Video Operations - Labellerr Documentation

Introduction

What are Keyframes?

Keyframes in video annotation are specific frames selected for annotation within a video file. Instead of annotating every frame, you can select key moments that represent important changes or events in the video.This approach:

Reduces annotation time and cost
Focuses on critical frames
Maintains annotation quality
Enables efficient video annotation workflows

Video Project Setup

Import Required Modules

Required Imports

from labellerr.client import LabellerrClient
from labellerr.core.projects import LabellerrProject
from labellerr.core.schemas import KeyFrame
from labellerr.core.exceptions import LabellerrError

Important: Keyframe operations are only available for video projects. The LabellerrProject class automatically detects video projects and provides these methods.

Adding or Updating Keyframes

KeyFrame Schema

Before adding keyframes, you need to understand the KeyFrame structure:

KeyFrame Structure

from labellerr.core.schemas import KeyFrame

keyframe = KeyFrame(
    frame_number=100,      # Frame number (must be >= 0)
    is_manual=True,        # Whether it's manually selected
    method="manual",       # Selection method
    source="manual"        # Source of the keyframe
)

KeyFrame Parameters

Parameter	Type	Required	Description
`frame_number`	int	Yes	Frame number in the video (must be ≥ 0)
`is_manual`	bool	No	Whether keyframe was manually selected (default: True)
`method`	str	No	Selection method (default: “manual”)
`source`	str	No	Source of the keyframe (default: “manual”)

Add or Update Keyframes

You can add new keyframes or update existing ones using the same method:

Add/Update Keyframes

from labellerr.client import LabellerrClient
from labellerr.core.projects import LabellerrProject
from labellerr.core.schemas import KeyFrame

client = LabellerrClient(
    api_key='your_api_key',
    api_secret='your_api_secret',
    client_id='your_client_id'
)

try:
    # Get video project instance
    project = LabellerrProject(client=client, project_id="video_project_id")
    
    # Define keyframes to add/update
    keyframes = [
        KeyFrame(frame_number=0, is_manual=True, method="manual", source="manual"),
        KeyFrame(frame_number=100, is_manual=True, method="manual", source="manual"),
        KeyFrame(frame_number=200, is_manual=True, method="manual", source="manual")
    ]
    
    # Add or update keyframes for a specific video file
    result = project.add_or_update_keyframes(
        file_id="video_file_id",
        keyframes=keyframes
    )
    
    print(f"Keyframes added/updated successfully: {result}")
    
except LabellerrError as e:
    print(f"Failed to add/update keyframes: {str(e)}")

Behavior:

If a keyframe with the same frame_number already exists, it will be updated
If the frame_number is new, a new keyframe will be added

Batch Keyframe Creation

You can efficiently add multiple keyframes at once:

Batch Keyframe Creation

from labellerr.core.schemas import KeyFrame

# Create keyframes at regular intervals (every 30 frames)
keyframes = []
for frame_num in range(0, 300, 30):  # 0, 30, 60, 90, ..., 270
    keyframes.append(
        KeyFrame(frame_number=frame_num, is_manual=True, method="manual", source="manual")
    )

project = LabellerrProject(client=client, project_id="video_project_id")

result = project.add_or_update_keyframes(
    file_id="video_file_id",
    keyframes=keyframes
)

print(f"Added {len(keyframes)} keyframes")

Deleting Keyframes

Delete Specific Keyframes

Remove keyframes by specifying their frame numbers:

Delete Keyframes

from labellerr.client import LabellerrClient
from labellerr.core.projects import LabellerrProject

client = LabellerrClient(
    api_key='your_api_key',
    api_secret='your_api_secret',
    client_id='your_client_id'
)

try:
    project = LabellerrProject(client=client, project_id="video_project_id")
    
    # Delete specific keyframes by frame number
    result = project.delete_keyframes(
        file_id="video_file_id",
        keyframes=[0, 100, 200]  # List of frame numbers to delete
    )
    
    print(f"Keyframes deleted successfully: {result}")
    
except LabellerrError as e:
    print(f"Failed to delete keyframes: {str(e)}")

Caution: Deleting keyframes also removes any annotations associated with those frames. This action cannot be undone.

Complete Workflow Example

End-to-End Keyframe Management

Complete Keyframe Workflow

from labellerr.client import LabellerrClient
from labellerr.core.projects import LabellerrProject
from labellerr.core.schemas import KeyFrame
from labellerr.core.exceptions import LabellerrError

# Initialize client
client = LabellerrClient(
    api_key='your_api_key',
    api_secret='your_api_secret',
    client_id='your_client_id'
)

try:
    # Step 1: Get video project
    project = LabellerrProject(client=client, project_id="video_project_id")
    print(f"Working with project: {project.project_id}")
    
    # Step 2: Add initial keyframes (every 60 frames for first 5 minutes at 30fps)
    initial_keyframes = [
        KeyFrame(frame_number=i, is_manual=True, method="manual", source="manual")
        for i in range(0, 9000, 60)  # 9000 frames = 5 min at 30fps
    ]
    
    result = project.add_or_update_keyframes(
        file_id="video_file_id",
        keyframes=initial_keyframes
    )
    print(f"Added {len(initial_keyframes)} keyframes")
    
    # Step 3: Update specific keyframes (e.g., adjust frame 1800)
    updated_keyframes = [
        KeyFrame(frame_number=1800, is_manual=True, method="manual", source="manual")
    ]
    
    result = project.add_or_update_keyframes(
        file_id="video_file_id",
        keyframes=updated_keyframes
    )
    print(f"Updated keyframe at frame 1800")
    
    # Step 4: Delete unwanted keyframes
    frames_to_delete = [3600, 7200]  # Remove keyframes at 2min and 4min marks
    result = project.delete_keyframes(
        file_id="video_file_id",
        keyframes=frames_to_delete
    )
    print(f"Deleted {len(frames_to_delete)} keyframes")
    
except LabellerrError as e:
    print(f"Error in keyframe workflow: {str(e)}")

Common Use Cases

Regular Interval Sampling

Select keyframes at regular intervals (e.g., every 30 frames) for consistent annotation coverage

Scene Change Detection

Use automated scene detection to identify keyframes at scene transitions

Event-Based Selection

Manually select keyframes at important events or actions in the video

Adaptive Sampling

Adjust keyframe density based on video content complexity

Best Practices

Keyframe Selection Guidelines

Optimal Keyframe Density

Low motion videos: 1 keyframe every 2-3 seconds
Medium motion videos: 1 keyframe every 1-2 seconds
High motion videos: 1 keyframe every 0.5-1 second
Critical events: Always include keyframes at important moments

Performance Considerations

Add keyframes in batches rather than one-by-one
Validate frame numbers before submission
Handle errors gracefully with try-except blocks
Consider video length and framerate when selecting intervals

Annotation Quality

Include keyframes that capture state changes
Ensure sufficient coverage for temporal tracking
Balance between annotation workload and quality
Review keyframe selection before starting annotation

Error Handling

Common Errors and Solutions

Error Handling Example

from labellerr.core.exceptions import LabellerrError

try:
    project = LabellerrProject(client=client, project_id="video_project_id")
    
    keyframes = [
        KeyFrame(frame_number=100, is_manual=True, method="manual", source="manual")
    ]
    
    result = project.add_or_update_keyframes(
        file_id="video_file_id",
        keyframes=keyframes
    )
    
except LabellerrError as e:
    if "not found" in str(e).lower():
        print("Error: Video file or project not found")
    elif "invalid frame" in str(e).lower():
        print("Error: Frame number is invalid")
    else:
        print(f"Error: {str(e)}")

Common Issues

Error	Cause	Solution
Invalid frame number	Negative frame number	Ensure frame_number ≥ 0
File not found	Invalid file_id	Verify the video file exists in the project
Project not video type	Non-video project	Keyframes only work with video projects
Validation error	Invalid KeyFrame structure	Check all required fields are provided

Advanced Usage

Custom Keyframe Selection Logic

Custom Keyframe Logic

def select_keyframes_with_threshold(video_length_frames, min_interval=30, max_interval=90):
    """
    Intelligently select keyframes based on video length.
    """
    keyframes = []
    
    if video_length_frames < 3000:  # Short video
        interval = min_interval
    elif video_length_frames < 10000:  # Medium video
        interval = 60
    else:  # Long video
        interval = max_interval
    
    for frame_num in range(0, video_length_frames, interval):
        keyframes.append(
            KeyFrame(frame_number=frame_num, is_manual=True, method="manual", source="manual")
        )
    
    return keyframes

# Use the custom logic
keyframes = select_keyframes_with_threshold(video_length_frames=18000)
project.add_or_update_keyframes(file_id="video_file_id", keyframes=keyframes)

Create Projects

Learn how to create video annotation projects

Retrieve Projects

Retrieve project information and file lists

Getting Started

SDK installation and initialization guide

For technical support, contact [email protected]

SDK Documentation

​Introduction

What are Keyframes?

​Video Project Setup

​Import Required Modules

​Adding or Updating Keyframes

​KeyFrame Schema

KeyFrame Parameters

​Add or Update Keyframes

​Batch Keyframe Creation

​Deleting Keyframes

​Delete Specific Keyframes

​Complete Workflow Example

End-to-End Keyframe Management

​Common Use Cases

Regular Interval Sampling

Scene Change Detection

Event-Based Selection

Adaptive Sampling

​Best Practices

Keyframe Selection Guidelines

​Optimal Keyframe Density

​Performance Considerations

​Annotation Quality

​Error Handling

Common Errors and Solutions

​Common Issues

​Advanced Usage

​Custom Keyframe Selection Logic

​Related Documentation

Create Projects

Retrieve Projects

Getting Started

Introduction

Video Project Setup

Import Required Modules

Adding or Updating Keyframes

KeyFrame Schema

Add or Update Keyframes

Batch Keyframe Creation

Deleting Keyframes

Delete Specific Keyframes

Complete Workflow Example

Common Use Cases

Best Practices

Optimal Keyframe Density

Performance Considerations

Annotation Quality

Error Handling

Common Issues

Advanced Usage

Custom Keyframe Selection Logic

Related Documentation