AVCapture在iOS 7中捕获并获得60 fps的帧缓冲区

概述我正在开发一个应用程序,需要尽可能多的fps捕获帧缓冲区.我已经弄清楚如何强制 iphone以60 fps捕获 - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection 我正在开发一个应用程序,需要尽可能多的fps捕获帧缓冲区.我已经弄清楚如何强制 iphone以60 fps捕获

- (voID)captureOutput:(AVCaptureOutput *)captureOutput dIDOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection

方法被称为只有15次,这意味着iPhone降级捕获输出到15 fps.

有没有人面临这样的问题？是否有可能增加捕获帧速率？

更新我的代码：

camera = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVIDeo];if([camera isTorchModeSupported:AVCapturetorchModeOn]) {   [camera lockForConfiguration:nil];   camera.torchMode=AVCapturetorchModeOn;   [camera unlockForConfiguration];}[self configureCameraForHighestFrameRate:camera];// Create a AVCaptureinput with the camera deviceNSError *error=nil;AVCaptureinput* camerainput = [[AVCaptureDeviceinput alloc] initWithDevice:camera error:&error];if (camerainput == nil) {   NSLog(@"Error to create camera capture:%@",error);}// Set the outputAVCaptureVIDeoDataOutput* vIDeoOutput = [[AVCaptureVIDeoDataOutput alloc] init];// create a queue to run the capture ondispatch_queue_t captureQueue=dispatch_queue_create("captureQueue",NulL);// setup our delegate[vIDeoOutput setSampleBufferDelegate:self queue:captureQueue];// configure the pixel formatvIDeoOutput.vIDeoSettings = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA],(ID)kCVPixelBufferPixelFormatTypeKey,nil];// Add the input and output[captureSession addinput:camerainput];[captureSession addOutput:vIDeoOutput];

我在这里采用了configureCameraForHighestFrameRate方法https://developer.apple.com/library/mac/documentation/AVFoundation/Reference/AVCaptureDevice_Class/Reference/Reference.html

解决方法 我在iPhone 5上获得了60 fps的采样率,在iPhone 5上采用了120 fps,无论是在捕获输出中进行实时运动检测还是使用AVAssetWriter将帧保存到视频中.

您必须将AVCaptureSession设置为支持60 fps的格式：

AVsession = [[AVCaptureSession alloc] init];AVCaptureDevice *vIDeoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVIDeo];AVCaptureDeviceinput *capinput = [AVCaptureDeviceinput deviceinputWithDevice:vIDeoDevice error:&error];if (capinput) [AVsession addinput:capinput];for(AVCaptureDeviceFormat *vFormat in [vIDeoDevice formats] ) {    CMFormatDescriptionRef description= vFormat.formatDescription;    float maxrate=((AVFrameRaterange*)[vFormat.vIDeoSupportedFrameRateranges objectAtIndex:0]).maxFrameRate;    if(maxrate>59 && CMFormatDescriptionGetMediaSubType(description)==kCVPixelFormatType_420YpCbCr8BiPlanarFullRange)    {        if ( YES == [vIDeoDevice lockForConfiguration:NulL] )         {           vIDeoDevice.activeFormat = vFormat;           [vIDeoDevice setActiveVIDeoMinFrameDuration:CMTimeMake(10,600)];           [vIDeoDevice setActiveVIDeoMaxFrameDuration:CMTimeMake(10,600)];           [vIDeoDevice unlockForConfiguration];           NSLog(@"formats  %@ %@ %@",vFormat.mediaType,vFormat.formatDescription,vFormat.vIDeoSupportedFrameRateranges);        }     }}prevLayer = [AVCaptureVIDeoPrevIEwLayer layerWithSession: AVsession];prevLayer.vIDeoGravity = AVLayerVIDeoGravityResizeAspectFill;[self.vIEw.layer addSublayer: prevLayer];AVCaptureVIDeoDataOutput *vIDeoOut = [[AVCaptureVIDeoDataOutput alloc] init];dispatch_queue_t vIDeoQueue = dispatch_queue_create("vIDeoQueue",NulL);[vIDeoOut setSampleBufferDelegate:self queue:vIDeoQueue];vIDeoOut.vIDeoSettings = @{(ID)kCVPixelBufferPixelFormatTypeKey: @(kCVPixelFormatType_32BGRA)};vIDeoOut.alwaysdiscardsLateVIDeoFrames=YES;if (vIDeoOut){    [AVsession addOutput:vIDeoOut];    vIDeoConnection = [vIDeoOut connectionWithMediaType:AVMediaTypeVIDeo];}

如果您想使用AVAssetWriter写入一个文件,另外两个评论.不要使用pixelAdaptor,只需要添加样品

[vIDeoWriterinput appendSampleBuffer:sampleBuffer]

其次,当设置assetwriter使用

[AVAssetWriterinput assetWriterinputWithMediaType:AVMediaTypeVIDeo                                   outputSettings:vIDeoSettings                                  sourceFormatHint:formatDescription];

sourceFormatHint在写入速度方面有所不同.

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