在两个iOS设备之间通过bonjour流式传输图像

我的目标是通过bonjour将AVCpatureInput从一台iOS设备捕获的图像流式传输到另一台设备.

这是我目前的方法：

1)从视频输入捕获帧

- (void)captureOutput:(AVCaptureOutput *)captureOutput 
didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer 
   fromConnection:(AVCaptureConnection *)connection 
{ 
    /*code to convert sampleBuffer into UIImage */
    NSData * imageData = UIImageJPEGRepresentation(image,1.0);
    [connection sendImage:image];
}

2)通过TCP连接发送(从http://mobileorchard.com/tutorial-networking-and-bonjour-on-iphone/开始)

// Send raw image over network
- (void)sendRawImagePacket:(UIImage *)image {
// Encode packet
NSData * imageData = UIImageJPEGRepresentation(image,1.0);

NSData * rawPacket = [NSKeyedArchiver archivedDataWithRootObject:imageData];

// Write header: length of raw packet
int packetLength = [rawPacket length];

[outgoingDataBuffer appendBytes:&packetLength length:sizeof(int)];

[outgoingDataBuffer appendData:rawPacket];

// Try to write to stream
[self writeOutgoingBufferToStream];
}

3)读取数据并将其转换回图像,以显示在接收设备的UIImageView上

// Read as many bytes from the stream as possible and try to extract meaningful packets
- (void)readFromStreamIntoIncomingBuffer {
// Temporary buffer to read data into
UInt8 buf[1024];

// Try reading while there is data
while( CFReadStreamHasBytesAvailable(readStream) ) {  
   CFIndex len = CFReadStreamRead(readStream,buf,sizeof(buf));
if ( len <= 0 ) {
  // Either stream was closed or error occurred. Close everything up and treat this as "connection terminated"
  [self close];
  [delegate connectionTerminated:self];
  return;
 }

  [incomingDataBuffer appendBytes:buf length:len];
}

// Try to extract packets from the buffer.
//
// Protocol: header + body
//  header: an integer that indicates length of the body
//  body: bytes that represent encoded NSDictionary

// We might have more than one message in the buffer - that's why we'll be reading it inside the while loop
 while( YES ) {
// Did we read the header yet?
if ( packetBodySize == -1 ) {
  // Do we have enough bytes in the buffer to read the header?
  if ( [incomingDataBuffer length] >= sizeof(int) ) {
    // extract length
    memcpy(&packetBodySize,[incomingDataBuffer bytes],sizeof(int));

    // remove that chunk from buffer
    NSRange rangeToDelete = {0,sizeof(int)};
    [incomingDataBuffer replaceBytesInRange:rangeToDelete withBytes:NULL length:0];
  }
  else {
    // We don't have enough yet. Will wait for more data.

      break;

  }
}

// We should now have the header. Time to extract the body.
if ( [incomingDataBuffer length] >= packetBodySize ) {
  // We now have enough data to extract a meaningful packet.
  NSData* raw = [NSData dataWithBytes:[incomingDataBuffer bytes] length:packetBodySize];

  // Tell our delegate about it

            NSData * imageData = [NSKeyedUnarchiver unarchiveObjectWithData:raw];

            UIImage * image = [UIImage imageWithData:imageData];
            [delegate receivedNetworkRawImage:image viaConnection:self];


  // Remove that chunk from buffer
  NSRange rangeToDelete = {0,packetBodySize};
  [incomingDataBuffer replaceBytesInRange:rangeToDelete withBytes:NULL length:0];

  // We have processed the packet. Resetting the state.
  packetBodySize = -1;
}
else {
  // Not enough data yet. Will wait.
  break;
 }
}
}

但是,当连接断电时,UIImage会抛出一个无法呈现JPEG的错误.

我应该如何通过wifi传递图像？

没关系,如果有些帧跳过,我需要一种方法告诉UIImage跳过那批“坏”数据.

谢谢！

解决方法

UIImage不符合NSCoding – > NSKeyedArchiver失败了.

您必须使用UIImagePNGRepresentation()来获取图像的数据.或者对压缩数据使用UIImageJPEGRepresentation().