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gerrit-public.fairphone.software / platform / external / walt / 0301aa68662fd0180307a3d7f34ce229e05012da
commit0301aa68662fd0180307a3d7f34ce229e05012da[log] [tgz]
authorTai Kuo <taikuo@google.com>Thu Jul 30 19:16:42 2020 +0000
committerAutomerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>Thu Jul 30 19:16:42 2020 +0000
tree27044bca824087616b2e2c3641c660d5ed082e9f
parent451bd188f9d83377f15c7c8c8a5ec8b5646095ad [diff]
parent3982a6787b6168afc61332ed149721e6cfbad044 [diff]
[automerger skipped] Deprecate OpenSL ES for Android as of API level 30 (R) am: 484fb8a77d am: 56db2d6fa9 -s ours am: ff4f624a41 -s ours am: af43d4b4c1 -s ours am: 3982a6787b -s ours

am skip reason: Change-Id Ie0a317debd07230d344218c5874f3060dc3ab85f with SHA-1 cf1f411f8c is in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/walt/+/11926619

Change-Id: I26df1d36fbb98dac97280e9f60542345ee095325
tree: 27044bca824087616b2e2c3641c660d5ed082e9f
  1. android/
  2. arduino/
  3. docs/
  4. hardware/
  5. ios/
  6. pywalt/
  7. server/
  8. AUTHORS
  9. CONTRIBUTING.md
  10. CONTRIBUTORS
  11. LICENSE
  12. METADATA
  13. MODULE_LICENSE_APACHE2
  14. OWNERS
  15. README.google
  16. README.md
README.md

WALT Latency Timer

DISCLAIMER: This is not an official Google product.

WALT is designed to measure the latency of physical sensors and outputs on phones and computers. It can currently perform the following measurements:

  • Tap latency - time from the moment a finger-like probe touches down (or up) on the screen until the kernel timestamps an ACTION_DOWN (or ACTION_UP) event. This physical contact with the screen is timed using an accelerometer mounted on the probe.
  • Drag latency (scroll).
  • Screen draw latency - using a photodiode that detects whether the screen is black or white.
  • Audio output and microphone latencies.
  • MIDI input and output latencies

The WALT app for Android can be installed from Google Play or downloaded in the releases section; the iOS app must be built from source.

WALT photo

Notes

  • Hardware build instructions can be found in this repository under hardware/.
  • Clock synchronization details are described here.
  • The Android/iOS device and Teensy clocks have a tendency to diverge due to differing clock frequencies. This means they will go out of sync after several minutes. The workaround is to use the app to re-sync the clocks. Some, but not all tests in the app will sync the clocks when starting a measurement.
  • Python code used to communicate with WALT from Linux and ChromeOS can be found here.