Log videos

Log and track video data automatically in Weave traces using moviepy for playback and analysis in the UI.

Weave automatically logs videos using moviepy. This allows you to pass video inputs and outputs to traced functions, and Weave will automatically handle uploading and storing video data.

Video support is currently only available in Python.

Usage prerequisites

1. Install weave and moviepy==1.0.3.
2. Create a W&B account.

Supported video types

Weave recognizes moviepy video clip objects, such as:

• A VideoFileClip loaded from a video file
• In-memory clips like ImageClip, ColorClip, and TextClip

Direct upload of file-based clips

If your clip is a VideoFileClip and has a valid filename with a supported extension, Weave will upload the file directly.

Supported file extensions:

• .mp4
• .webm
• .gif

In-memory clip support

If the video object is in memory (no file on disk), Weave will encode it as an .mp4 file and handle the upload automatically. This applies to clips of the following type:

• ImageClip
• ColorClip
• TextClip

Example: Trace a video function

The following code sample demonstrates how to trace a video processing function in Weave. The code sample:

1. Initializes a Weave project video-test.
2. Defines a get_video function tracked as a weave.op that extracts a 1 second subclip of the loaded VideoFileClip as a VideoClip.
3. Uploads and tracks the clip in Weave.
4. Automatically generates a dummy MP4 video if none is found.

To avoid thread-safety issues, always pass the path to VideoFileClip objects instead of creating them outside the Weave op.

Before you use the following code snippet, complete the usage prerequisites.

import os
import weave
from moviepy.editor import VideoFileClip, ColorClip, VideoClip

# Update to your project name, or create a new project named 'video-test'
weave.init('video-test')

@weave.op
def get_video(clip: VideoFileClip) -> VideoClip:
    """Process a video by path rather than by passing the clip directly.

    This ensures that the VideoFileClip is created and managed within the
    Weave op's thread context, avoiding thread-safety issues.
    """
    new_clip = clip.subclip(0, 1)
    return new_clip

if __name__ == "__main__":
    os.makedirs("videos", exist_ok=True)

    # Update the path to point to your MP4 file
    video_path = './videos/example.mp4'

    # Generate a dummy video if it doesn't exist
    # Dummy video contents: A red square that displays for 5 seconds
    if not os.path.isfile(video_path):
        print("No video found. Creating dummy video...")
        dummy_clip = ColorClip(size=(640, 480), color=(255, 0, 0), duration=5)
        dummy_clip.write_videofile(video_path, fps=24)

    clip = VideoFileClip(video_path, has_mask=False, audio=True)
    get_video(clip) 

When the code sample runs successfully, you can view your video by clicking the link in the Traces table of your project.