ios - AVAssetExportSession 间歇性错误 11820 "Cannot Complete Export"Suggestion=再次尝试导出

Question

EXPORT STATUS 4 Error Domain=AVFoundationErrorDomain Code=-11820 "Cannot Complete Export" UserInfo={NSLocalizedDescription=Cannot Complete Export, NSLocalizedRecoverySuggestion=Try exporting again.}

尝试导出包含 AVMutableVideoCompositionLayerInstruction 的 AVMutableComposition 和使用 的 AVMutableVideoComposition 时遇到间歇性错误AVAssetExportSession.

目标是合并无限数量的视频并使用 layerInstructions 在剪辑之间应用过渡。

附言错误不一致。它在尝试合并 5 个剪辑和 18 个剪辑时有效，但在尝试合并 17 个剪辑时无效。

我已经在下面发布了我的代码。非常感谢任何帮助。

编辑:问题似乎与多个 AVMutableCompositionTrack(s) 的创建有关。如果创建超过 15 或 16 个，则会发生错误。但是，我认为创建多个 AVMutableCompositionTrack 是重叠所有视频和创建重叠过渡的必要条件。

编辑 2:选择较短的视频时，会在发生错误之前处理更多的视频。因此，它看起来像是一个内存问题，轨道正在被释放。但是，基于内存管理工具似乎没有内存泄漏。

-(void)prepareMutableCompositionForPlayback{
AVMutableComposition *mutableComposition = [[AVMutableComposition alloc] init];
AVMutableVideoCompositionInstruction *mainInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
mainInstruction.backgroundColor = [[UIColor blackColor] CGColor];

NSMutableArray *instructionsArray = [[NSMutableArray alloc] init];

videoStartTime = kCMTimeZero;

for(int i = 0; i < videoAssetsArray.count; i++){
    AVAsset *videoAsset = [videoAssetsArray objectAtIndex:i];
    CMTime currentVideoDuration = [videoAsset duration];

    AVMutableCompositionTrack *videoTrack = [mutableComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
    [videoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, currentVideoDuration) ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:videoStartTime error:nil];

    CGSize videoSize = [videoTrack naturalSize];

    if([videoAsset tracksWithMediaType:AVMediaTypeAudio].count > 0){
        AVMutableCompositionTrack *audioTrack = [mutableComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
        [audioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, currentVideoDuration) ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:videoStartTime error:nil];
    }

    //INSTRUCTIONS - TRANSITIONS
    AVMutableVideoCompositionLayerInstruction *layerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];

    int transitionNumber = [[videoTransitionsArray objectAtIndex:i] intValue];
    float transitionDuration = [[videoTransitionsDurationArray objectAtIndex:i] floatValue];

    if(i == 0){
        [layerInstruction setOpacityRampFromStartOpacity:1.0 toEndOpacity:0.0 timeRange:CMTimeRangeMake(CMTimeSubtract(currentVideoDuration, CMTimeMakeWithSeconds(transitionDuration, 600)), CMTimeMakeWithSeconds(transitionDuration, 600))];
    }
    else{
        int previousTransitionNumber = [[videoTransitionsArray objectAtIndex:i - 1] intValue];
        float previousTransitionDuration = [[videoTransitionsDurationArray objectAtIndex:i - 1] floatValue];

        if(i < videoAssetsArray.count - 1){
            [layerInstruction setOpacityRampFromStartOpacity:1.0 toEndOpacity:1.0 timeRange:CMTimeRangeMake(videoStartTime, CMTimeMakeWithSeconds(previousTransitionDuration, 600))];

            [layerInstruction setOpacityRampFromStartOpacity:1.0 toEndOpacity:0.0 timeRange:CMTimeRangeMake(CMTimeAdd(videoStartTime, CMTimeSubtract(currentVideoDuration, CMTimeMakeWithSeconds(transitionDuration, 600))), CMTimeMakeWithSeconds(transitionDuration, 600))];
        }
        else{
            [layerInstruction setOpacityRampFromStartOpacity:1.0 toEndOpacity:1.0 timeRange:CMTimeRangeMake(videoStartTime, CMTimeMakeWithSeconds(previousTransitionDuration, 600))];
        }
    }

    [instructionsArray addObject:layerInstruction];

    if(i < videoAssetsArray.count - 1){
        //TAKING INTO ACCOUNT THE TRANSITION DURATION TO OVERLAP VIDEOS
        videoStartTime = CMTimeAdd(videoStartTime, CMTimeSubtract(currentVideoDuration, CMTimeMakeWithSeconds(transitionDuration, 600)));
    }
    else{
        //TRANSITION NOT APPLIED TO THE END OF THE LAST CLIP
        videoStartTime = CMTimeAdd(videoStartTime, currentVideoDuration);
    }
}

mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero,videoStartTime);
mainInstruction.layerInstructions = instructionsArray;

AVMutableVideoComposition *videoComposition = [AVMutableVideoComposition videoComposition];
videoComposition.instructions = [NSArray arrayWithObjects:mainInstruction,nil];
videoComposition.frameDuration = CMTimeMake(1, 30);
videoComposition.renderSize = CGSizeMake(1920, 1080);

NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *videoOutputPath = [documentsDirectory stringByAppendingPathComponent:@"videoRecordingFinalOutput.mov"];
NSURL *videoOutputURL = [[NSURL alloc] initFileURLWithPath:videoOutputPath];

AVAssetExportSession *videoExportSession = [[AVAssetExportSession alloc] initWithAsset:mutableComposition presetName:AVAssetExportPresetHighestQuality];
videoExportSession.outputURL = videoOutputURL;
videoExportSession.videoComposition = videoComposition;
videoExportSession.outputFileType = AVFileTypeQuickTimeMovie;

[videoExportSession exportAsynchronouslyWithCompletionHandler:^{
    NSLog(@"EXPORT STATUS %ld %@", (long)videoExportSession.status, videoExportSession.error);

    if(videoExportSession.error == NULL){
        NSLog(@"EXPORT SUCCESSFUL");

        [library writeVideoAtPathToSavedPhotosAlbum:videoOutputURL
                                    completionBlock:^(NSURL *assetURL, NSError *error) {
                                        if(error) {

                                            NSError *error = nil;
                                            if([[NSFileManager defaultManager] fileExistsAtPath:videoOutputPath]){
                                                [[NSFileManager defaultManager] removeItemAtPath:videoOutputPath error:&error];
                                                if(error){
                                                    NSLog(@"VIDEO FILE DELETE FAILED");
                                                }
                                                else{
                                                    NSLog(@"VIDEO FILE DELETED");
                                                }
                                            }
                                        }
                                        else{
                                            NSError *error = nil;
                                            if([[NSFileManager defaultManager] fileExistsAtPath:videoOutputPath]){
                                                [[NSFileManager defaultManager] removeItemAtPath:videoOutputPath error:&error];
                                                if(error){
                                                    NSLog(@"VIDEO FILE DELETE FAILED");
                                                }
                                                else{
                                                    NSLog(@"VIDEO FILE DELETED");
                                                }
                                            }
                                        }
                                    }];
    }
    else{
        NSError *error = nil;
        if([[NSFileManager defaultManager] fileExistsAtPath:videoOutputPath]){
            [[NSFileManager defaultManager] removeItemAtPath:videoOutputPath error:&error];
            if(error){
                NSLog(@"VIDEO FILE DELETE FAILED");
            }
            else{
                NSLog(@"VIDEO FILE DELETED");
            }
        }
    }
}];
}

Answer 1

与其为每个剪辑创建新的 videoTracks，不如尝试仅使用 2 个 videoTracks 并在这 2 个中插入 timeRanges。并在 2 个轨道之间进行过渡

所以第一个视频将被插入到 videoTrack1 中，第二个视频将被插入到 videoTrack2 中，这样就可以应用过渡，然后再次将第三个剪辑插入到轨道 1 中，依此类推。