AVAssetExportSession - Join 2 mp4 files in IOS - ios

Question

I am trying to join 2 preexisting mpeg4 video's together on an ipad2 with the following code.
-(void)mergeTestVideos
{
//setup asset
NSString *firstassetpath = [NSString stringWithFormat:#"%#mpeg4-1.mp4", NSTemporaryDirectory()];
NSString *secondassetpath = [NSString stringWithFormat:#"%#mpeg4-2.mp4", NSTemporaryDirectory()];
NSFileManager *fileManager = [NSFileManager defaultManager];
AVAsset *firstAsset = [AVAsset assetWithURL:[NSURL fileURLWithPath:firstassetpath]];
AVAsset *secondAsset = [AVAsset assetWithURL:[NSURL fileURLWithPath:secondassetpath]];
NSLog(#"FirstAsset Is Readable = %d", firstAsset.isReadable);
NSLog(#"FirstAsset Is playable = %d", firstAsset.isPlayable);
NSLog(#"FirstAsset Is exportable = %d", firstAsset.exportable);
NSLog(#"SecondAsset Is Readable = %d", secondAsset.isReadable);
NSLog(#"SecondAsset Is playable = %d", secondAsset.isPlayable);
NSLog(#"SecondAsset Is exportable = %d", secondAsset.exportable);
//setup composition and track
AVMutableComposition *composition = [[AVMutableComposition alloc]init];
AVMutableCompositionTrack *track = [composition addMutableTrackWithMediaType:AVAssetExportPresetPassthrough preferredTrackID:kCMPersistentTrackID_Invalid];
//add assets to track
[track insertTimeRange:CMTimeRangeMake(kCMTimeZero, firstAsset.duration) ofTrack:[[firstAsset tracksWithMediaType:AVMediaTypeVideo]objectAtIndex:0] atTime:kCMTimeZero error:nil];
[track insertTimeRange:CMTimeRangeMake(kCMTimeZero, secondAsset.duration) ofTrack:[[secondAsset tracksWithMediaType:AVMediaTypeVideo]objectAtIndex:0] atTime:firstAsset.duration error:nil];
// 5 - Create exporter
AVAssetExportSession *exporter = [[AVAssetExportSession alloc]initWithAsset:composition presetName:AVAssetExportPresetPassthrough];
NSString *outputURL = [NSString stringWithFormat:#"%#mergedvid.mp4", NSTemporaryDirectory()];
NSLog(#"%#", exporter.supportedFileTypes);
exporter.outputURL=[NSURL fileURLWithPath:outputURL];
exporter.outputFileType = AVFileTypeMPEG4;
[exporter exportAsynchronouslyWithCompletionHandler:^{
dispatch_async(dispatch_get_main_queue(), ^{
[self exportDidFinish:exporter];
});
}];
}
-(void)exportDidFinish:(AVAssetExportSession*)session {
NSLog(#"export method");
NSLog(#"%i", session.status);
NSLog(#"%#", session.error);
}
and output is as follows:
- FirstAsset Is Readable = 1
- FirstAsset Is playable = 1
- FirstAsset Is exportable = 1
- SecondAsset Is Readable = 1
- SecondAsset Is playable = 1
- SecondAsset Is exportable = 1
- (
"com.apple.quicktime-movie",
"com.apple.m4a-audio",
"public.mpeg-4",
"com.apple.m4v-video",
"public.3gpp",
"org.3gpp.adaptive-multi-rate-audio",
"com.microsoft.waveform-audio",
"public.aiff-audio",
"public.aifc-audio",
"com.apple.coreaudio-format"
)
-export method
- 4
- Error Domain=AVFoundationErrorDomain Code=-11838 "Operation Stopped" UserInfo=0x155f76f0 {NSLocalizedDescription=Operation Stopped, NSLocalizedFailureReason=The operation is not supported for this media.}
Ok so according to the output my files are ok and exportable and mp4 is a supported output type.
Does anybody have any idea why it is giving me the error 'The operation is not supported for this media'

Answer 1

I think this statement is your culprit
AVMutableCompositionTrack *track = [composition addMutableTrackWithMediaType:AVAssetExportPresetPassthrough preferredTrackID:kCMPersistentTrackID_Invalid];
Here you are passing AVAssetExportPresetPassthrough where you should have used AVMediaTypeVideo or AVMediaTypeAudio

Answer 2

If you are joining two videos then why you are using kCMTimeZero at both place while inserting time range. I think it should be
[track insertTimeRange:CMTimeRangeMake(kCMTimeZero, firstAsset.duration) ofTrack:[[firstAsset tracksWithMediaType:AVMediaTypeVideo]objectAtIndex:0] atTime:kCMTimeZero error:nil];
[track insertTimeRange:CMTimeRangeMake(kCMTimeZero, secondAsset.duration) ofTrack:[[secondAsset tracksWithMediaType:AVMediaTypeVideo]objectAtIndex:0] atTime:firstAsset.duration error:nil];
See changes in atTime while inserting time range for secondAsset