ios - 尝试使用PHLivePhotoView Objective-C显示实时照片时，图像元数据无效

我正在尝试在iOS设备上使用Objective-C将jpg图像和mov文件一起加载以显示实时照片，并在viewDidLoad函数中创建以下代码段来实现此目的:

- (void)viewDidLoad {
    [super viewDidLoad];

    PHLivePhotoView *photoView = [[PHLivePhotoView alloc]initWithFrame:self.view.bounds];

    NSURL *imageUrl = [[NSBundle mainBundle] URLForResource"livePhoto" withExtension"jpg"];
    NSURL *videoUrl = [[NSBundle mainBundle] URLForResource"livePhoto" withExtension"mov"];

    [PHLivePhoto requestLivePhotoWithResourceFileURLs[videoUrl, imageUrl] placeholderImage:[UIImage imageNamed"livePhoto.jpg"] targetSize:self.view.bounds.size contentModeHImageContentModeAspectFit resultHandler:^(PHLivePhoto *livePhoto, NSDictionary *info){
        NSLog(@"we are in handler");
        photoView.livePhoto = livePhoto;
        photoView.contentMode = UIViewContentModeScaleAspectFit;
        photoView.tag = 87;
        [self.view addSubview:photoView];
        [self.view sendSubviewToBack:photoView];
    }];


}

我已将文件livePhoto.jpg和livePhoto.mov拖到Xcode项目中

但是在构建此Xcode日志时，会出现以下错误:

2017-11-28 17:46:08.568455+0800 Live Photos[3669:1276778] we are in handler
2017-11-28 17:46:08.580439+0800 Live Photos[3669:1276778] we are in handler
2017-11-28 17:46:08.597147+0800 Live Photos[3669:1276806] Error: Invalid image metadata
2017-11-28 17:46:08.607881+0800 Live Photos[3669:1276806] Error: Invalid video metadata
2017-11-28 17:46:08.608329+0800 Live Photos[3669:1276778] we are in handler

有什么想法吗？谢谢。

还有另一件事要问:

为什么根据打印内容两次调用了resultHandler？

---

Best Answer-推荐答案

TL； DR

以下是存储实时照片并将其上传到服务器的代码:

1.拍摄实时照片

- (void)captureOutputAVCapturePhotoOutput *)output didFinishProcessingPhotoSampleBufferCMSampleBufferRef)photoSampleBuffer previewPhotoSampleBufferCMSampleBufferRef)previewPhotoSampleBuffer resolvedSettingsAVCaptureResolvedPhotoSettings *)resolvedSettings bracketSettingsAVCaptureBracketedStillImageSettings *)bracketSettings errorNSError *)error {
    if (error) {
        [self raiseError:error];
        return;
    }
    NSData *imageData = [AVCapturePhotoOutput JPEGPhotoDataRepresentationForJPEGSampleBuffer:photoSampleBuffer previewPhotoSampleBuffer:previewPhotoSampleBuffer];
    CIImage *image = [CIImage imageWithData:imageData];
    [self.expectedAsset addInput:image.properties]; // 1. This is the metadata (which will be lost in step 2.)
    [self.expectedAsset addInput:[UIImage imageWithCIImage:image]]; // 2. Creating image, but UIImage is not designed to contain the required metadata
}
- (void)captureOutputAVCapturePhotoOutput *)output 
didFinishProcessingLivePhotoToMovieFileAtURLNSURL *)outputFileURL durationCMTime)duration photoDisplayTimeCMTime)photoDisplayTime resolvedSettings:(AVCaptureResolvedPhotoSettings *)resolvedSettings error:(nullable NSError *)error {
    if (error) {
        [self raiseError:error];
    } else {
        [self.expectedAsset addInpututputFileURL]; // 3. Store the URL to the actual video file
    }
}

expectedAsset只是一个包含所有必需信息的对象。您可以改用NSDictionary。并且由于此代码段是> = iOS 11 API，因此这里是“不推荐使用” iOS的一个...

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunguarded-availability"
- (void)captureOutput:(AVCapturePhotoOutput *)output didFinishProcessingPhoto:(AVCapturePhoto *)photo error:(NSError *)error {
    if (error) {
        [self raiseError:error];
    } else {
        [self.expectedAsset addInput:[photo metadata]];
        [self.expectedAsset addInput:[UIImage imageWithData:[photo fileDataRepresentation]]];
    }
}
#pragma clang diagnostic pop 

2.生成NSData

- (NSData*)imageData {
        NSData *jpgData = UIImageJPEGRepresentation(self.image, 1); // This is the UIImage (without metadata) from step 2 above
        CGImageSourceRef source = CGImageSourceCreateWithData((__bridge CFDataRef) jpgData, NULL);
        NSMutableData *dest_data = [NSMutableData data];
        CFStringRef uti = CGImageSourceGetType(source);
        NSMutableDictionary *maker = [NSMutableDictionary new];
        [maker setObject:[self.imageMetadata objectForKey:(NSString*)kCGImagePropertyMakerAppleDictionary] forKey:(NSString *)kCGImagePropertyMakerAppleDictionary];    // imageMetadata is the dictionary form step 1 above
        CGImageDestinationRef destination = CGImageDestinationCreateWithData((__bridge CFMutableDataRef)dest_data,uti,1,NULL);
        CGImageDestinationAddImageFromSource(destination, source , 0, (__bridge CFDictionaryRef) maker);
        CGImageDestinationFinalize(destination);
        return dest_data;
    }

- (void)dataRepresentation:(DataRepresentationLoaded)callback {
    callback(@{@"image": self.imageData, @"video": [NSData dataWithContentsOfURL:self.livePhotoURL]}); // LivePhotoURL is the url from step 3 above
}

详细答案

这是由于视频/图像文件中的元数据错误引起的。
创建实时照片时，PHLivePhoto在kCGImagePropertyMakerAppleDictionary(这是资产标识符)中搜索键17，并将其与mov文件的com.apple.quicktime.content.identifier相匹配。 mov文件还需要在捕获静止图像时添加一个条目(com.apple.quicktime.still-image-time)。

确保您的文件未在某处进行编辑(或导出)。事件UIImageJPEGRepresentation函数将从图像中删除此数据。

这是我用来将UIImage转换为NSData的代码片段:

- (NSData*)imageData {
    NSData *jpgData = UIImageJPEGRepresentation(self.image, 1);
    CGImageSourceRef source = CGImageSourceCreateWithData((__bridge CFDataRef) jpgData, NULL);
    NSMutableData *dest_data = [NSMutableData data];
    CFStringRef uti = CGImageSourceGetType(source);
    NSMutableDictionary *maker = [NSMutableDictionary new];
    [maker setObject:[self.imageMetadata objectForKey:(NSString*)kCGImagePropertyMakerAppleDictionary] forKey:(NSString *)kCGImagePropertyMakerAppleDictionary];
    CGImageDestinationRef destination = CGImageDestinationCreateWithData((__bridge CFMutableDataRef)dest_data,uti,1,NULL);
    CGImageDestinationAddImageFromSource(destination, source , 0, (__bridge CFDictionaryRef) maker);
    CGImageDestinationFinalize(destination);
    return dest_data;
}

处理程序被调用两次，首先告诉您有关损坏的数据，第二次通知您取消进程(这是两个不同的键)。

编辑:

这是您的mov数据:

$ ffmpeg -i cf70b7de66bd89654967aeef1d557816.mov
元数据:
major_brand:qt
minor_version:0
compatible_brands:qt
creation_time:2018-01-27T11:07:38.000000Z
com.apple.quicktime.content.identifier:cf70b7de66bd89654967aeef1d557816
持续时间:00:00:15.05，开始:0.000000，比特率:1189 kb / s
流＃0:0(und):视频:h264(高)(avc1 / 0x31637661)，yuv420p(逐行)，540x960，1051 kb / s，29.84 fps，29.97 tbr，30k tbn，59.94 tbc(默认)
元数据:
creation_time:2018-01-27T11:07:38.000000Z
handler_name:核心媒体数据处理程序
编码器:“avc1”
流＃0:1(und):音频:aac(LC)(mp4a / 0x6134706D)，44100 Hz，立体声，fltp，128 kb / s(默认)
元数据:
creation_time:2018-01-27T11:07:38.000000Z
handler_name:核心媒体数据处理程序

此处缺少com.apple.quicktime.still-image-time键。

以下是元数据的外观:

元数据:
major_brand:qt
minor_version:0
compatible_brands:qt
creation_time:2017-12-15T12:41:00.000000Z
com.apple.quicktime.content.identifier:89CB44DA-D129-43F3-A0BC-2C980767B810
com.apple.quicktime.location.ISO6709:+ 51.5117 + 007.4668 + 086.000 /
com.apple.quicktime.make:苹果
com.apple.quicktime.model:iPhone X
com.apple.quicktime.software:11.1.2
com.apple.quicktime.creationdate:2017-12-15T13:41:00 + 0100
持续时间:00:00:01.63，开始:0.000000，比特率:8902 kb / s
流＃0:0(und):视频:h264(高)(avc1 / 0x31637661)，yuvj420p(pc，smpte170m / smpte432 / bt709)，1440x1080，8135 kb / s，26.94 fps，30 tbr，600 tbn，1200 tbc (默认)
元数据:
旋转90
creation_time:2017-12-15T12:41:00.000000Z
handler_name:核心媒体数据处理程序
编码器:H.264
辅助数据:
displaymatrix:旋转-90.00度
流＃0:1(und):音频:pcm_s16le(lpcm / 0x6D63706C)，44100 Hz，单声道，s16，705 kb / s(默认)
元数据:
creation_time:2017-12-15T12:41:00.000000Z
handler_name:核心媒体数据处理程序
流＃0:2(und):数据:无(mebx / 0x7862656D)，12 kb / s(默认)
元数据:
creation_time:2017-12-15T12:41:00.000000Z
handler_name:核心媒体数据处理程序
流＃0:3(und):数据:无(mebx / 0x7862656D)，43 kb / s(默认)
元数据:
creation_time:2017-12-15T12:41:00.000000Z
handler_name:核心媒体数据处理程序

仅供参考，以下是您的JPEG数据:

$ magickidentify -format％[EXIF:*] cf70b7de66bd89654967aeef1d557816.jpg
exif:ColorSpace = 1
exif:ExifImageLength = 960
exif:ExifImageWidth = 540
exif:ExifOffset = 26
exif:MakerNote = 65、112、112、108、101、32、105、79、83、0、0、1、77、77、0、1、0、17、0、2、0、0、0， 33、0、0、0、32、0、0、0、0、99、102、55、48、98、55、100、101、54、54、98、100、56、57、54、53， 52、57、54、55、97、101、101、102、49、100、53、53、55、56、49、54、0、0

关于ios - 尝试使用PHLivePhotoView Objective-C显示实时照片时，图像元数据无效，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/47528440/