Extract frames from videos

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Pull frames from video files at specified intervals for analysis, thumbnails, or training data.

Problem

You have video files and need to extract frames for:

Object detection on video content
Creating thumbnails or previews
Building training datasets
Scene analysis and classification

Solution

What’s in this recipe:

Extract frames at a fixed rate (FPS)
Extract a specific number of frames
Extract only keyframes for efficiency

You create a view with a frame_iterator that automatically extracts frames from each video. New videos are processed without extra code.

Setup

%pip install -qU pixeltable

Load videos

import pixeltable as pxt
from pixeltable.functions.video import frame_iterator

# Create a fresh directory
pxt.drop_dir('video_demo', force=True)
pxt.create_dir('video_demo')

Connected to Pixeltable database at: postgresql+psycopg://postgres:@/pixeltable?host=/Users/pjlb/.pixeltable/pgdata
Created directory ‘video_demo’.
<pixeltable.catalog.dir.Dir at 0x1695d2650>

# Create table for videos
videos = pxt.create_table('video_demo/videos', {'video': pxt.Video})

Created table ‘videos’.

# Insert a sample video
videos.insert(
    [
        {
            'video': 'https://raw.githubusercontent.com/pixeltable/pixeltable/main/docs/resources/bangkok.mp4'
        }
    ]
)

Inserting rows into `videos`: 1 rows [00:00, 212.90 rows/s]
Inserted 1 row with 0 errors.
1 row inserted, 2 values computed.

Extract frames at fixed rate

Create a view that extracts 1 frame per second:

# Extract 1 frame per second
frames = pxt.create_view(
    'video_demo/frames',
    videos,
    iterator=frame_iterator(
        videos.video,
        fps=1.0,  # 1 frame per second
    ),
)

Inserting rows into `frames`: 19 rows [00:00, 8687.65 rows/s]

# View extracted frames
frames.select(frames.frame, frames.pos).head(3)

Extract keyframes only

For faster processing, extract only keyframes (I-frames):

# Extract only keyframes (much faster for long videos)
keyframes = pxt.create_view(
    'video_demo/keyframes',
    videos,
    iterator=frame_iterator(videos.video, keyframes_only=True),
)
keyframes.select(keyframes.frame).head(3)

Inserting rows into `keyframes`: 7 rows [00:00, 3277.53 rows/s]

Explanation

Extraction options:

Only one of fps, num_frames, or keyframes_only can be specified. When to use keyframes:

Quick video scanning and thumbnails
Initial content classification
Processing very long videos

Frame metadata: Each frame includes:

frame: The extracted image
pos: Frame position in the video
pts: Presentation timestamp

Welcome to Pixeltable

Tools

Core Concepts

How-To

Problem

Solution

Setup

Load videos

Extract frames at fixed rate

Extract keyframes only

Explanation

See also

​Problem

​Solution

​Setup

​Load videos

​Extract frames at fixed rate

​Extract keyframes only

​Explanation

​See also

Problem

Solution

Setup

Load videos

Extract frames at fixed rate

Extract keyframes only

Explanation

See also