Screen Capture Blocking

Screen capture blocking prevents on-device recording or screenshots of protected video. In native Android apps FLAG_SECURE blanks captured frames, and iOS can detect and blank capture; hardware DRM reinforces this. On desktop web there is no reliable block, so capture is deterred with watermarking rather than prevented.

What is Screen Capture Blocking?

Screen capture blocking prevents on-device screen recording or screenshots of protected video. How well it works depends entirely on the platform.

Platform by Platform

  • Android apps: The FLAG_SECURE window flag causes screenshots and recordings to capture a black frame; hardware DRM reinforces it.
  • iOS apps: The OS can signal screen capture and recording so the app can blank or pause protected content.
  • Desktop web: Browsers expose no reliable API to block recording, so it cannot be prevented, only deterred.

The Web Reality

Because desktop browsers cannot block capture, any platform claiming to stop screen recording in the browser is overclaiming. The honest and effective approach there is dynamic watermarking, which makes recordings carry the viewer's identity.

For Platform Owners

Use FLAG_SECURE and iOS capture handling in your native apps, and rely on visible watermarking on the web. Combining app-level blocking with everywhere-watermarking covers the realistic range of what is possible.

See Also: Screen RecordingDynamic WatermarkingHardware-Backed DRMTrusted Execution Environment (TEE)