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定义 全局 变量
///设备协调输入输出中心
AVCaptureSession *_captureSession;
///设备
AVCaptureDevice *_captureDevice;
/// 输入源
AVCaptureDeviceInput *_videoCaptureDeviceInput;
AVCaptureDeviceInput *_audioCaptureDeviceInput;
/// 视频输出
AVCaptureVideoDataOutput *_captureVideoDataOutput;
/// 音频输出
AVCaptureAudioDataOutput *_captureAudioDataOutput;
/// 队列
dispatch_queue_t my_Queue;
/// 视频 连接
AVCaptureConnection *_videoConnection;
/// 音频连接
AVCaptureConnection *_audioConnection;
// 用来显示 每一帧的 imageview
UIImageView *bufferImageView;
//写入路径
@property(nonatomic,copy)NSString *path;
/// 写入
@property(nonatomic,strong)AVAssetWriter *assetWriter;
@property(nonatomic,strong) AVAssetWriterInputPixelBufferAdaptor *adaptor;
/// 视频写入
@property(nonatomic,strong)AVAssetWriterInput *videoInput;
/// 音频写入
@property(nonatomic,strong)AVAssetWriterInput *audioInput;
- (void)initDevice {
bufferImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 64, 375, 375)];
[self.view addSubview:bufferImageView];
_captureSession = [[AVCaptureSession alloc] init];
if ([_captureSession canSetSessionPreset:AVCaptureSessionPreset640x480]) {
[_captureSession setSessionPreset:AVCaptureSessionPreset640x480];
}
// 获取后置 摄像头
_captureDevice = [self backCamera];
// 音频输入
AVCaptureDevice *audioCaptureDevice = [[AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio] firstObject];
_audioCaptureDeviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:audioCaptureDevice error:nil];
//视频输入
_videoCaptureDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:_captureDevice error:nil];
[_captureSession addInput:_videoCaptureDeviceInput];
[_captureSession addInput:_audioCaptureDeviceInput];
[_captureDevice lockForConfiguration:nil];
[_captureDevice setActiveVideoMaxFrameDuration:CMTimeMake(1,15)];
[_captureDevice setActiveVideoMinFrameDuration:CMTimeMake(1,15)];
[_captureDevice unlockForConfiguration];
// 视频输出
_captureVideoDataOutput = [[AVCaptureVideoDataOutput alloc] init];
_captureVideoDataOutput.videoSettings = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA]
forKey:(id)kCVPixelBufferPixelFormatTypeKey];
[_captureSession addOutput:_captureVideoDataOutput];
my_Queue = dispatch_queue_create("myqueue", NULL);
[_captureVideoDataOutput setSampleBufferDelegate:self queue:my_Queue];
_captureVideoDataOutput.alwaysDiscardsLateVideoFrames = YES;
// 音频输出
_captureAudioDataOutput = [[AVCaptureAudioDataOutput alloc] init];
[_captureAudioDataOutput setSampleBufferDelegate:self queue:my_Queue];
[_captureSession addOutput:_captureAudioDataOutput];
/// 视频连接
_videoConnection = [_captureVideoDataOutput connectionWithMediaType:AVMediaTypeVideo];
_videoConnection.videoOrientation = AVCaptureVideoOrientationPortrait;
/// 音频连接
_audioConnection = [_captureAudioDataOutput connectionWithMediaType:AVMediaTypeAudio];
[_captureSession startRunning];
/// 创建的时候 最好调用一下 切换前后 摄像头，这样进来 从samplebuffer转化的iamge都是向左旋转了90度，不知道为什么，好像是因为 苹果默认横向录 是正方向，以后有机会再解决
}
实现代理
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{
if (captureOutput == _captureVideoDataOutput) { // 只有是视频帧 过来才操作
CFRetain(sampleBuffer);
// 把samplebuffer 转化为图片 在方法里可做裁剪
UIImage *image = [self imageFromSampleBuffer:sampleBuffer];
// 在这你可以对图片做一些算法操作
dispatch_async(dispatch_get_main_queue(), ^{
bufferImageView.image = image;
});
CFRelease(sampleBuffer);
}
#pramark 再写入文件
if(开始写入 == NO){
return;
}
BOOL isVideo = YES;
CFRetain(sampleBuffer);
if (captureOutput != _captureVideoDataOutput) {
isVideo = NO;
}
if (writer == nil && !isVideo) {
videoPath = [NSString stringWithFormat:@"%@/Documents/movie.mp4",NSHomeDirectory()];
CMFormatDescriptionRef fmt = CMSampleBufferGetFormatDescription(sampleBuffer);
const AudioStreamBasicDescription *asbd = CMAudioFormatDescriptionGetStreamBasicDescription(fmt);
[[NSFileManager defaultManager] removeItemAtPath:videoPath error:nil];
[self initPath:videoPath videoWidth:480 videoHeight:480 channels:asbd->mChannelsPerFrame samples:asbd->mSampleRate];
}
if (CMSampleBufferDataIsReady(sampleBuffer)) {
if (writer.assetWriter.status == 0) {
if (isVideo == YES) {
[writer firstSamebuffer:sampleBuffer];
}
}
if (writer.assetWriter.status == 3) {
NSLog(@"写入失败 %@",writer.assetWriter.error);
}
if (isVideo) {
if (writer.videoInput.readyForMoreMediaData == YES) {
CMTime startTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer);
[writer encodeImageDataToVideo:resultImage time:startTime];
}
}
else{
[writer encodeAudioFrame:sampleBuffer];
}
CFRelease(sampleBuffer);
}
}
- (void)createWriter:(NSString *)path Width:(NSInteger)width Height:(NSInteger)height channels:(int)channels samples:(Float64)samples {
/// 创建writer
[[NSFileManager defaultManager] removeItemAtPath:path error:nil];
NSURL *pathUrl = [NSURL fileURLWithPath:path];
_assetWriter = [AVAssetWriter assetWriterWithURL:pathUrl fileType:AVFileTypeMPEG4 error:nil];
_assetWriter.shouldOptimizeForNetworkUse = YES;
[self initVideoInputHeight:height width:width];
[self initAudioInputChannels:channels samples:samples];
}
//初始化视频输入
- (void)initVideoInputHeight:(NSInteger)cy width:(NSInteger)cx {
//录制视频的一些配置，分辨率，编码方式等等
NSDictionary* settings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
[NSNumber numberWithInteger: cx], AVVideoWidthKey,
[NSNumber numberWithInteger: cy], AVVideoHeightKey,
nil];
//初始化视频写入类
_videoInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:settings];
//表明输入是否应该调整其处理为实时数据源的数据
_videoInput.expectsMediaDataInRealTime = YES;
// 初始化写入图像类 add by david
[self initVideoInputAdaptor];
NSParameterAssert(_videoInput);
NSParameterAssert([_assetWriter canAddInput:_videoInput]);
//将视频输入源加入
[_assetWriter addInput:_videoInput];
}
// 初始化写入图像类
- (void)initVideoInputAdaptor
{
NSDictionary *sourcePixelBufferAttributesDictionary = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:kCVPixelFormatType_32BGRA], kCVPixelBufferPixelFormatTypeKey, nil];
_adaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:_videoInput
sourcePixelBufferAttributes:sourcePixelBufferAttributesDictionary];
}
//初始化音频输入
- (void)initAudioInputChannels:(int)ch samples:(Float64)rate {
//音频的一些配置包括音频各种这里为AAC,音频通道、采样率和音频的比特率
NSDictionary *settings = [NSDictionary dictionaryWithObjectsAndKeys:
[ NSNumber numberWithInt: kAudioFormatMPEG4AAC], AVFormatIDKey,
[ NSNumber numberWithInt: ch], AVNumberOfChannelsKey,
[ NSNumber numberWithFloat: rate], AVSampleRateKey,
[ NSNumber numberWithInt: 128000], AVEncoderBitRateKey,
nil];
//初始化音频写入类
_audioInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:settings];
//表明输入是否应该调整其处理为实时数据源的数据
_audioInput.expectsMediaDataInRealTime = YES;
//将音频输入源加入
[_assetWriter addInput:_audioInput];
}
- (CVPixelBufferRef )pixelBufferFromCGImage:(CGImageRef)image size:(CGSize)size
{
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
[NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey, nil];
CVPixelBufferRef pxbuffer = NULL;
CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, size.width, size.height, kCVPixelFormatType_32BGRA, (__bridge CFDictionaryRef)options, &pxbuffer);
NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);
CVPixelBufferLockBaseAddress(pxbuffer, 0);
void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);
NSParameterAssert(pxdata != NULL);
CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(pxdata, size.width, size.height, 8, 4*size.width, rgbColorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
NSParameterAssert(context);
CGContextDrawImage(context, CGRectMake(0, 0, size.width, size.height), image);
CGColorSpaceRelease(rgbColorSpace);
CGContextRelease(context);
CVPixelBufferUnlockBaseAddress(pxbuffer, 0);
return pxbuffer;
}
// 通过抽样缓存数据创建一个UIImage对象
- (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer
{
// 为媒体数据设置一个CMSampleBuffer的Core Video图像缓存对象
CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
// 锁定pixel buffer的基地址
CVPixelBufferLockBaseAddress(imageBuffer, 0);
// 得到pixel buffer的基地址
void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer);
// 得到pixel buffer的行字节数
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
// 得到pixel buffer的宽和高
size_t width = CVPixelBufferGetWidth(imageBuffer);
size_t height = CVPixelBufferGetHeight(imageBuffer);
if (width == 0 || height == 0) {
return nil;
}
// 创建一个依赖于设备的RGB颜色空间
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
// 用抽样缓存的数据创建一个位图格式的图形上下文（graphics context）对象
CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8,
bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
//
CGAffineTransform transform = CGAffineTransformIdentity;
CGContextConcatCTM(context, transform);
// 根据这个位图context中的像素数据创建一个Quartz image对象
CGImageRef quartzImage = CGBitmapContextCreateImage(context);
// 裁剪 图片
struct CGImage *cgImage = CGImageCreateWithImageInRect(quartzImage, CGRectMake(0, 0, height, height));
// 解锁pixel buffer
CVPixelBufferUnlockBaseAddress(imageBuffer,0);
// 释放context和颜色空间
CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
// 用Quartz image创建一个UIImage对象image
UIImage *image = [UIImage imageWithCGImage:cgImage];
// UIImage *image = [UIImage imageWithCGImage:quartzImage scale:1.0 orientation:UIImageOrientationRight];
// 释放Quartz image对象
CGImageRelease(cgImage);
CGImageRelease(quartzImage);
// NSLog(@"原来的%ld %f",(long)image.size.width,image.size.height);
// image = [self image:image rotation:UIImageOrientationRight];
// NSLog(@"变换过的%ld %f",(long)image.size.width,image.size.height);
// image.imageOrientation = 2;
// CGImageRelease(cgImage);
// UIImage *resultImage = [[JBFaceDetectorHelper sharedInstance] rotateWithImage:image isFont:isFront];
return (image);
}
使用AVCapTureSession 获取每一帧sampleBuffer
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原文地址：http://www.cnblogs.com/xia0huihui/p/5803488.html
