iot/labs/Demo/Demo.Android/Controls/PreviewCallback.cs

using Android.Hardware;
using SkiaSharp.Views.Android;
using System;
using System.IO;

namespace Demo.Droid.Controls
{
    public class PreviewCallback : Java.Lang.Object, Camera.IPreviewCallback
    {
        private int width;
        private int height;
        private Android.Graphics.ImageFormatType previewFormat;

        public PreviewCallback(int width, int height, Android.Graphics.ImageFormatType previewFormat)
        {
            this.width = width;
            this.height = height;
            this.previewFormat = previewFormat;
        }

        public void OnPreviewFrame(byte[] data, Camera camera)
        {
            var jpegBytes = this.ConvertYuvToJpeg(data);
            using (var droidBitmap = Android.Graphics.BitmapFactory.DecodeByteArray(jpegBytes, 0, jpegBytes.Length))
            {
                using (var skBitmap = droidBitmap.ToSKBitmap())
                {
                    var base64 = Convert.ToBase64String(jpegBytes);
                }
            }
        }

        private byte[] ConvertYuvToJpeg(byte[] yuvData, int quality = 80)
        {
            byte[] result = null;
            using (var yuv = new Android.Graphics.YuvImage(yuvData, previewFormat, width, height, null))
            {
                using (var ms = new MemoryStream())
                {
                    yuv.CompressToJpeg(new Android.Graphics.Rect(0, 0, width, height), quality, ms);
                    result = ms.ToArray();
                }
            }
            return result;
        }
    }
}