Input lag estimation for Wi-Fi display sinks
A source device comprising a processor and a Wi-Fi module for communicating with a sink device to stream audio/video data. The processor is configured to one of either A) identify manufacturer and model of the sink device, retrieve input lag data for the sink device from a database indexed by manufacturer and model of the sink device, and optimize encoding of the audio/video data by adjusting transmission parameters based on the input lag data; or B) generate a signal, detect the signal reproduced at the sink device, measure the input lag between generation of the signal and reproduction thereof at the sink device, and optimize encoding of the audio/video data by adjusting transmission parameters based on the input lag data.
1. A method of estimating input lag of audio/video data transmitted from a source device to a sink device, comprising:
generating an image at the source device and rendering the image on a display of the source device;
receiving, at the source device, a first input from an input device of the source device;
measuring, at the source device, a delay (d1) between the rendering the image on the display of the source device and the receiving of the first input;
transmitting the image from the source device to the sink device for reproduction on a display of the sink device;
detecting, at the source device, reproduction of the image on the display of the sink device;
receiving, at the source device, a second input from the input device;
measuring, at the source device, a delay (d2) between the detecting reproduction of the image on the display of the sink device and the receiving of the second input; and,
estimating the input lag by subtracting d1 from d2.
2. The method of claim 1 , wherein the image comprises a black square on a white background, a quick response (QR) code, or a series of colour bands.
3. The method of claim 1 , further including repeatedly generating, at the source device, the image, rendering the image on the display of the source device, and measuring, at the source device, the delay (d1), and averaging the d1's that are measured.
4. The method of claim 1 , further comprising:
generating, at the source device, a signal comprising a sound.
5. The method of claim 4 , further comprising:
transmitting, from the source device to the sink device, the signal for reproduction of the sound at the sink device;
in response to detection, at a microphone of the source device, of the sound reproduced at the sink device, measuring, at the source device, a time delay (d) between the generating of the sound and the detection of the sound reproduced at the sink device.
6. The method of claim 1 , further comprising:
generating, at the source device, a video image, the video image comprising a graphical representation of a timer and rendering the video image on the display of the source device.
7. The method of claim 6 , further comprising:
detecting, at the source device, reproduction of the video image comprising the graphical representation of the timer on the display of the sink device; and,
estimate a further input lag by measuring a delay (d) between a time indicated the video image comprising the graphical representation of the timer is rendered on the display of the source device and a time reproduction of the video image comprising the graphical representation of the timer on the display of the sink device is detected.
8. A source device comprising:
a display;
an input device;
a Wi-Fi module configured to communicate with a Wi-Fi module of a sink device;
a processor operably coupled to the input device, the display, and the Wi-Fi module, the processor configured to:
generate an image and render the image on the display;
receive a first input from the input device;
measure a delay (d1) between the rendering the image on the display and the receipt of the first input;
transmit, via the Wi-Fi module, the image to the sink device for reproduction on a display of the sink device;
detect reproduction of the image on the display of the sink device;
receive a second input from the input device;
measure delay (d2) between the detecting reproduction of the image on the display of the sink device and the receipt of the second input; and,
estimate an input lag for transmitting the image by subtracting d1 from d2.
9. The source device of claim 8 , wherein the image comprising a black square on a white background, a quick response (QR) code, or a series of colour bands.
10. The source device of claim 8 , wherein the processor is further configured to repeatedly generate the image, render the image on the display, and measure the delay (d1), and average the d1's that are measured.
11. The source device of claim 8 , wherein the processor is further configured to:
generate a signal comprising a sound.
12. The source device of claim 11 , wherein the processor is further configured to:
transmit the signal to the sink device for reproduction of the sound at the sink device; and,
in response to detection, at a microphone of the source device, of the sound reproduced at the sink device, measure a time delay (d) between the generation of the sound and the detection of the sound reproduced at the sink device.
13. The source device of claim 8 , wherein the processor is further configured to:
generate a video image, the video image comprising a graphical representation of a timer and rendering the video image on the display of the source device.
14. The source device of claim 13 , wherein the processor is further configured to:
detect reproduction of the video image comprising the graphical representation of the timer on the display of the sink device; and,
estimate a further input lag by measuring a delay (d) between a time indicated the video image comprising the graphical representation of the timer is rendered on the display of the source device and a time the video image comprising the graphical representation of the timer on the display of the sink device is detected.