gerrit-public.fairphone.software / platform / external / walt / 32cdbc5dc02735c3c6f41f8a325f457ccd124c8f
| commit | 32cdbc5dc02735c3c6f41f8a325f457ccd124c8f | [log] [tgz] |
|---|---|---|
| author | Android Build Role Account android-build-prod <android-build-team-robot@google.com> | Sat Feb 22 03:37:20 2020 +0000 |
| committer | Android Build Role Account android-build-prod <android-build-team-robot@google.com> | Sat Feb 22 03:37:20 2020 +0000 |
| tree | 78b9321cf789ee70298ed909e16956d1603755a9 | |
| parent | 0465ba01788a9537b03d150fdf67fc660f07b837 [diff] | |
| parent | 6e3ca9c2d4a6ed9f71a784280a4ff1694b2141d3 [diff] |
Snap for 6227608 from 6e3ca9c2d4a6ed9f71a784280a4ff1694b2141d3 to r-keystone-qcom-release Change-Id: Ie44834df770696ec2e961dd547a84bc2e4975e88
tree: 78b9321cf789ee70298ed909e16956d1603755a9
- android/
- arduino/
- docs/
- hardware/
- ios/
- pywalt/
- server/
- AUTHORS
- CONTRIBUTING.md
- CONTRIBUTORS
- LICENSE
- MODULE_LICENSE_APACHE2
- NOTICE
- OWNERS
- README.google
- README.md
README.md
WALT Latency Timer
DISCLAIMER: This is not an official Google product.
- Post about WALT on Android Developers Blog
- Instructional videos showing how to use WALT
- Detailed usage instructions
- Mailing list - walt-discuss
- Low-traffic mailing list for major announcements walt-announce
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.
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.