why my saved video length 15s only, flush_if_second is config 120s or more time

[maomj200811]

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To Reproduce
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4. See error

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Server (please complete the following information):

• moonfire-nvr --version
• Attach a log file. Run with the RUST_BACKTRACE=1 environment variable set if possible.

Camera (please complete the following information):

• Camera manufacturer and model: [e.g. Reolink RLC-410]
• Firmware version: [e.g. V2.0.0.1215_16091800]

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

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• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
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[scottlamb]

I suspect this is the same root cause as #300. But there's no information here; the screenshot is not helpful. The other stuff in the issue template such as logs and details of the cameras being recorded are really needed to understand what's going on.