rate": 30,
        "swap_percentage": 20,
        "object_counts": {
           "cars": 3,
           "persons": 3
        },
        "object_rotation_rate": 0.25,
        "object_scale_rate": 0.25,
        "object_scale_range": [0.25, 1],
        "encoding": "H264",
        "bitrate": 20000,
        "swap_rate": 1
     }
     

2. Configure parameters:

   The program uses a config.json file to customize the video generation process. Below is an example configuration:

   {
      "background_file": "/usr/src/app/background.gif",
      "base_image_dir": "/usr/src/app/images",
      "output_file": "output_file",
      "target_resolution": [1920, 1080],
      "frame_count": 300,
      "frame_rate": 30,
      "swap_percentage": 20,
      "object_counts": {
         "cars": 3,
         "persons": 3
      },
      "object_rotation_rate": 0.25,
      "object_scale_rate": 0.25,
      "object_scale_range": [0.25, 1],
      "encoding": "H264",
      "bitrate": 20000,
      "swap_rate": 1
   }
   

   Parameters in the config.json file can be configured as follows:

   • background_file: Path to a background image (GIF, PNG, and so on) used in composite frames.

   • base_image_dir: Path to the root directory containing categorized image subdirectories.

   • output_file: Base name for the generated video file. It is recommended not to provide a file extension and not to include . in the filename (for example, output_file).

   • target_resolution: Resolution of the output video in [width, height] format.

   • duration: Total duration of the generated video in seconds.

   • frame_count: Total number of frames in the generated video.

   • swap_percentage: Percentage of images that are swapped between frames.

   • object_counts: Dictionary specifying the number of images per category in each frame.

   • object_rotation_rate: Rate at which objects rotate per frame (for example, 0.25 means a quarter rotation per frame).

   • object_scale_rate: Rate at which the size of objects changes per frame (for example, 0.25 means the object size changes by 25% per frame).

   • object_scale_range: List specifying the minimum and maximum scale factors for the objects (for example, [0.25, 1] means objects can scale between 25% and 100% of their original size).

   • encoding: Video encoding format (for example, H264).

   • bitrate: Bitrate for video encoding, measured in kbps.

   • swap_interval: Frequency of image swapping within frames, in seconds.

   • Supported encodings and video formats:

     Encoding	Video Format
     H264	.mp4
     HEVC	.mp4
     VP8	.webm
     VP9	.webm
     AV1	.mkv
     MPEG4	.avi
     ProRes	.mov
     Theora	.ogg

Validation

1. Verify build success:

   • Logs should be checked for confirmation messages indicating that the microservice started successfully:

     docker compose logs videogenerator -f
     

• Expected result: An MP4 file is created under the shared/videos/video-generator folder.