我使用以下代码从图像创建视频。

当我从从网络下载的相机胶卷或屏幕截图中选择图像时，此代码工作正常，但选择的从相机拍摄的图像在电影中显示放大。

我不知道相机的图像有什么问题。

谁能帮我解决这个问题。

       -(IBAction)createV:(id)sender
    {
NSString *documentsDirectory = [NSHomeDirectory()
                                stringByAppendingPathComponent:@"Documents"];
NSString *videoOutputPath = [documentsDirectory stringByAppendingPathComponent:@"test_output.mp4"];

CGSize imageSize = [DatabaseAccess getusersetsize];

double nospf =[[[NSUserDefaults standardUserDefaults] valueForKey:@"duration"] intValue];
NSUInteger fps = 10;

NSMutableArray *imageArray;// = [DatabaseAccess getimagelist:@"select imgname from tbl_userimage"];
NSArray* imagePaths = [DatabaseAccess getimagelist:@"select imgname,strftime('%d-%m-%Y', tdate) as tdate from tbl_userimage"];
imageArray = [[NSMutableArray alloc] initWithCapacity:imagePaths.count];
int i=0;
for (NSString* path in [imagePaths valueForKey:@"image"] )
{
    if ([[NSUserDefaults standardUserDefaults] boolForKey:@"disdate"])
    {
        CGSize imgsize = [DatabaseAccess getusersetsize];

        //[imageArray addObject:[[DatabaseAccess drawText:[[imagePaths valueForKey:@"date"] objectAtIndex:i] inImage:[UIImage imageWithContentsOfFile:[DatabaseAccess documentsPathForFileName:path]] atPoint:CGPointMake(imgsize.width-250,imgsize.height-60) ] fixOrientation]];
        [imageArray addObject:[DatabaseAccess drawText:[[imagePaths valueForKey:@"date"] objectAtIndex:i] inImage:[UIImage imageWithContentsOfFile:[DatabaseAccess documentsPathForFileName:path]] atPoint:CGPointMake(imgsize.width-250,imgsize.height-60) ]];
    }
    else
    {
        [imageArray addObject:[UIImage imageWithContentsOfFile:[DatabaseAccess documentsPathForFileName:path]]];
        NSLog(@"%@",path);
       // [imageArray addObject:[UIImage imageNamed:path]];
    }
    i++;
}
[self exportImages:imageArray asVideoToPath:videoOutputPath withFrameSize:imageSize framesPerSecond:fps numberOfSecondsPerFrame:nospf];
   }






   - (void)exportImages:(NSMutableArray *)imageArray asVideoToPath:(NSString *)videoOutputPath withFrameSize:(CGSize)imageSize framesPerSecond:(NSUInteger)fps numberOfSecondsPerFrame:(double)numberOfSecondsPerFrame {

NSError *error = nil;
NSString *documentsDirectory = [NSHomeDirectory()
                                stringByAppendingPathComponent:@"Documents"];


NSFileManager *fileMgr = [NSFileManager defaultManager];


if ([fileMgr removeItemAtPath:videoOutputPath error:&error] != YES)
    NSLog(@"Unable to delete file: %@", [error localizedDescription]);


//////////////     end setup    ///////////////////////////////////

NSLog(@"Start building video from defined frames.");

AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:
                              [NSURL fileURLWithPath:videoOutputPath] fileType:AVFileTypeMPEG4 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;
//double numberOfSecondsPerFrame = 6;
double frameDuration = fps * numberOfSecondsPerFrame;

//for(VideoFrame * frm in imageArray)
NSLog(@"**************************************************");
for(UIImage * img in imageArray)
{



    //UIImage * img = frm._imageFrame;
    buffer = [self pixelBufferFromCGImage:[img CGImage]];

    BOOL append_ok = NO;
    int j = 0;
    while (!append_ok && j < 30) {
        if (adaptor.assetWriterInput.readyForMoreMediaData)  {
            //print out status:
            NSLog(@"Processing video frame (%d,%lu)",frameCount,(unsigned long)[imageArray count]);
            CMTime frameTime = CMTimeMake(frameCount,(int32_t) numberOfSecondsPerFrame);
            //CMTime frameTime = CMTimeMake(frameCount*frameDuration,(int32_t) fps);
            // NSLog(@"%@",frameTime);
            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++;
}
NSLog(@"**************************************************");

//Finish the session:
[videoWriterInput markAsFinished];
[videoWriter finishWriting];
NSLog(@"Write Ended");
[self playMovie:videoOutputPath];
}




- (CVPixelBufferRef) pixelBufferFromCGImage: (CGImageRef) image {

// CGSize size = CGSizeMake(400, 200);

CGSize size = [DatabaseAccess getusersetsize];

NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                         [NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
                         [NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
                         nil];
CVPixelBufferRef pxbuffer = NULL;

CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault,
                                      size.width,
                                      size.height,
                                      kCVPixelFormatType_32ARGB,
                                      (__bridge CFDictionaryRef) options,
                                      &pxbuffer);
if (status != kCVReturnSuccess){
    NSLog(@"Failed to create pixel buffer");
}

CVPixelBufferLockBaseAddress(pxbuffer, 0);
void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);

CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(pxdata, size.width,
                                             size.height, 8, 4*size.width, rgbColorSpace,
                                             kCGImageAlphaPremultipliedFirst);
//kCGImageAlphaNoneSkipFirst);
NSParameterAssert(context);
//CGContextConcatCTM(context, frameTransform);
CGContextConcatCTM(context, CGAffineTransformMakeRotation(0));
CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image),
                                       CGImageGetHeight(image)), image);
CGColorSpaceRelease(rgbColorSpace);
CGContextRelease(context);

CVPixelBufferUnlockBaseAddress(pxbuffer, 0);

return pxbuffer;
 }

最佳答案

我已经使用这段代码解决了图像放大的问题

-(UIImage*)scaleImage:(UIImage*)image toSize:(CGSize)newSize 
{
    UIGraphicsBeginImageContext(newSize);
    [image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

在将其转换为 CGImage 之前调整 UIImage 的大小， 确保以 16 的倍数调整 image.width 的大小。

CGSize your_size = CGSizeMake(1600, 800);
UIImage *tempImg = [self scaleImage:img toSize:your_size..];
buffer = [self pixelBufferFromCGImage:[tempImg CGImage]]; 

关于ios - 从相机胶卷的图像创建视频 - iOS sdk，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25863731/