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