gerrit-public.fairphone.software / platform / external / walt / 451bd188f9d83377f15c7c8c8a5ec8b5646095ad
| commit | 451bd188f9d83377f15c7c8c8a5ec8b5646095ad | [log] [tgz] |
|---|---|---|
| author | Bob Badour <bbadour@google.com> | Wed Apr 29 16:22:37 2020 +0000 |
| committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | Wed Apr 29 16:22:37 2020 +0000 |
| tree | 27044bca824087616b2e2c3641c660d5ed082e9f | |
| parent | 44164c9eec810a729381dc22f3c68025b8e43ac8 [diff] | |
| parent | b1feb8fd598b60a7d7707421ce391b273fd55bd1 [diff] |
Add METADATA to walt: Apache2=NOTICE am: 58b0ab1a62 am: b45616374a am: 152923487d am: b1feb8fd59 Change-Id: I66ed4c2f183180149d024b014241d7d435feaa64
tree: 27044bca824087616b2e2c3641c660d5ed082e9f
- android/
- arduino/
- docs/
- hardware/
- ios/
- pywalt/
- server/
- AUTHORS
- CONTRIBUTING.md
- CONTRIBUTORS
- LICENSE
- METADATA
- MODULE_LICENSE_APACHE2
- 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.