Перейти к содержимому

Исходный код вики Camera Preview (Android)

Редактировал(а) Alexandr Fokin 2022/08/04 20:45
Последние авторы
1 Получение трансляции изображения с камеры устройства Android, с конвертацией кадров в JPEG.
2
3
4 {{code language="c#"}}
5 using Android.Hardware;
6 using Android.Hardware.Camera2;
7 using Android.Views;
8 using YuvImage = Android.Graphics.YuvImage;
9
10 internal class AndroidCameraProvider
11 {
12 public VideoCaptureContainer CaptureVideo(
13 Action<byte[]> onFrameReceive
14 )
15 {
16 var capture = new VideoCaptureContainer(onFrameReceive);
17 return capture;
18 }
19
20
21 #region Types
22
23 public class VideoCaptureContainer
24 : CameraDal.IVideoCaptureContainer
25 {
26 //private readonly Action<byte[]> OnFrameReceive;
27 private readonly Camera Camera;
28 private readonly Handler Handler;
29
30
31 internal VideoCaptureContainer(
32 Action<byte[]> onFrameReceive
33 )
34 {
35 if (Android.OS.Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.Lollipop)
36 {
37 throw new NotSupportedException();
38 }
39
40
41 var numberOfCameras = Camera.NumberOfCameras;
42 var info = Enumerable.Range(0, numberOfCameras)
43 .Select(
44 e =>
45 {
46 var info = new CameraInfo();
47 Camera.GetCameraInfo(e, info);
48 return (Id: e, Info: info);
49 }
50 )
51 .ToDictionary(e => e.Id, e => e);
52
53 var cameraId = info.Values
54 .First(e => e.Info.Facing == CameraFacing.Back);
55 //OnFrameReceive = onFrameReceive;
56
57 Camera = Camera.Open(cameraId.Id);
58 var cameraParams = Camera.GetParameters();
59
60 //Format
61 var defaultFormat = cameraParams.PreviewFormat;
62 var supportedFormats = cameraParams.SupportedPreviewFormats
63 .Select(e => (Android.Graphics.ImageFormatType)(int)e)
64 .ToHashSet();
65 if (!supportedFormats.Contains(Android.Graphics.ImageFormatType.Nv21))
66 {
67 throw new Exception($"Application Format not supported on device. {Android.Graphics.ImageFormatType.Nv21}");
68 }
69 cameraParams.PreviewFormat = Android.Graphics.ImageFormatType.Nv21;
70
71 //FrameRate
72 var defaultRate = cameraParams.PreviewFrameRate;
73 var supportedRates = cameraParams.SupportedPreviewFrameRates
74 .Select(e => (int)e)
75 .ToHashSet();
76 //cameraParams.PreviewFrameRate = supportedRates.Min();
77 //cameraParams.PreviewFrameRate = 5;
78
79 //Size
80 var defaultSize = cameraParams.PreviewSize;
81
82 Handler = new Handler(
83 size: (Width: defaultSize.Width, Height: defaultSize.Height),
84 sourceFormat: cameraParams.PreviewFormat,
85 onReceive: onFrameReceive
86 );
87
88 Camera.SetPreviewCallback(Handler);
89 Camera.SetParameters(cameraParams);
90
91 Camera.StartPreview();
92 }
93
94 #region Dispose
95
96 private bool disposed = false;
97
98 // реализация интерфейса IDisposable.
99 public void Dispose()
100 {
101 Dispose(true);
102 // подавляем финализацию
103 GC.SuppressFinalize(this);
104 }
105
106 protected void Dispose(bool disposing)
107 {
108 if (!disposed)
109 {
110 if (disposing)
111 {
112 // Освобождаем управляемые ресурсы
113 }
114 // освобождаем неуправляемые объекты
115 //Handler.OnReceive -= OnFrameReceive;
116
117 Camera.StopPreview();
118 //Camera.Release();
119
120 Camera.Dispose();
121 //Handler.Dispose();
122
123 disposed = true;
124 }
125 }
126
127 // Деструктор
128 ~VideoCaptureContainer()
129 {
130 Dispose(false);
131 }
132
133 #endregion
134 }
135
136 private class Handler
137 : Java.Lang.Object,
138 Camera.IPreviewCallback
139 {
140 private readonly Rect rectangle;
141 private readonly Android.Graphics.ImageFormatType SourceFormat;
142 private readonly Action<byte[]> OnReceive;
143
144
145 public Handler(
146 (int Width, int Height) size,
147 Android.Graphics.ImageFormatType sourceFormat,
148 Action<byte[]> onReceive
149 )
150 {
151 rectangle = new Rect()
152 {
153 Bottom = size.Height,
154 Top = 0,
155 Left = 0,
156 Right = size.Width
157 };
158 SourceFormat = sourceFormat;
159 OnReceive = onReceive;
160 }
161
162
163 public void OnPreviewFrame(
164 byte[] data,
165 Camera camera
166 )
167 {
168 if (OnReceive == null)
169 {
170 return;
171 }
172
173 //Конвертация в нужный формат
174 YuvImage image = new YuvImage(
175 yuv: data,
176 format: SourceFormat,
177 width: (int)rectangle.Right,
178 height: (int)rectangle.Bottom,
179 strides: null
180 );
181 using (var stream = new MemoryStream())
182 {
183 image.CompressToJpeg(rectangle, 100, stream);
184 data = stream.ToArray();
185 }
186
187 OnReceive(data);
188 }
189 }
190
191 #endregion
192 }
193 {{/code}}
194
195 ----
196
197 [[Камера>>Разработка.JVM.Java.Frameworks and Apps.Android.Механизмы.Камера.WebHome]]
198
199 How get permission for camera in android.(Specifically Marshmallow)
200 [[https:~~/~~/stackoverflow.com/questions/38552144/how-get-permission-for-camera-in-android-specifically-marshmallow>>https://stackoverflow.com/questions/38552144/how-get-permission-for-camera-in-android-specifically-marshmallow]]
201
202 What is the image format in the Preview Screen when Camera is enable
203 [[https:~~/~~/stackoverflow.com/questions/23557520/what-is-the-image-format-in-the-preview-screen-when-camera-is-enable>>https://stackoverflow.com/questions/23557520/what-is-the-image-format-in-the-preview-screen-when-camera-is-enable]]
204
205 Android: How to save a preview frame as jpeg image?
206 [[https:~~/~~/stackoverflow.com/questions/1032258/android-how-to-save-a-preview-frame-as-jpeg-image>>https://stackoverflow.com/questions/1032258/android-how-to-save-a-preview-frame-as-jpeg-image]]
207
208 jamesathey/FastAndroidCamera
209 [[https:~~/~~/github.com/jamesathey/FastAndroidCamera>>https://github.com/jamesathey/FastAndroidCamera]]
210
211 How To Display A Stream From The Camera Using A TextureView In Xamarin Android App Using Visual Studio 2015
212 [[https:~~/~~/www.c-sharpcorner.com/article/how-to-display-a-stream-from-the-camera-using-a-textureview-in-xamarin-android-a/>>https://www.c-sharpcorner.com/article/how-to-display-a-stream-from-the-camera-using-a-textureview-in-xamarin-android-a/]]