本文介绍了iOS5 AVFoundation图像到视频的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试从单张图片创建一个视频，并将其保存到我的照片库中，我一直在谷歌上搜索多年 - 并且无法找到解决方案。
I'm trying to create a video from a single image, and save it to my photos library, I've been googling around for ages - and cannot find a solution.
我有这段代码：
@autoreleasepool {
NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:[NSString stringWithFormat:@"Documents/movie2.mp4"]];
UIImage *img = [UIImage imageWithData:[[self imageDataArrya]objectAtIndex:0]imageData];
[self writeImageAsMovie:img toPath:path size:CGSizeMake(640, 960) duration:10];
UISaveVideoAtPathToSavedPhotosAlbum (path,self, @selector(video:didFinishSavingWithError: contextInfo:), nil);
}
我在后台线程中调用上述方法。这是'writeImageAsMovie'的代码：
I call the above mentioned method in a background thread. This is the code for 'writeImageAsMovie':
- (void)writeImageAsMovie:(UIImage*)image toPath:(NSString*)path size:(CGSize)size duration:(int)duration {
NSError *error = nil;
AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:
[NSURL fileURLWithPath:path] fileType:AVFileTypeQuickTimeMovie
error:&error];
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
[NSNumber numberWithInt:size.width], AVVideoWidthKey,
[NSNumber numberWithInt:size.height], AVVideoHeightKey,
nil];
[self setInput:[AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo
outputSettings:videoSettings]];
AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor
assetWriterInputPixelBufferAdaptorWithAssetWriterInput:input
sourcePixelBufferAttributes:nil];
[videoWriter addInput:input];
[videoWriter startWriting];
[videoWriter startSessionAtSourceTime:kCMTimeZero];
CVPixelBufferRef buffer = [self pixelBufferFromCGImage:image.CGImage];
[adaptor appendPixelBuffer:buffer withPresentationTime:kCMTimeZero];
[adaptor appendPixelBuffer:buffer withPresentationTime:CMTimeMake(duration-1, 2)];
[input markAsFinished];
[videoWriter endSessionAtSourceTime:CMTimeMake(duration, 2)];
[videoWriter finishWriting];
}
转换的实用方法CVPixelBufferRef的图像：
The utility method for converting an Image to a CVPixelBufferRef:
- (CVPixelBufferRef) pixelBufferFromCGImage: (CGImageRef) image {
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
[NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
nil];
CVPixelBufferRef pxbuffer = NULL;
CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault,
self.view.frame.size.width,
self.view.frame.size.height,
kCVPixelFormatType_32ARGB,
(__bridge CFDictionaryRef) options,
&pxbuffer);
CVPixelBufferLockBaseAddress(pxbuffer, 0);
void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);
CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(pxdata, self.view.frame.size.width,
self.view.frame.size.height, 8, 4*self.view.frame.size.width, rgbColorSpace,
kCGImageAlphaNoneSkipFirst);
CGContextConcatCTM(context, CGAffineTransformMakeRotation(0));
CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image),
CGImageGetHeight(image)), image);
CGColorSpaceRelease(rgbColorSpace);
CGContextRelease(context);
CVPixelBufferUnlockBaseAddress(pxbuffer, 0);
return pxbuffer;
}
现在，如果我尝试从模拟器运行代码，它会给我一个错误说数据已损坏。
Now if I try to run the code from the Simulator, it gives me an error saying that the data is corrupt.
如果我在我的设备上运行它，它会将2秒的视频保存到我的照片库，但它只有绿色，我的图像不是'在那里。
If I run it on my device, it saves a 2 second video to my photo library but its only green, my image isn't in there.
任何帮助将不胜感激：）
Any help will be appreciated :)
推荐答案
我完成了这项工作 - 抱歉，我今天没有看到你的回复。
这是我使用的：
I totally got this working - sorry I didn't see your reply before today.This is what I used:
创建临时文件
NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:[NSString stringWithFormat:@"Documents/flipimator-tempfile.mp4"]];
//overwrites it if it already exists.
if([fileManager fileExistsAtPath:path])
[fileManager removeItemAtPath:path error:NULL];
调用导出图像方法将图像保存到临时文件：
[self exportImages:frames
asVideoToPath:path
withFrameSize:imageSize
framesPerSecond:fps];
将临时文件保存到相册：
UISaveVideoAtPathToSavedPhotosAlbum (path,self, @selector(video:didFinishSavingWithError: contextInfo:), nil);
- (void)video:(NSString *) videoPath didFinishSavingWithError: (NSError *) error contextInfo: (void *) contextInfo {
NSLog(@"Finished saving video with error: %@", error);
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Done"
message:@"Movie succesfully exported."
delegate:nil
cancelButtonTitle:@"OK"
otherButtonTitles:nil, nil];
[alert show];
}
exportImages方法的代码：
- (void)exportImages:(NSArray *)imageArray
asVideoToPath:(NSString *)path
withFrameSize:(CGSize)imageSize
framesPerSecond:(NSUInteger)fps {
NSLog(@"Start building video from defined frames.");
NSError *error = nil;
AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:
[NSURL fileURLWithPath:path] fileType:AVFileTypeQuickTimeMovie
error:&error];
NSParameterAssert(videoWriter);
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
[NSNumber numberWithInt:imageSize.width], AVVideoWidthKey,
[NSNumber numberWithInt:imageSize.height], AVVideoHeightKey,
nil];
AVAssetWriterInput* videoWriterInput = [AVAssetWriterInput
assetWriterInputWithMediaType:AVMediaTypeVideo
outputSettings:videoSettings];
AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor
assetWriterInputPixelBufferAdaptorWithAssetWriterInput:videoWriterInput
sourcePixelBufferAttributes:nil];
NSParameterAssert(videoWriterInput);
NSParameterAssert([videoWriter canAddInput:videoWriterInput]);
videoWriterInput.expectsMediaDataInRealTime = YES;
[videoWriter addInput:videoWriterInput];
//Start a session:
[videoWriter startWriting];
[videoWriter startSessionAtSourceTime:kCMTimeZero];
CVPixelBufferRef buffer = NULL;
//convert uiimage to CGImage.
int frameCount = 0;
for(UIImage * img in imageArray) {
buffer = [self pixelBufferFromCGImage:[img CGImage] andSize:imageSize];
BOOL append_ok = NO;
int j = 0;
while (!append_ok && j < 30) {
if (adaptor.assetWriterInput.readyForMoreMediaData) {
//print out status::
NSString *border = @"**************************************************";
NSLog(@"\n%@\nProcessing video frame (%d,%d).\n%@",border,frameCount,[imageArray count],border);
CMTime frameTime = CMTimeMake(frameCount,(int32_t) fps);
append_ok = [adaptor appendPixelBuffer:buffer withPresentationTime:frameTime];
if(!append_ok){
NSError *error = videoWriter.error;
if(error!=nil) {
NSLog(@"Unresolved error %@,%@.", error, [error userInfo]);
}
}
}
else {
printf("adaptor not ready %d, %d\n", frameCount, j);
[NSThread sleepForTimeInterval:0.1];
}
j++;
}
if (!append_ok) {
printf("error appending image %d times %d\n, with error.", frameCount, j);
}
frameCount++;
}
//Finish the session:
[videoWriterInput markAsFinished];
[videoWriter finishWriting];
NSLog(@"Write Ended");
}
方法的参数
- imageArray：UIImage的NSArray。
- 路径：处理时写入的临时路径（temp上面定义）。
- imageSize：视频的大小（以像素为单位）（宽度和高度）。
- fps：应显示多少图像每秒在视频中。
- imageArray : NSArray of UIImage.
- path : Temporary path to write to while you process (temp defined above).
- imageSize : The size of the video in pixels (width, and height).
- fps : How many images should be displayed per second in the video.
希望它有所帮助！
对格式化感到抱歉 - 我我仍然是StackOverflow.com的新手。
Hope it helps!Sorry about the formatting - I'm still very new to StackOverflow.com.
这是我使用代码的地方：
This is where I used the code: http://www.youtube.com/watch?v=DDckJyF2bnA
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