前言
简单介绍下使用GPUImage以及遇到的问题，GPUImage下载地址https://github.com/BradLarson/GPUImage
引入GPUImage
引入方式可以通过三种方式，分别是pod、直接引入工程和打成静态库(.a)文件引入。
- 通过pod引用
直接在podfile里面添加GPUimage，比较简单直接 - 导入GPUImage工程
这种方式比较繁琐，需要额外配置工程，具体可参考如何正确的导入项目 - 静态库引入
直接运用下载下来的工程GPUImage.xcodeproj文件就可以生成.a文件，需要注意的是它分为模拟器和真机，还需要区分debug和release模式，在生成.a是选择Generic iOS Device生成包含多个指令集的静态库文件。
修改GPUImage文件
因为GPUImageView中使用的异步中获取了尺寸，而这个只能在主线程执行，所以第一次启动时会等待一会，需要对此做一下处理。
申明一个viewBounds变量，在initWithFrame的时候赋值：
- (void)recalculateViewGeometry;
{
runSynchronouslyOnVideoProcessingQueue(^{
CGFloat heightScaling, widthScaling;
CGSize currentViewSize = self.viewBounds.size;
// CGFloat imageAspectRatio = inputImageSize.width / inputImageSize.height;
// CGFloat viewAspectRatio = currentViewSize.width / currentViewSize.height;
CGRect insetRect = AVMakeRectWithAspectRatioInsideRect(inputImageSize, self.viewBounds);
switch(_fillMode)
{
case kGPUImageFillModeStretch:
{
widthScaling = 1.0;
heightScaling = 1.0;
}; break;
case kGPUImageFillModePreserveAspectRatio:
{
widthScaling = insetRect.size.width / currentViewSize.width;
heightScaling = insetRect.size.height / currentViewSize.height;
}; break;
case kGPUImageFillModePreserveAspectRatioAndFill:
{
// CGFloat widthHolder = insetRect.size.width / currentViewSize.width;
widthScaling = currentViewSize.height / insetRect.size.height;
heightScaling = currentViewSize.width / insetRect.size.width;
}; break;
}
imageVertices[0] = -widthScaling;
imageVertices[1] = -heightScaling;
imageVertices[2] = widthScaling;
imageVertices[3] = -heightScaling;
imageVertices[4] = -widthScaling;
imageVertices[5] = heightScaling;
imageVertices[6] = widthScaling;
imageVertices[7] = heightScaling;
});
}
需要注意如果在录制后第一帧黑屏，先确定在Build sSetting里面，Other Linker Flags 里面添加 -fobjc-arc -ObjC这两项，若还是会黑屏，可参考https://www.jianshu.com/p/c218651cc461
开启视频
采集可以设置选择前后置摄像头，设置镜像模式，GPUImageView的fillMode为kGPUImageFillModePreserveAspectRatioAndFill则全屏展示，对于iPhoneX不是16：9的样式，可设置针对于iPhoneX的样式。
self.videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPreset1280x720 cameraPosition:AVCaptureDevicePositionBack];
//Alan 为了在AVCaptureDevice上设置硬件属性，比如focusMode和exposureMode，客户端必须首先获取设备上的锁。
if ([_videoCamera.inputCamera lockForConfiguration:nil]) {
if ([_videoCamera.inputCamera isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus]) {//自动对焦
[_videoCamera.inputCamera setFocusMode:AVCaptureFocusModeContinuousAutoFocus];
}
if ([_videoCamera.inputCamera isExposureModeSupported:AVCaptureExposureModeContinuousAutoExposure]) {//自动曝光
[_videoCamera.inputCamera setExposureMode:AVCaptureExposureModeContinuousAutoExposure];
}
if ([_videoCamera.inputCamera isWhiteBalanceModeSupported:AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance]) {//自动白平衡
[_videoCamera.inputCamera setWhiteBalanceMode:AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance];
}
[_videoCamera.inputCamera unlockForConfiguration];//Alan 解锁设备，提交配置
}
_videoCamera.outputImageOrientation = UIInterfaceOrientationPortrait;//竖屏方向采集数据
[_videoCamera addAudioInputsAndOutputs];//录制的时候添加声音,添加输入源和输出源会暂时会使录制暂时卡住,所以在要使用声音的情况下要先调用该方法来防止录制被卡住。
_videoCamera.horizontallyMirrorFrontFacingCamera = YES;//前置是镜像
_videoCamera.horizontallyMirrorRearFacingCamera = NO;//后置不是镜像
_videoCamera.frameRate = 30;
[_videoCamera addTarget:self.beautyFilter];
self.filterView = [[GPUImageView alloc]initWithFrame:self.view.bounds];
_filterView.fillMode = kGPUImageFillModePreserveAspectRatioAndFill;
[self.beautyFilter addTarget:_filterView];
[self.view addSubview:_filterView];
[_videoCamera startCameraCapture];//开启摄像头
上面采集视频默认加了美颜滤镜，具体实现可以参考https://www.jianshu.com/p/6bdb4cb50f14
- (GPUImageBeautifyFilter *)beautyFilter {
if(!_beautyFilter) {
_beautyFilter = [[GPUImageBeautifyFilter alloc]init];
}
return _beautyFilter;
}
切换滤镜
在切换滤镜前需要移除它之前的target，再重新添加
[self.videoCamera removeAllTargets];
[self.filterGroup removeAllTargets];
[self.beautyFilter removeAllTargets];
if(filterType == CameraVideoFilterNone) { //不需要滤镜
[self.videoCamera addTarget:self.beautyFilter];
[self.beautyFilter addTarget:_filterView];
return ;
}
[self.filterGroup setInitialFilters:@[imageFilter]];
[self.filterGroup setTerminalFilter:imageFilter];
[self.videoCamera addTarget:self.beautyFilter];
[self.beautyFilter addTarget:self.filterGroup];
[self.filterGroup addTarget:_filterView];
- (GPUImageFilterGroup *)filterGroup {
if(!_filterGroup) {
_filterGroup = [[GPUImageFilterGroup alloc]init];
}
return _filterGroup;
}
采集视频
选择滤镜之后可以开始录制,录制完需要移除，另外再次开启时需要重新初始化MovieWriter。
- (void)videoStartRecording {
NSString *pathToMovie = [NSString stringWithFormat:@"%@/camera_video.mp4",[NSString stringWithFormat:@"%@",[NSHomeDirectory() stringByAppendingPathComponent:@"tmp"]]];
unlink([pathToMovie UTF8String]); // If a file already exists, AVAssetWriter won't let you record new frames, so delete the old movie
NSURL *movieURL = [NSURL fileURLWithPath:pathToMovie];
self.movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(720.0, 1280.0)];
_movieWriter.encodingLiveVideo = YES;
[_movieWriter setCompletionBlock:^{
}];
[_movieWriter setFailureBlock:^(NSError *error) {
}];
if(self.selectdFilterType == CameraVideoFilterNone) {
[self.beautyFilter addTarget:_movieWriter];
}else {
[self.filterGroup addTarget:_movieWriter];
}
_videoCamera.audioEncodingTarget = _movieWriter;
[_movieWriter startRecording];
}
- (void)videoFinishRecoring {
if(self.selectdFilterType == CameraVideoFilterNone) {
[self.beautyFilter removeTarget:_movieWriter];
}else {
[self.filterGroup removeTarget:_movieWriter];
}
_videoCamera.audioEncodingTarget = nil;
[_movieWriter finishRecording];
}
本地视频添加滤镜
本地视频添加滤镜，可参考GPUImage-Master里面的demo，这边需要注意的是视频旋转问题。
我们在展示本地视频和添加滤镜写入的时候，都需要处理视频旋转。
如下展示本地添加滤镜的视频：
//视频旋转角度
- (NSUInteger)degressFromVideoFileWithURL:(NSURL *)url {
NSUInteger degress = 0;
AVAsset *asset = [AVAsset assetWithURL:url];
NSArray *tracks = [asset tracksWithMediaType:AVMediaTypeVideo];
if([tracks count] > 0) {
AVAssetTrack *videoTrack = [tracks objectAtIndex:0];
CGAffineTransform t = videoTrack.preferredTransform;
if(t.a == 0 && t.b == 1.0 && t.c == -1.0 && t.d == 0){
// Portrait
degress = 90;
}else if(t.a == 0 && t.b == -1.0 && t.c == 1.0 && t.d == 0){
// PortraitUpsideDown
degress = 270;
}else if(t.a == 1.0 && t.b == 0 && t.c == 0 && t.d == 1.0){
// LandscapeRight
degress = 0;
}else if(t.a == -1.0 && t.b == 0 && t.c == 0 && t.d == -1.0){
// LandscapeLeft
degress = 180;
}
}
return degress;
}
- (void)setupVideo {
NSURL *videoPathUrl = [NSURL fileURLWithPath:self.videoPath];//本地视频路径
self.movieFile = [[GPUImageMovie alloc] initWithURL:videoPathUrl];
_movieFile.runBenchmark = YES;
_movieFile.playAtActualSpeed = YES;
_movieFile.shouldRepeat = YES;
[_movieFile addTarget:self.beautyFilter];//添加滤镜
self.filterView = [[GPUImageView alloc]initWithFrame:self.view.bounds];
_filterView.fillMode = kGPUImageFillModePreserveAspectRatio;
[self adjustVideoDegressWithUrl:videoPathUrl];//调整角度
[self.beautyFilter addTarget:_filterView];
[self.view addSubview:_filterView];
[_movieFile startProcessing];
}
//调整视频的角度
- (void)adjustVideoDegressWithUrl:(NSURL *)url {
NSInteger degress = [self degressFromVideoFileWithURL:url];
switch (degress) {
case 90:
[_filterView setInputRotation:kGPUImageRotateRight atIndex:0];
self.videoDegress = 90;
break;
case 180:
[_filterView setInputRotation:kGPUImageRotate180 atIndex:0];
self.videoDegress = 180;
break;
case 270:
[_filterView setInputRotation:kGPUImageRotateLeft atIndex:0];
self.videoDegress = 270;
break;
default:
break;
}
}
这样就可以正常显示本地视频了，切换滤镜和存储和拍摄类似。需要注意的是添加完滤镜储存的时候也需要制定旋转角度，
[kmovieFile enableSynchronizedEncodingUsingMovieWriter:kmovieWriter];
[kmovieWriter startRecordingInOrientation:CGAffineTransformMakeRotation(self.videoDegress/180.0*M_PI)];
[kmovieFile startProcessing];
视频压缩
视频压缩可以针对分辨率和码率来进行压缩，压缩分辨率，可以直接指定分辨率大小。
针对码率压缩，我们可以用https://github.com/rs/SDAVAssetExportSession
详细介绍可参考wheelsMaker的iOS视频压缩笔记
在使用的时候需要注意视频角度导致的问题
SDAVAssetExportSession *encoder = [[SDAVAssetExportSession alloc]initWithAsset:avAsset];
encoder.outputFileType = AVFileTypeMPEG4;
encoder.outputURL = [NSURL fileURLWithPath:zipPath];
CGFloat videoWidth = 720.0;
CGFloat videoHeight = 1280.0;
NSArray *tracks = [avAsset tracksWithMediaType:AVMediaTypeVideo];
AVAssetTrack *videoTrack;
if([tracks count] > 0) {
videoTrack = [tracks objectAtIndex:0];
videoWidth = videoTrack.naturalSize.width;
videoHeight = videoTrack.naturalSize.height;
}
if(videoTrack && [NBCameraVideoTools degressFromVideoFileWithURL:[NSURL fileURLWithPath:originalPath]]%180 != 0) {
videoWidth = videoTrack.naturalSize.height;
videoHeight = videoTrack.naturalSize.width;
}
encoder.videoSettings = @{AVVideoCodecKey: AVVideoCodecH264,AVVideoWidthKey: @(videoWidth),AVVideoHeightKey: @(videoHeight),AVVideoCompressionPropertiesKey: @{AVVideoAverageBitRateKey: @1000000,AVVideoProfileLevelKey: AVVideoProfileLevelH264High40}};
encoder.audioSettings = @{AVFormatIDKey: @(kAudioFormatMPEG4AAC),AVNumberOfChannelsKey: @2,AVSampleRateKey: @44100,AVEncoderBitRateKey: @128000};
[encoder exportAsynchronouslyWithCompletionHandler:^{
if (encoder.status == AVAssetExportSessionStatusCompleted){
NSLog(@"Video export succeeded");
}else if (encoder.status == AVAssetExportSessionStatusCancelled){
NSLog(@"Video export cancelled");
}else{
NSLog(@"Video export failed with error: %@ (%d)", encoder.error.localizedDescription, encoder.error.code);
}
dispatch_async(dispatch_get_main_queue(), ^{
showTipsInCenter([NSString stringWithFormat:@"处理完成，状态：%d",[encoder status]]);
});
}];
其他
还有视频水印、合成就不一一介绍了，网上有很多方法，也都没啥问题。再使用GPUImage的时候，最好先去运用它的demo，看下它的一些滤镜实现使用方法。
后续遇到的问题
1.[GPUImageMovie endProcessing]的野指针异常，概率比较低
出现原因为movie已经置空，write后置空，而且在不同的线程，所以写入时可能异常。
解决方案参考：数数GPUImage里那些未知的坑
2.SEGV_ACCERR [GPUImageContext presentBufferForDisplay]异常
这个问题是锁屏后再进入出现
原因是iOS不支持appWillResignActive进行OpenGL渲染,所以切后台之前要调用glfinish()，将缓冲区中的指令(无论是否为满)立刻送给图形硬件执行，glfinish()会等待图形硬件执行完才返回。
需要注意的是：在iOS11这个方法可能执行两遍。
解决方法为：
runSynchronouslyOnVideoProcessingQueue(^{
glFinish();
});
可参考：GPUImage presentBufferForDisplay崩溃问题
参考：
iOS开发-美颜相机、短视频（GPUImage的使用）
https://github.com/rs/SDAVAssetExportSession
iOS视频压缩笔记
如何正确的导入项目
iOS设备闪光灯的使用
源码级别对GPUImage进行剖析 以及 尝试
数数GPUImage里那些未知的坑
GPUImage presentBufferForDisplay崩溃问题