USB Stick Writing Fix (Configurable FPS)

[jayalberts]

Evan to add suggestion

Current Issue

• Plugging in USB:
  • Camera FPS: 0-4fps
  • USB Stick: 0-2fps
• Based on USB Stick Write Speed:
  • HDC production: 2 fps
  • other, lower-end memory: 0 fps sometimes

Acceptance Criteria

• Camera reaches 10fps
  • Essentially, the same as the HDC without USB
• Without Plug:
  • 10fps on the Camera
• With Plug:
  • Camera FPS: 10
  • USB FPS: "Decent FPS" Range
    • Minimum 5
    • And more if possible
  • We at least want an improvement over the current 1-2 fps

Additional Notes

• We use timestamps to determine what XX:SS the frame was written
• We can use SSH (ls -wcl to count the image delta over time)

[evanmoss]

@HariHive Here is a simple approach to reduce write throughput to USB by 50%

bool skippedLastFrameForUSB = false;

if (!skippedLastFrameForUSB) {
  skippedLastFrameForUSB = true;
} else {
  // do write to usb
  // ...

  // reset  marker
  skippedLastFrameForUSB = false;
}

[jayalberts]

got build file yesterday from Alexei, started testing.

try to do USB 5 FPS and hivemapping 10 FPS? See if it will work.

[jayalberts]

dropping every other image didn't help with FPS (~2). Tried every 5th and FPS was closer to 10.

Writing speed of USB matter. Validate with JT's USB.

Next step: more testing and validate with metrics.

[jayalberts]

there was big regression with this so it got pulled out for 3.7. We will revisit for next iteration. Requires another round of validation.

[jayalberts]

masaya has test written for this

[jayalberts]

archive this as duplicate of https://github.com/Hivemapper/camera_bridge/issues/9