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asset
AVAsset *myAsset = [[AVURLAsset alloc] initWithURL:movUrl options:nil];
NSParameterAssert(myAsset);
//初始化AVAssetImageGenerator
self.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+1
dispatch_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1
dispatch_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 = [AVAssetWriterInput
assetWriterInputWithMediaType:AVMediaTypeVideo
outputSettings: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Adaptor
self.adaptor = [AVAssetWriterInputPixelBufferAdaptor
assetWriterInputPixelBufferAdaptorWithAssetWriterInput:self.writerInput
sourcePixelBufferAttributes: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 = nil
status=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;
}