socket 实现实时视频聊天
视频聊天从摄像头中取得缓冲数据，转换成NSData，通过网络发送，接收端取得NSData后把NSData转换成图像，双方不停的收发数据，播放图像，就形成了视频聊天。
首先创建视频输入输出：
NSError *error = nil;
// Setup the video input
AVCaptureDevice *videoDevice = [self getFrontCamera];//[AVCaptureDevice defaultDeviceWithMediaType: AVMediaTypeVideo];
// Create a device input with the device and add it to the session.
AVCaptureDeviceInput *videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:&error];
// Setup the video output
_videoOutput = [[AVCaptureVideoDataOutput alloc] init];
_videoOutput.alwaysDiscardsLateVideoFrames = NO;
_videoOutput.videoSettings =
[NSDictionary dictionaryWithObject:
[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey];
// Create the session
_capSession = [[AVCaptureSession alloc] init];
[_capSession addInput:videoInput];
//[_capSession addInput:audioInput];
[_capSession addOutput:_videoOutput];
//[_capSession addOutput:_audioOutput];
_capSession.sessionPreset = AVCaptureSessionPresetLow;
// Setup the queue
dispatch_queue_t queue = dispatch_queue_create("MyQueue", NULL);
[_videoOutput setSampleBufferDelegate:self queue:queue];
[_audioOutput setSampleBufferDelegate:self queue:queue];
dispatch_release(queue);
[_capSession startRunning];通过AVCaptureVideoDataOutputSampleBufferDelegate 代理 取得摄像头数据
#pragma mark AVCaptureSession delegate
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer
fromConnection:(AVCaptureConnection *)connection
{
NSData *data = [NSData dataWithBytes:&sampleBuffer length:malloc_size(sampleBuffer)];
[self recieveVideoFromData:data];
}收到数据后转换成图像
- (void)recieveVideoFromData:(NSData *)data{
CMSampleBufferRef sampleBuffer;
[data getBytes:&sampleBuffer length:sizeof(sampleBuffer)];
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress(imageBuffer,0);
uint8_t *baseAddress = (uint8_t *)CVPixelBufferGetBaseAddress(imageBuffer);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
size_t width = CVPixelBufferGetWidth(imageBuffer);
size_t height = CVPixelBufferGetHeight(imageBuffer);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef newContext = CGBitmapContextCreate(baseAddress,
width, height, 8, bytesPerRow, colorSpace,
kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
CGImageRef newImage = CGBitmapContextCreateImage(newContext);
CGContextRelease(newContext);
CGColorSpaceRelease(colorSpace);
UIImage *image= [UIImage imageWithCGImage:newImage scale:1.0
orientation:UIImageOrientationRight];
CGImageRelease(newImage);
[self.imageView performSelectorOnMainThread:@selector(setImage:)
withObject:image waitUntilDone:YES];
CVPixelBufferUnlockBaseAddress(imageBuffer,0);
[pool drain];
}
