在两个iOS设备之间通过Bonjour流式传输图像 [英] streaming images over bonjour between two iOS device

问题描述

我的目标是通过Bonjour将AVCpatureInput捕获的图像从一台iOS设备流传输到另一台iOS设备.

My goal is to stream images captured by AVCpatureInput from one iOS device to another via bonjour.

这是我当前的方法:

1)从视频输入捕获帧

1) Capture frame from video input

- (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(来自 http://mobileorchard.com/tutorial-networking-and-bonjour-on-iphone/)

2) Send over TCP connection (from http://mobileorchard.com/tutorial-networking-and-bonjour-on-iphone/)

// 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要显示在接收设备的UIImageView上的图像

3) Read the data and convert it back into an image to be displayed on the receiving device's UIImageView

// 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，当连接变得不稳定时，UIImage会引发一个错误，表明它无法呈现JPEG.

However, when the connection gets choppy, UIImage throws an error that it cannot render the JPEG.

我应该如何通过wifi传递图像?

How should I pass images through wifi?

可以跳过某些帧，这是可以的，我需要一种方法来告诉UIImage跳过坏数据的批处理".

It's okay if some frames skip, I need a way to tell UIImage to skip that "batch" of bad data.

谢谢！

推荐答案

UIImage不符合NSCoding-> NSKeyedArchiver失败.

UIImage does not conform to NSCoding --> NSKeyedArchiver fails.

您必须使用UIImagePNGRepresentation()来获取图像数据.或使用UIImageJPEGRepresentation()来压缩数据.

You'll have to use UIImagePNGRepresentation() to get the data of the image. Or use UIImageJPEGRepresentation() for compressed data.

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