bytedeco/javacv

How to specify the screen for screen capturing in JavaCV

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#2,324 opened on Mar 14, 2025

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Description

On Windows, I am using the following code for screen capturing. I would like to ask how I can specify which screen to capture in a multi-screen setup.


FFmpegFrameGrabber grabber = new FFmpegFrameGrabber("desktop");
grabber.setFormat("gdigrab");
grabber.setOption("draw_mouse", "0");
grabber.setOption("offset_x", "1920");
grabber.setOption("offset_y", "0");
grabber.setOption("framerate", "45");
grabber.setOption("hwaccel", "auto");
grabber.setOption("threads", "auto");
grabber.start();

Contributor guide

Research direction
The user wants to capture a specific screen in a multi monitor setup. In gdigrab, you can specify the monitor by its index (0 for primary, 1 for first secondary, etc.) using the input format: 'desktop' plus the monitor number, e.g., 'desktop' (default primary) or 'desktop:monitor=1'. Alternatively, use offset x and offset y to shift the capture region to the desired monitor. For example, on a dual monitor setup with primary at (0,0) and secondary at (1920,0), set offset x to 1920 and offset y to 0 to capture the secondary monitor. Provide a code example and refer to FFmpeg gdigrab documentation for more details.
Tech stack
java
Domain
desktop
Issue type
Documentation
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
JavaJavaCVFFmpeg concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75