好的。经过几天与许多捕获方法和色彩量化师的斗争后,我终于找到了解决方案。现在,我可以以10〜14 FPS的速度发送整个桌面图像,并以20〜30 FPS的速度改变桌面区域。
在代码中我使用rcravens的类来捕获屏幕和屏幕的变化。然后我把这幅图像剪成10张。在此之后,我带了一些小片,并使用Octree Color Quantizier解释here使它们成为256色,这要归功于@Dai,他指出了我的发展方向。减色后,我将每一块转换为一个字节数组,并使用LZ4.Net库进行压缩。
下面是代码:
int all_count = 0;
Bitmap _desktop = null;
Bitmap _merged_bitmap = new Bitmap(1600, 900);
int _height_part_ = 0;
int _total_rows = 10;
Bitmap[] crops = null;
Bitmap[] _new_crops = null;
Stopwatch sw = new Stopwatch();
int _desktop_height = 0;
int _desktop_width = 0;
ImageManipulation.OctreeQuantizer _q ;
RLC.RemoteDesktop.ScreenCapture cap = new RLC.RemoteDesktop.ScreenCapture();
private void CaptureAndSend()
{
sw.Restart();
//cap = new RLC.RemoteDesktop.ScreenCapture();
int _left = -1, _top = -1; //Changed regions
_desktop = cap.Screen(out _left, out _top); //Capture desktop or changed region of it
if (_desktop == null) return; //if nothing has changed since last capture skip everything
_desktop_height = _desktop.Height;
_desktop_width = _desktop.Width;
// If very small part has changed since last capture skip everything
if (_desktop_height < 10 || _desktop_width < 10) return;
TotalRows(_total_rows); // Calculate the total number of rows
crops = new Bitmap[_total_rows]; // Cropped pieces of image
_new_crops = new Bitmap[_total_rows];
for (int i = 0; i < _total_rows - 1; i++) //Take whole image and split it into smaller images
crops[i] = CropRow(i);
crops[_total_rows - 1] = CropLastRow(_total_rows - 1);
Parallel.For(0, _total_rows, i =>
{
ImageManipulation.OctreeQuantizer _q = new ImageManipulation.OctreeQuantizer(255, 4); // Initialize Octree
_new_crops[i] = _q.Quantize(crops[i]);
using (MemoryStream ms=new MemoryStream())
{
_new_crops[i].Save(ms, ImageFormat.Png);
//Install-Package LZ4.net
//Compress each part and send them over network
byte[] data = Lz4Net.Lz4.CompressBytes(ms.ToArray(), Lz4Net.Lz4Mode.HighCompression);
all_count += data.Length; //Just to check the final size of image
}
});
Console.WriteLine(String.Format("{0:0.0} FPS , {1} seconds , size {2} kb", 1.0/sw.Elapsed.TotalSeconds, sw.Elapsed.TotalSeconds.ToString(), all_count/1024));
all_count = 0;
}
private void TotalRows(int parts)
{
_height_part_ = _desktop_height/parts;
}
private Bitmap CropRow(int row)
{
return Crop(_desktop, new Rectangle(0, row * _height_part_, _desktop_width, _height_part_));
}
private Bitmap CropLastRow(int row)
{
return Crop(_desktop, new Rectangle(0, row * _height_part_, _desktop_width, _desktop_height - (row * _height_part_)));
}
[DllImport("msvcrt.dll", CallingConvention = CallingConvention.Cdecl)]
private unsafe static extern int memcpy(byte* dest, byte* src, long count);
private unsafe Bitmap Crop(Bitmap srcImg, Rectangle rectangle)
{
if ((srcImg.Width == rectangle.Width) && (srcImg.Height == rectangle.Height))
return srcImg;
var srcImgBitmapData = srcImg.LockBits(new Rectangle(0, 0, srcImg.Width, srcImg.Height), ImageLockMode.ReadOnly, srcImg.PixelFormat);
var bpp = srcImgBitmapData.Stride/srcImgBitmapData.Width; // 3 or 4
var srcPtr = (byte*)srcImgBitmapData.Scan0.ToPointer() + rectangle.Y * srcImgBitmapData.Stride + rectangle.X * bpp;
var srcStride = srcImgBitmapData.Stride;
var dstImg = new Bitmap(rectangle.Width, rectangle.Height, srcImg.PixelFormat);
var dstImgBitmapData = dstImg.LockBits(new Rectangle(0, 0, dstImg.Width, dstImg.Height), ImageLockMode.WriteOnly, dstImg.PixelFormat);
var dstPtr = (byte*)dstImgBitmapData.Scan0.ToPointer();
var dstStride = dstImgBitmapData.Stride;
for (int y = 0; y < rectangle.Height; y++)
{
memcpy(dstPtr, srcPtr, dstStride);
srcPtr += srcStride;
dstPtr += dstStride;
}
srcImg.UnlockBits(srcImgBitmapData);
dstImg.UnlockBits(dstImgBitmapData);
return dstImg;
}
我知道,我的代码是不是记忆效率。如果有人能帮我优化这个代码,我会很感激。 再次感谢我的朋友A.阿布拉莫夫,戴,HansPassant,TaW等人。
无需将图像转换为256色,只需将截图保存为24位PNG或JPEG图像,即可获得更清晰可读的内容,而且尺寸仅为几百KiB。 – Dai
VNC为帧使用JPEG压缩,Windows中的远程桌面使用不同的技术,以协议复杂度为代价,涉及更多的巫术。 TeamViewer使用他们自己的协议,采用一些黑客技术,如颜色下采样,但也包括线倍增。现在RDP采用JPEG压缩技术处理快速移动的场景,但其拼贴方式不起作用。 – Dai
谢谢,但最终所有这些应用程序都有256色选项,并且在慢速连接中它们会自动选择此选项。 256色图像大约70-80 KiB,质量合理。我正在寻找能够在1/15秒内制作256色图像的最快方法。 – miladrasooli