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In search for the secret ingredient to instant touch and audio response

05 Apr 2016

Google released a new tool for measuring touch and audio latency on Android and Chrome OS devices: the WALT Latency Timer

Patience is a virtue. Well, not in the case when you are tapping your smartphone and every millisecond is a torture. Today’s modern app user expects his phone to respond instantly to his touch and voice command: the more immediate the response, the more he feels directly connected to the device.  That is why Google has been hard at work to prevent consumers from suffering “lag time” and keep on savoring their mobile experience. The company has announced its latest open source tool – the WALT Latency Timer which measures touch and audio latency.


Latency is essentially the time between tapping on or giving a voice command to your smartphone and the moment when the device actually responds. The total time for a tap response includes the processing delay of the touch-sensing hardware and driver, the application delay, and the display and graphics output delay. For a voice command, there is time spent on sampling the input audio, the application, and in audio output. Sometimes we have a mixture of these (for example, a piano app would include touch input and audio output). So by reducing latency, Google is able to deliver a much faster and smoother experience for the end-user.


The WALT Latency Timer is meant to be used by developers and companies looking to improve the response time of their apps through touch or audio input. The tool will help measure how fast an app processes a tap on Android and feeds back the intended response to the device. A noteworthy upgrade in WALT (a descendant of QuickStep) is that it synchronizes an external hardware clock with the Android device or Chromebook to within a millisecond. This allows it to measure input and output latencies separately as opposed to measuring a round-trip latency.


While the code of WALT is now available on GitHub, it’s important to note that there’s some hardware that goes into the testing. According to Google’s post on the Android Developers Blog, you can build their own device for under $50 and with a little bit of engineering skills under your sleeve. Any developer, pro or not, can start tinkering on the hardware and contribute to the improvement of latency times for touch and voice input. After all, the whole point of open source is to foster progress and innovation. Google hopes that having readily accessible tools will help the industry make our devices even more efficient and detachable from us.