# video-use Event Listeners: Understanding the API Availability

> Discover that video-use lacks an event-listener API. Understand its direct function call approach instead of event-driven architecture in this technical explanation.

- Repository: [Browser Use/video-use](https://github.com/browser-use/video-use)
- Tags: api-reference
- Published: 2026-07-10

---

**video-use does not expose any event-listener API; it is a pure-Python utility library that operates through direct function calls rather than event-driven architecture.**

The browser-use/video-use repository provides a collection of procedural helpers for video processing tasks such as frame extraction, audio envelope calculation, and timeline visualization. While developers familiar with HTML5 media players might expect event-listener patterns for handling playback events like `play` or `pause`, the library follows a fundamentally different approach that requires direct function invocation.

## Why video-use Does Not Implement Event Listeners

According to the browser-use/video-use source code, the repository is designed as a pure-Python utility collection rather than an interactive media player. All core functionality lives in procedural helper modules that execute immediately when called, rather than waiting for runtime events.

### Core Architecture: Procedural Python Functions

The library's functionality resides entirely in Python modules such as [`helpers/timeline_view.py`](https://github.com/browser-use/video-use/blob/main/helpers/timeline_view.py), [`helpers/render.py`](https://github.com/browser-use/video-use/blob/main/helpers/render.py), and [`helpers/transcribe.py`](https://github.com/browser-use/video-use/blob/main/helpers/transcribe.py). None of these modules define or register listeners for HTML-video events like `play`, `pause`, or `timeupdate`. Instead, users interact with the library by importing these modules and calling functions directly with specific parameters.

### No JavaScript Front-End Component

Because video-use does not ship a JavaScript front-end component, there is no `addEventListener` method or similar registration function available. The library operates server-side or inPython scripts, processing video files through computational routines rather than responding to user interaction events in a browser environment.

## Audio Events vs. Event Listeners

The only "event-like" concepts in the codebase are **audio events** that appear as structured data entries within transcripts. These are distinct from runtime event listeners.

### Transcript Data Structure

In [`helpers/transcribe.py`](https://github.com/browser-use/video-use/blob/main/helpers/transcribe.py), audio events appear as data payloads with a specific type field (e.g., `"type": "audio_event"`). These entries represent segments of audio activity detected during transcription processing, stored as JSON data for later analysis. They are **data classifications**, not runtime callbacks or listeners that trigger code execution.

## Working with video-use: Direct Function Calls

Since video-use event listeners do not exist, you interact with the library through explicit function calls. Below are the primary patterns for utilizing the core API.

### Rendering Timeline Visualizations

To generate a composite timeline image showing video frames and transcript overlays, call `render_timeline()` directly from [`helpers/timeline_view.py`](https://github.com/browser-use/video-use/blob/main/helpers/timeline_view.py):

```python
from helpers.timeline_view import render_timeline
from pathlib import Path

render_timeline(
    video=Path("my_video.mp4"),
    start=12.5,
    end=17.0,
    out_path=Path("timeline.png"),
    n_frames=8,
    transcript=Path("my_transcript.json"),
)

```

### Extracting Video Frames

To extract specific frames from a video segment, use the `extract_frames()` function:

```python
from helpers.timeline_view import extract_frames
from pathlib import Path

frames = extract_frames(
    video=Path("my_video.mp4"),
    start=0,
    end=10,
    n=5,
    dest_dir=Path("tmp_frames")
)
print(frames)   # → list of Path objects for the extracted JPEGs

```

## Key Source Files

The following modules collectively provide video-use functionality, but none expose a runtime event-listener interface:

- **[`helpers/timeline_view.py`](https://github.com/browser-use/video-use/blob/main/helpers/timeline_view.py)** – Core API for frame extraction, audio envelope computation, transcript overlay, and composite PNG rendering
- **[`helpers/render.py`](https://github.com/browser-use/video-use/blob/main/helpers/render.py)** – Low-level rendering utilities including font handling, color management, and image compositing
- **[`helpers/transcribe.py`](https://github.com/browser-use/video-use/blob/main/helpers/transcribe.py)** – Transcript parsing and audio-event tagging functionality
- **[`helpers/pack_transcripts.py`](https://github.com/browser-use/video-use/blob/main/helpers/pack_transcripts.py)** – Transcript packaging and silence gap computation

## Summary

- **video-use does not expose event listeners**; it is a procedural Python library, not an event-driven framework
- All functionality requires **direct function calls** to methods like `render_timeline()` and `extract_frames()`
- **Audio events** in [`helpers/transcribe.py`](https://github.com/browser-use/video-use/blob/main/helpers/transcribe.py) are data payloads (e.g., `"type": "audio_event"`), not runtime callbacks
- The library lacks a JavaScript front-end, so there is no `addEventListener` equivalent
- Users seeking reactive media-player behavior must implement their own front-end event handling and call video-use functions when specific events fire

## Frequently Asked Questions

### Does video-use support HTML5 video events like play and pause?

No. video-use does not include a JavaScript runtime or HTML5 video player component. It is a server-side Python library for processing video files programmatically. If you need to react to `play` or `pause` events, you must implement that logic in your own front-end application and then invoke the appropriate video-use Python functions.

### What are audio events in the video-use transcript files?

Audio events are data annotations stored in transcript JSON files processed by [`helpers/transcribe.py`](https://github.com/browser-use/video-use/blob/main/helpers/transcribe.py). They appear as dictionary entries with fields like `"type": "audio_event"` to mark segments of detected audio activity. These are static data labels used for timeline visualization, not dynamic event listeners that execute code.

### How do I trigger actions when video processing completes?

Since video-use lacks an event system, you trigger actions by calling functions sequentially in your Python script. For example, call `extract_frames()` followed by `render_timeline()` in the same script execution flow. The functions return results immediately (such as file paths or processed data) that you can pass to subsequent operations.

### Can I add custom event listeners to the video-use source code?

While you could theoretically wrap video-use functions in your own event-driven architecture, the library itself provides no hooks or extension points for event registration. The source code in [`helpers/timeline_view.py`](https://github.com/browser-use/video-use/blob/main/helpers/timeline_view.py) and related modules uses straightforward procedural programming. Any event-listener functionality would require building a custom wrapper or middleware layer on top of the existing function calls.