视频分解图片,图片合成视频

工作当中用到了相关的技术,现在特别记录一下

分解视频


//分解视频
- (void)resolveMovWithUrl:(NSURL *)movUrl{//得到url的资源,转为assetAVAsset *myAsset = [[AVURLAsset alloc] initWithURL:movUrl options:nil];NSParameterAssert(myAsset);//初始化AVAssetImageGeneratorself.imageGenerator = [[AVAssetImageGenerator alloc] initWithAsset:myAsset] ;self.imageGenerator.appliesPreferredTrackTransform = YES;//加这句话,取出的是正确方向的图片self.imageGenerator.requestedTimeToleranceBefore = kCMTimeZero;self.imageGenerator.requestedTimeToleranceAfter = kCMTimeZero;//得到秒数Float64 _durationSeconds = CMTimeGetSeconds([myAsset duration]);__block float Second = 0.0;__block int num = 0;NSString *path = [self backPath];NSLog(@"%@",path);dispatch_semaphore_t sem = dispatch_semaphore_create(0);dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{dispatch_async(dispatch_get_main_queue(), ^{[MBProgressHUD showHUDAddedTo:self.view animated:YES];});while ((_durationSeconds - Second)>0) {NSLog(@"%f",_durationSeconds - Second);CMTime rTime = CMTimeMakeWithSeconds(Second, NSEC_PER_SEC);dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{@autoreleasepool{//根据帧数取出图片CGImageRef image= [self.imageGenerator copyCGImageAtTime:rTime actualTime:NULL error:NULL];if (image){UIImage *img = [[UIImage alloc] initWithCGImage:image];NSData *imageData = UIImagePNGRepresentation(img);NSString *pathNum = [path stringByAppendingPathComponent:[NSString stringWithFormat:@"%d.png",num]];[imageData writeToFile:pathNum atomically:NO];CGImageRelease(image);NSString *actualTimeString =CFBridgingRelease(CMTimeCopyDescription(NULL, rTime));NSLog(@"photo:%d",num);NSLog(@"%@",actualTimeString);//调用dispatch_semaphore_signal函数，使计数器+1dispatch_semaphore_signal(sem);}else{dispatch_async(dispatch_get_main_queue(), ^{[MBProgressHUD hideAllHUDsForView:self.view animated:YES];});}}});Second +=0.083;//一直等待，直到信号量计数器大于等于1dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER);num+=1;}dispatch_async(dispatch_get_main_queue(), ^{num = 0;Second = 0.0;[MBProgressHUD hideAllHUDsForView:self.view animated:YES];});});}

图片合成视频

- (void)initRecord
{//是否是第一次添加图片self.firstImgAdded = FALSE;//video路径NSString* fileName = [NSString stringWithFormat:@"%d.mov", (int)[[NSDate date] timeIntervalSince1970]];self.videoPath = [NSString stringWithFormat:@"%@/%@", [self getLibarayPath], fileName];//设置一个gcd队列writeQueue = dispatch_queue_create("recording_queue", DISPATCH_QUEUE_PRIORITY_DEFAULT);CGSize frameSize = imageRect.size;NSError* error = nil;//创建写入对象self.videoWriter = [[AVAssetWriter alloc] initWithURL:[NSURL fileURLWithPath:self.videoPath] fileType:AVFileTypeQuickTimeMovie error:&error];//如果出错,打印错误内容if(error){NSLog(@"error creating AssetWriter: %@",[error description]);self.videoWriter = nil;return;}//设置参数NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:AVVideoCodecH264, AVVideoCodecKey,[NSNumber numberWithInt:frameSize.width], AVVideoWidthKey,[NSNumber numberWithInt:frameSize.height], AVVideoHeightKey,nil];//输入对象self.writerInput = [AVAssetWriterInputassetWriterInputWithMediaType:AVMediaTypeVideooutputSettings:videoSettings];//属性设置NSMutableDictionary *attributes = [[NSMutableDictionary alloc] init];[attributes setObject:[NSNumber numberWithUnsignedInt:kCVPixelFormatType_32ARGB] forKey:(NSString*)kCVPixelBufferPixelFormatTypeKey];[attributes setObject:[NSNumber numberWithUnsignedInt:frameSize.width] forKey:(NSString*)kCVPixelBufferWidthKey];[attributes setObject:[NSNumber numberWithUnsignedInt:frameSize.height] forKey:(NSString*)kCVPixelBufferHeightKey];//通过属性和writerInput 创建一个新的Adaptorself.adaptor = [AVAssetWriterInputPixelBufferAdaptorassetWriterInputPixelBufferAdaptorWithAssetWriterInput:self.writerInputsourcePixelBufferAttributes:attributes];//添加输入,必须在开始写入之前[self.videoWriter addInput:self.writerInput];self.writerInput.expectsMediaDataInRealTime = YES;//开始写入[self.videoWriter startWriting];[self.videoWriter startSessionAtSourceTime:kCMTimeZero];
}#pragma mark - 视频合成
static int count = 0;
- (void)startCamera
{NSMutableArray *arr = [self allFilesAtPath:[self backPath]];dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{dispatch_async(dispatch_get_main_queue(), ^{[MBProgressHUD showHUDAddedTo:self.view animated:YES];});while (arr.count -count) {UIImage *image = [UIImage imageWithContentsOfFile:[NSString stringWithFormat:@"%@/%d.png",[self backPath],count]];CGImageRef image1 = image.CGImage;[self writeImage:image1 withIndex:count];NSLog(@"%d",count);count ++;}[self.writerInput markAsFinished];[self.videoWriter finishWriting];//        [self combineWithAudio:num];dispatch_async(dispatch_get_main_queue(), ^{count = 0;[MBProgressHUD hideAllHUDsForView:self.view animated:YES];});});
}- (void)writeImage:(CGImageRef)img withIndex:(NSInteger)curCount
{CVPixelBufferRef buffer = NULL;if (self.videoWriter == nil){NSLog(@"error~~~~~~~~~~~");}if (self.firstImgAdded == FALSE){buffer = [self pixelBufferFromCGImage:img];BOOL result = [self.adaptor appendPixelBuffer:buffer withPresentationTime:kCMTimeZero];if (result == NO) //failes on 3GS, but works on iphone 4{NSLog(@"failed to append buffer");}if(buffer){CVBufferRelease(buffer);}self.firstImgAdded = TRUE;}else{if (self.adaptor.assetWriterInput.readyForMoreMediaData){CMTime frameTime = CMTimeMake(1, FramePerSec);CMTime lastTime = CMTimeMake(curCount, FramePerSec);CMTime presentTime = CMTimeAdd(lastTime, frameTime);buffer = [self pixelBufferFromCGImage:img];BOOL result = [self.adaptor appendPixelBuffer:buffer withPresentationTime:presentTime];if (result == NO) //failes on 3GS, but works on iphone 4{NSLog(@"failed to append buffer");NSLog(@"The error is %@", [self.videoWriter error]);}else{NSLog(@"write ok");}if(buffer){CVBufferRelease(buffer);}}else{NSLog(@"error");}}}- (CVPixelBufferRef)pixelBufferFromCGImage:(CGImageRef)image
{NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:TRUE], kCVPixelBufferCGImageCompatibilityKey,[NSNumber numberWithBool:TRUE],kCVPixelBufferCGBitmapContextCompatibilityKey,nil];//是否兼容CVPixelBufferRef pxbuffer = NULL;CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, imageRect.size.width,imageRect.size.height, kCVPixelFormatType_32ARGB, (__bridge CFDictionaryRef) options,&pxbuffer);//返回kCVReturnSuccess kCFAllocatorDefault = nilstatus=status;NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);//判断类型CVPixelBufferLockBaseAddress(pxbuffer, 0);//访问地址void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);NSParameterAssert(pxdata != NULL);CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();CGContextRef context = CGBitmapContextCreate(pxdata, imageRect.size.width,imageRect.size.height, 8, 4*imageRect.size.width, rgbColorSpace,kCGImageAlphaNoneSkipFirst);NSParameterAssert(context);CGContextConcatCTM(context, CGAffineTransformMakeRotation(0));CGContextDrawImage(context, CGRectMake(0, 0, imageRect.size.width, imageRect.size.height), image);CGColorSpaceRelease(rgbColorSpace);CGContextRelease(context);CVPixelBufferUnlockBaseAddress(pxbuffer, 0);return pxbuffer;
}

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视频分解图片,图片合成视频

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