GPUImageStillCamera 攝像頭-照相
GPUImage中GPUImageStillCamera可以調(diào)用系統(tǒng)相機(jī)疾党，并實(shí)現(xiàn)實(shí)時(shí)濾鏡,GPUImageStillCamera繼承自GPUImageVideoCamera類蚕礼，添加了捕獲照片的功能彼绷。
GPUImageVideoCamera
初始化方法：
- (id)initWithSessionPreset:(NSString *)sessionPreset cameraPosition:(AVCaptureDevicePosition)cameraPosition
sessionPreset是相機(jī)拍攝時(shí)的分辨率离陶。它的值如下
AVCaptureSessionPresetPhoto
AVCaptureSessionPresetHigh
AVCaptureSessionPresetMedium
AVCaptureSessionPresetLow
AVCaptureSessionPreset320x240
AVCaptureSessionPreset352x288
AVCaptureSessionPreset640x480
AVCaptureSessionPreset960x540
AVCaptureSessionPreset1280x720
AVCaptureSessionPreset1920x1080
AVCaptureSessionPreset3840x2160
AVCaptureSessionPresetiFrame960x540
AVCaptureSessionPresetiFrame1280x720
AVCaptureSessionPresetInputPriority
cameraPosition相機(jī)設(shè)備戴差，分為前后
AVCaptureDevicePositionFront
AVCaptureDevicePositionBack
- (void)startCameraCapture;開始捕獲
- (void)stopCameraCapture;停止捕獲
- (void)rotateCamera;切換前后攝像頭
使用大概步驟
1乱投、創(chuàng)建預(yù)覽View 即必須的GPUImageView
2咽笼、創(chuàng)建濾鏡
3、創(chuàng)建Camera 即我們要用到的GPUImageStillCamera
4戚炫、addTarget 并開始處理startCameraCapture
5剑刑、回調(diào)數(shù)據(jù)、寫入相冊
第一步：創(chuàng)建預(yù)覽View 即必須的GPUImageView
GPUImageView *primaryView = [[GPUImageView alloc] initWithFrame:mainScreenFrame];
primaryView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
第二步：創(chuàng)建濾鏡 即這里我們使用的 GPUImageSketchFilter(黑白反色)
GPUImageSketchFilter *filter = [[GPUImageSketchFilter alloc] init];
第三步：創(chuàng)建Camera 即我們要用到的GPUImageStillCamera
GPUImageStillCamera* stillCamera = [[GPUImageStillCamera alloc] init];
//設(shè)置相機(jī)方向
stillCamera.outputImageOrientation = UIInterfaceOrientationPortrait;
第四步： addTarget 并開始處理startCameraCapture
[stillCamera addTarget:filter];
[filter addTarget:primaryView];
[stillCamera startCameraCapture]; // 開始捕獲
第五步：添加一個(gè)按鈕photoCaptureButton双肤，當(dāng)按鈕點(diǎn)擊的時(shí)候進(jìn)行以下處理施掏，保存圖片到相冊
GPUImageVideoCamera 攝像頭-視頻流
GPUImageVideoCamera是GPUImageOutput的子類，提供來自攝像頭的圖像數(shù)據(jù)作為源數(shù)據(jù)茅糜，一般是響應(yīng)鏈的源頭七芭。
GPUImage使用AVFoundation框架來獲取視頻。
AVCaptureSession類從AV輸入設(shè)備的采集數(shù)據(jù)到制定的輸出蔑赘。
為了實(shí)現(xiàn)實(shí)時(shí)的圖像捕獲狸驳，要實(shí)現(xiàn)AVCaptureSession類，添加合適的輸入（AVCaptureDeviceInput）和輸出（比如 AVCaptureMovieFileOutput）
調(diào)用startRunning開始輸入到輸出的數(shù)據(jù)流米死，調(diào)用stopRunning停止數(shù)據(jù)流锌历。
需要注意的是startRunning函數(shù)會(huì)花費(fèi)一定的時(shí)間，所以不能在主線程（UI線程）調(diào)用峦筒，防止卡頓究西。
//相機(jī)
GPUImageVideoCamera* videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPreset640x480 cameraPosition:AVCaptureDevicePositionBack];
//濾鏡
GPUImageSepiaFilter *filter = [[GPUImageSepiaFilter alloc] init];
GPUImageLuminanceRangeFilter *filter1 = [[GPUImageLuminanceRangeFilter alloc]init];
//顯示view
GPUImageView *filterView = (GPUImageView *)self.view;
//組合
[videoCamera addTarget:filter];
[filter addTarget:filter1];
[filter1 addTarget:filterView];
//相機(jī)開始運(yùn)行
[videoCamera startCameraCapture];
GPUImageMovie 為視頻文件添加濾鏡
視頻處理需要用到GPUImageMovieWriter這個(gè)類，初始化方式如下：
//movieURL 是指電影的寫入地址 是：NSURL
GPUImageMovieWriter* movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(480.0, 640.0)];
其實(shí)物喷，GPUImageView和GPUImageMovieWriter是出于同一地位的卤材，都是視頻輸出類，只不過一個(gè)是輸出到屏幕峦失，一個(gè)是輸出到文件
代碼
- (void)viewDidLoad
{
[super viewDidLoad];
videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPreset640x480 cameraPosition:AVCaptureDevicePositionBack];
//輸出方向?yàn)樨Q屏
videoCamera.outputImageOrientation = UIInterfaceOrientationPortrait;
//濾鏡
filter = [[GPUImageSepiaFilter alloc] init];
//顯示view
GPUImageView *filterView = (GPUImageView *)self.view;
//組合
[videoCamera addTarget:filter];
[filter addTarget:filterView];
//相機(jī)開始運(yùn)行
[videoCamera startCameraCapture];
//設(shè)置寫入地址
NSString *pathToMovie = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/LiveMovied.m4v"];
movieURL = [NSURL fileURLWithPath:pathToMovie];
movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(480.0, 640.0)];
//設(shè)置為liveVideo
movieWriter.encodingLiveVideo = YES;
[filter addTarget:movieWriter];
//設(shè)置聲音
videoCamera.audioEncodingTarget = movieWriter;
//延遲2秒開始
[self performSelector:@selector(starWrite) withObject:nil afterDelay:2];
//延遲12秒結(jié)束
[self performSelector:@selector(stopWrite) withObject:nil afterDelay:12];
}
- (void)starWrite{
dispatch_async(dispatch_get_main_queue(), ^{
[movieWriter startRecording];
});
}
- (void)stopWrite{
dispatch_async(dispatch_get_main_queue(), ^{
videoCamera.audioEncodingTarget = nil;
[filter removeTarget:movieWriter];
[movieWriter finishRecording];
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
if ([library videoAtPathIsCompatibleWithSavedPhotosAlbum:movieURL])
{
[library writeVideoAtPathToSavedPhotosAlbum:movieURL completionBlock:^(NSURL *assetURL, NSError *error)
{
dispatch_async(dispatch_get_main_queue(), ^{
if (error) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"Video Saving Failed"
delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
} else {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Video Saved" message:@"Saved To Photo Album"
delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
}
});
}];
}
});
}
如果我們在寫入濾鏡的時(shí)候突然改變?yōu)槠渌麨V鏡怎么辦扇丛？
添加一下方法
[self performSelector:@selector(changeFilter) withObject:nil afterDelay:6];
- (void)changeFilter{
videoCamera.removeAllTargets;
filter = [[GPUImageSobelEdgeDetectionFilter alloc]init];
[videoCamera addTarget:filter];
GPUImageView *filterView = (GPUImageView *)self.view;
[filter addTarget:filterView];
[filter addTarget:movieWriter];
}
關(guān)于M4V格式：
M4V 是一個(gè)標(biāo)準(zhǔn)視頻文件格式，由蘋果公司創(chuàng)造尉辑。此種格式為 iPod 帆精、 iPhone 和 PlayStation Portable 所使用，同時(shí)此格式基于 MPEG-4 編碼第二版。M4V是一種應(yīng)用于網(wǎng)絡(luò)視頻點(diǎn)播網(wǎng)站和移動(dòng)手持設(shè)備的視頻格式卓练，是MP4格式的一種特殊類型隘蝎，其后綴常為.MP4或.M4V，其視頻編碼采用H264或H264/AVC襟企，音頻編碼采用AAC
我們可以直接使用GPUImageBeautifyFilter來代替GPUImage的原生濾鏡嘱么，那么可以直接實(shí)現(xiàn)美顏效果
基于GPUImage的實(shí)時(shí)美顏濾鏡
我們也可以參考這篇文章GPUImage詳細(xì)解析（三）- 實(shí)時(shí)美顏濾鏡
