Post-Processing

Overview

The post-processor is a Rust native module that handles video encoding and effects. It runs automatically when you call closeAndSave().

What It Does

1. Zoom interpolation - Smoothly transitions between captured zoom points
2. Cursor overlay - Renders mouse position and clicks
3. Video encoding - Outputs H.264 MP4 with configurable quality

Pipeline

Raw Webm (Playwright)
    ↓
Zoom + Mouse Processing (Rust)
    ↓
FFmpeg Encoding
    ↓
Final MP4

Configuration

The pipeline accepts these parameters:

Parameter	Type	Description
videoPath	string	Input video file
zoomLog	ZoomLogEntry[]	Zoom level timeline
mouseLog	MouseLogEntry[]	Mouse position timeline
crf	number?	Encoder quality (0-63, lower = better, default 4)
width	number	Output width
height	number	Output height
fps	number	Output frame rate
ffmpegPath	string?	Custom FFmpeg binary path

Custom FFmpeg

By default, the bundled FFmpeg binary is used. To use a custom one:

const recorder = new Recorder("./results");
recorder.setFfmpegPath("/usr/local/bin/ffmpeg");