Question

我从livephoto获得了视频，并且更多次出口这样的视频它变得比源livephoto更红。这是一个错误？
这是导出代码，最后有一个演示项目。

- (void)clipMovie:(NSString *)path block:(void (^)(BOOL success))completionBlock
    {
        UIColor *bgcolor = (UIColor *)[UIColor blackColor];

        AVURLAsset *videoasset = [[AVURLAsset alloc]initWithURL:[NSURL fileURLWithPath:path] options:nil];

        AVMutableComposition *composition = [AVMutableComposition composition];
        NSError *error;
        [composition insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoasset.duration) ofAsset:videoasset atTime:kCMTimeZero error:&error];

        AVMutableVideoCompositionInstruction *videoInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
        videoInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, composition.duration);
        videoInstruction.backgroundColor = bgcolor.CGColor;


        if ([[composition tracksWithMediaType:AVMediaTypeVideo] count] > 0)
        {
            AVAssetTrack *videoTrack = [[composition tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

            AVMutableVideoCompositionLayerInstruction *cropLayer = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];

    //        CGSize naturalSize = videoTrack.naturalSize;

            CGSize renderSize = CGSizeMake(1080, 1080);

            AVAssetTrack *videoTracktmp = [[videoasset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
            CGAffineTransform transform = videoTracktmp.preferredTransform;

            CGRect drawrect = CGRectMake(0, 0, 1080, 1080);

            [cropLayer setTransform:transform atTime:kCMTimeZero];

            CALayer *backgroundLayer = [CALayer layer];
            //        [backgroundLayer setContents:(id)self.patternBgView.image.CGImage];
            backgroundLayer.frame = CGRectMake(0, 0, renderSize.width, renderSize.height);
            [backgroundLayer setMasksToBounds:YES];
            backgroundLayer.backgroundColor = bgcolor.CGColor;

            CALayer *videoLayer = [CALayer layer];


            videoLayer.frame =  CGRectMake(drawrect.origin.x, (renderSize.height-drawrect.size.height-drawrect.origin.y), drawrect.size.width, drawrect.size.height);
            CALayer *parentLayer = [CALayer layer];
            parentLayer.frame = CGRectMake(0, 0, renderSize.width, renderSize.height);
            [parentLayer addSublayer:backgroundLayer];
            [parentLayer addSublayer:videoLayer];

            AVMutableVideoComposition *videoComposition = [AVMutableVideoComposition videoComposition];
            videoComposition.animationTool = [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer];
            videoInstruction.layerInstructions = @[cropLayer];
            videoComposition.instructions = @[videoInstruction];

            videoComposition.renderSize = CGSizeMake(renderSize.width, renderSize.height);
            videoComposition.frameDuration = CMTimeMake(1, 15);

            AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:videoasset presetName:AVAssetExportPresetHighestQuality];
            exportSession.shouldOptimizeForNetworkUse = YES;
            exportSession.videoComposition = videoComposition;
            //        exportSession.metadata = videoasset.metadata;

            NSString *path = [[NSHomeDirectory() stringByAppendingPathComponent:@"Library/Caches"] stringByAppendingPathComponent:@"a"];
            BOOL bo = [[NSFileManager defaultManager] createDirectoryAtPath:path withIntermediateDirectories:YES attributes:nil error:nil];
            NSString *result = [path stringByAppendingPathComponent:@"a.mov"];

            NSString *exportVideoPath = result;
    //        NSLog(@"%@",result);

            if ([[NSFileManager defaultManager] fileExistsAtPath:exportVideoPath]) {
                [[NSFileManager defaultManager] removeItemAtPath:exportVideoPath error:nil];
            }

            NSURL *exportURL = [NSURL fileURLWithPath:exportVideoPath];
            exportSession.outputURL = exportURL;
    //        exportSession.metadata = [self updateMetadata:videoasset.metadata];
            exportSession.outputFileType = AVFileTypeQuickTimeMovie;
            [exportSession exportAsynchronouslyWithCompletionHandler:^{
                dispatch_async(dispatch_get_main_queue(), ^{
                    switch ((int)exportSession.status) {
                        case AVAssetExportSessionStatusFailed:{
                            //                    NSLog (@"FAIL");
                            completionBlock(NO);
                            break;
                        }
                        case AVAssetExportSessionStatusCompleted: {
                            //                    NSLog (@"SUCCESS");
                            completionBlock(YES);
                            break;
                        }
                    };
                });

            }];
        }

    }

然后视频比源livephoto更红。

这里是demo link on github

运行项目
它将在1s后显示imagepicker。
选择livephoto
然后点击选择
然后新视频保存到您的相册。它变红了！

Answer 1

哎呀！做吧！

AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:videoasset presetName:AVAssetExportPresetPassthrough];

此导出选项将导致所有轨道的媒体完全按照源资源中的存储方式传递到输出，但通道无法通过的轨道，通常是由于指定的outputFileType指示的容器格式的约束。此选项不包含在-allExportPresets和-exportPresetsCompatibleWithAsset返回的数组中。

AVAssetExportSession，AVMutableVideoComposition使视频更红

1 个答案: