Runtime And Limits

Runtime requirements#

The current implementation expects:

• Node.js 24.12.0+
• ffmpeg on PATH

Chromium is installed automatically when Playwright does not find a local binary.

Browser behavior#

Rollberry launches headless Chromium through Playwright.

For localhost-style targets, the browser context also tolerates HTTPS certificate issues so local preview servers remain recordable.

Capture defaults#

Current defaults are:

• output: ./rollberry.mp4
• viewport: 1440x900
• fps: 60
• duration: auto
• motion: ease-in-out-sine
• timeout: 30000
• wait condition: load
• page gap: 0

Auto duration rules#

For normal capture, duration: "auto" is derived from scroll distance at roughly 800px per second and clamped between:

• minimum 4s
• maximum 40s

Timeline scroll segments in project renders use a separate auto-duration rule:

• roughly 1400px per second
• minimum 0.6s
• maximum 12s

Important limits#

Current implementation limits include:

• maximum FPS: 120
• maximum measured scroll height: 30000px
• maximum total frames in a run: 36000

If a page exceeds the measured scroll height cap, Rollberry records a truncation warning in the manifest.

Localhost behavior#

When the target host is local, Rollberry retries transient connection failures such as ECONNREFUSED during navigation until the timeout budget is exhausted.

Configuration surface#

Most behavior is configured through:

• CLI flags for capture
• project JSON fields for render

The current codebase does not expose a separate environment-variable-based configuration layer for core capture settings.