我一直在做一个私人项目，想要学习如何在Windows手机上编程。在尝试使用套接字和摄像头时，我产生了一个非常好的想法 - 视频流。
但是现在我遇到了问题，Lumia 800不能够快速地处理for-loop，每7-8秒只发送一帧画面，这让我感到困惑，因为应该足够快。它看起来就像在56k调制解调器上观看色情片而没有真正的色情内容。
我也意识到一帧有317,000个像素，大约占用1MB的空间。我还发送xy坐标，所以每帧总共需要2.3MB。我正在寻找其他方法来降低数据量。如果要获得可接受的速度，则需要施展魔术来使位置和像素值变为合理的大小。因为目前要达到可接受的速度至少需要60MB/s才能获得30fps，但这是另一个问题了。
//How many pixels to send per burst (1000 seems to be the best)
const int PixelPerSend = 1000;
int bSize = 7 * PixelPerSend;
//Comunication thread UDP feed
private void EthernetComUDP() //Runs in own thread
{
//Connect to Server
clientUDP = new SocketClientUDP();
int[] ImageContent = new int[(int)cam.PreviewResolution.Height * (int)cam.PreviewResolution.Width];
byte[] PacketContent = new byte[bSize];
string Pixel,l;
while (SendingData)
{
cam.GetPreviewBufferArgb32(ImageContent);
int x = 1, y = 1, SenderCount = 0;
//In dire need of a speedup
for (int a = 0; a < ImageContent.Length; a++) //this loop
{
Pixel = Convert.ToString(ImageContent[a], 2).PadLeft(32, '0');
//A - removed to conserve bandwidth
//PacketContent[SenderCount] = Convert.ToByte(Pixel.Substring(0, 8), 2);//0
//R
PacketContent[SenderCount] = Convert.ToByte(Pixel.Substring(8, 8), 2);//8
//G
PacketContent[SenderCount + 1] = Convert.ToByte(Pixel.Substring(16, 8), 2);//16
//B
PacketContent[SenderCount + 2] = Convert.ToByte(Pixel.Substring(24, 8), 2);//24
//Coordinates
//X
l = Convert.ToString(x, 2).PadLeft(16, '0');
//X bit(1-8)
PacketContent[SenderCount + 3] = Convert.ToByte(l.Substring(0, 8), 2);
//X bit(9-16)
PacketContent[SenderCount + 4] = Convert.ToByte(l.Substring(8, 8), 2);
//Y
l = Convert.ToString(y, 2).PadLeft(16, '0');
//Y bit(1-8)
PacketContent[SenderCount + 5] = Convert.ToByte(l.Substring(0, 8), 2);
//Y bit(9-16)
PacketContent[SenderCount + 6] = Convert.ToByte(l.Substring(8, 8), 2);
x++;
if (x == cam.PreviewResolution.Width)
{
y++;
x = 1;
}
SenderCount += 7;
if (SenderCount == bSize)
{
clientUDP.Send(ConnectToIP, PORT + 1, PacketContent);
SenderCount = 0;
}
}
}
//Close on finish
clientUDP.Close();
}
我尝试简化操作，只是单独发送像素。使用以下方法：
BitConverter.GetBytes(ImageContent[a]);
我创建了一个混乱的字符串解析方法(仅为证明概念而修复)，但使用简单的BitConverter并没有使其加速太多。
所以现在我的最后一个想法是使用与MSDN库中大致相同的UDP发送套接字。
public string Send(string serverName, int portNumber, byte[] payload)
{
string response = "Operation Timeout";
// We are re-using the _socket object that was initialized in the Connect method
if (_socket != null)
{
// Create SocketAsyncEventArgs context object
SocketAsyncEventArgs socketEventArg = new SocketAsyncEventArgs();
// Set properties on context object
socketEventArg.RemoteEndPoint = new DnsEndPoint(serverName, portNumber);
// Inline event handler for the Completed event.
// Note: This event handler was implemented inline in order to make this method self-contained.
socketEventArg.Completed += new EventHandler<SocketAsyncEventArgs>(delegate(object s, SocketAsyncEventArgs e)
{
response = e.SocketError.ToString();
// Unblock the UI thread
_clientDone.Set();
});
socketEventArg.SetBuffer(payload, 0, payload.Length);
// Sets the state of the event to nonsignaled, causing threads to block
_clientDone.Reset();
// Make an asynchronous Send request over the socket
_socket.SendToAsync(socketEventArg);
// Block the UI thread for a maximum of TIMEOUT_MILLISECONDS milliseconds.
// If no response comes back within this time then proceed
_clientDone.WaitOne(TIMEOUT_MILLISECONDS);
}
else
{
response = "Socket is not initialized";
}
return response;
}
总的来说，我已经得出了3个解决方案：
接受失败（但这不可能发生，所以让我们看看第二个方案）
减少发送的数据量（会破坏质量，640x480足够小了）
找到明显的问题（谷歌和朋友们都没有好主意，所以我来了）