I am trying to take a different approach at combining videos. I am creating a new track for each transformation.
The problem with this code is that the first video is shown and all others are black.
The audio overlay is correct for the entire segment. It looks like the video is not brought in to the composition because the size of the file is 5 M when it should be about 25M. The 5M size correlates to the size of the first clip and the audio track. All of the AVAssets appear to be valid. The files do exist on the file system. Here is the code:
- (void)mergeVideos:(NSMutableArray *)assets withCompletion:(void (^)(NSString *))completion; {
// NSMutableArray *instructions = [NSMutableArray new];
CGSize size = CGSizeZero;
CMTime currentstarttime = kCMTimeZero;
int tracknumber = 1;
int32_t commontimescale = 600;
CMTime time = kCMTimeZero;
AVMutableComposition *mutableComposition = [AVMutableComposition composition];
NSMutableArray *instructions = [[NSMutableArray alloc] init];
for (NSURL *assetUrl in assets) {
AVAsset *asset = [AVAsset assetWithURL:assetUrl];
NSLog(@"Number of tracks: %lu Incremental track number %i", (unsigned long)[[asset tracks] count], tracknumber);
// make sure the timescales are correct for these tracks
CMTime cliptime = CMTimeConvertScale(asset.duration, commontimescale, kCMTimeRoundingMethod_QuickTime);
AVMutableCompositionTrack *videoCompositionTrack = [mutableComposition addMutableTrackWithMediaType:AVMediaTypeVideo
preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *assetTrack = [asset tracksWithMediaType:AVMediaTypeVideo].firstObject;
NSLog(@"Running time: value = %lld timescale = %d", time.value, time.timescale);
NSLog(@"Asset length: value = %lld timescale = %d", asset.duration.value, asset.duration.timescale);
NSLog(@"Converted Scale: value = %lld timescale = %d", cliptime.value, cliptime.timescale);
NSError *error;
[videoCompositionTrack insertEmptyTimeRange:CMTimeRangeMake(kCMTimeZero, time)];
[videoCompositionTrack insertTimeRange:CMTimeRangeMake(time, cliptime)
ofTrack:assetTrack
atTime:time
error:&error];
if (error) {
NSLog(@"Error - %@", error.debugDescription);
}
// this flips the video temporarily for the front facing camera
AVMutableVideoCompositionLayerInstruction *inst = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoCompositionTrack];
// set the flipping trasform to the correct tracks
if ((tracknumber == 2) || (tracknumber == 4) || (tracknumber == 6) || (tracknumber == 8) || (tracknumber == 10)) {
CGAffineTransform transform = CGAffineTransformMakeRotation(M_PI);
[inst setTransform:transform atTime:time];
} else {
CGAffineTransform transform = assetTrack.preferredTransform;
[inst setTransform:transform atTime:time];
}
// don't block the other videos with your black - needs to be the incremental time
[inst setOpacity:0.0 atTime:time];
// add the instructions to the overall array
[instructions addObject:inst];
// increment the total time after w use it for this iteration
time = CMTimeAdd(time, cliptime);
if (CGSizeEqualToSize(size, CGSizeZero)) {
size = [asset tracksWithMediaType:AVMediaTypeVideo].firstObject.naturalSize;;
}
// incrememt the track counter
tracknumber++;
}
AVMutableVideoCompositionInstruction *mainVideoCompositionInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
mainVideoCompositionInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, time);
mainVideoCompositionInstruction.layerInstructions = instructions;
// bring all of the video together in the main composition
AVMutableVideoComposition *mainVideoComposition = [AVMutableVideoComposition videoComposition];
mainVideoComposition.instructions = [NSArray arrayWithObject:mainVideoCompositionInstruction];
// setup the audio
AVMutableCompositionTrack *audioCompositionTrack = [mutableComposition addMutableTrackWithMediaType:AVMediaTypeAudio
preferredTrackID:kCMPersistentTrackID_Invalid];
// Grab the path, make sure to add it to your project!
NSURL *soundURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"bink-bink-lexus-3" ofType:@"aif"]];
AVURLAsset *soundAsset = [AVURLAsset assetWithURL:soundURL];
NSError *error;
// add audio to the entire track
[audioCompositionTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, mutableComposition.duration)
ofTrack:[soundAsset tracksWithMediaType:AVMediaTypeAudio][0]
atTime:kCMTimeZero
error:&error];
// Set the frame duration to an appropriate value (i.e. 30 frames per second for video).
// mainVideoComposition.frameDuration = CMTimeMake(1, 30);
mainVideoComposition.renderSize = size;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths firstObject];
int number = arc4random_uniform(10000);
self.outputFile = [documentsDirectory stringByAppendingFormat:@"/export_%i.mov",number];
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mutableComposition
presetName:AVAssetExportPreset1280x720];
exporter.outputURL = [NSURL fileURLWithPath:self.outputFile];
//Set the output file type
exporter.outputFileType = AVFileTypeQuickTimeMovie;
exporter.shouldOptimizeForNetworkUse = YES;
dispatch_group_t group = dispatch_group_create();
dispatch_group_enter(group);
[exporter exportAsynchronouslyWithCompletionHandler:^{
dispatch_group_leave(group);
}];
dispatch_group_notify(group, dispatch_get_main_queue(), ^{
NSLog(@"Export File (Final) - %@", self.outputFile);
completion(self.outputFile);
});
}
