README
1This directory contains sample code to test the use of virtual
2displays created over an Android Open Accessories Protocol link.
3
4--- DESCRIPTION ---
5
6There are two applications with two distinct roles: a sink
7and a source.
8
91. Sink Application
10
11The role of the sink is to emulate an external display that happens
12to be connected using the USB accessory protocol. Think of it as
13a monitor or video dock that the user will want to plug a phone into.
14
15The sink application uses the UsbDevice APIs to receive connections
16from the source device over USB. The sink acts as a USB host
17in this arrangement and will provide power to the source.
18
19The sink application decodes encoded video from the source and
20displays it in a SurfaceView. The sink also injects passes touch
21events to the source over USB HID.
22
232. Source Application
24
25The role of the source is to present some content onto an external
26display that happens to be attached over USB. This is the typical
27role that a phone or tablet might have when the user is trying to
28play content to an external monitor.
29
30The source application uses the UsbAccessory APIs to connect
31to the sink device over USB. The source acts as a USB peripheral
32in this arrangement and will receive power from the sink.
33
34The source application uses the DisplayManager APIs to create
35a private virtual display which passes the framebuffer through
36an encoder and streams the output to the sink over USB. Then
37the application opens a Presentation on the new virtual display
38and shows a silly cube animation.
39
40--- USAGE ---
41
42These applications should be installed on two separate Android
43devices which are then connected using a USB OTG cable.
44Remember that the sink device is functioning as the USB host
45so the USB OTG cable should be plugged directly into it.
46
47When connected, the applications should automatically launch
48on each device. The source will then begin to project display
49contents to the sink.
50
51