Portrait Video plays in black screen - ios

Question

Update
Don't use simulator to test video translations. But I have codec issue
asked in another question here. Any help is appreciated.
I am using AVURLAsset to create my videos and they work fine as long the videos picked from gallery are in landscape mode. But when I use a portrait video it either plays in black screen(audio plays) or the frames are twisted (see image).
Update:
I tried using the CGAffineTransform still no luck.
Here's the code:
-(void) createVideo{
AVMutableComposition* mixComposition = [AVMutableComposition composition];
NSDictionary *options = #{AVURLAssetPreferPreciseDurationAndTimingKey:#YES};
_videoAsset = [[AVURLAsset alloc]initWithURL:video_url options:options];
CMTime startTimeV=CMTimeMakeWithSeconds(videoStartTime.floatValue, 1);
CMTime endTimeV=CMTimeMakeWithSeconds(videoEndTime.floatValue, 1);
CMTimeRange video_timeRange = CMTimeRangeMake(startTimeV,endTimeV);
AVMutableCompositionTrack *a_compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
[a_compositionVideoTrack insertTimeRange:video_timeRange ofTrack:[[_videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:kCMTimeZero error:nil];
AVMutableVideoCompositionInstruction *mainInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, self.videoAsset.duration);
AVMutableVideoCompositionLayerInstruction *videolayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:a_compositionVideoTrack];
AVAssetTrack *videoAssetTrack = [[self.videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
CGSize trackDimensions = {
.width = 0.0,
.height = 0.0,
};
trackDimensions = [videoAssetTrack naturalSize];
int width = trackDimensions.width;
int height = trackDimensions.height;
UIImageOrientation videoAssetOrientation_ = UIImageOrientationUp;
BOOL isVideoAssetPortrait_ = NO;
CGAffineTransform videoTransform = videoAssetTrack.preferredTransform;
if (videoTransform.a == 0 && videoTransform.b == 1.0 && videoTransform.c == -1.0 && videoTransform.d == 0) {
videoAssetOrientation_ = UIImageOrientationRight;
isVideoAssetPortrait_ = YES;
}
if (videoTransform.a == 0 && videoTransform.b == -1.0 && videoTransform.c == 1.0 && videoTransform.d == 0) {
videoAssetOrientation_ = UIImageOrientationLeft;
isVideoAssetPortrait_ = YES;
}
if (videoTransform.a == 1.0 && videoTransform.b == 0 && videoTransform.c == 0 && videoTransform.d == 1.0) {
videoAssetOrientation_ = UIImageOrientationUp;
}
if (videoTransform.a == -1.0 && videoTransform.b == 0 && videoTransform.c == 0 && videoTransform.d == -1.0) {
videoAssetOrientation_ = UIImageOrientationDown;
}
// CGAffineTransform transformToApply=CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(90.0));
[videolayerInstruction setTransform:videoAssetTrack.preferredTransform atTime:kCMTimeZero];
[videolayerInstruction setOpacity:0.0 atTime:self.videoAsset.duration];
mainInstruction.layerInstructions = [NSArray arrayWithObjects:videolayerInstruction,nil];
AVMutableVideoComposition *mainCompositionInst = [AVMutableVideoComposition videoComposition];
CGSize naturalSize;
if(isVideoAssetPortrait_){
naturalSize = CGSizeMake(videoAssetTrack.naturalSize.height, videoAssetTrack.naturalSize.width);
} else {
naturalSize = videoAssetTrack.naturalSize;
}
float renderWidth, renderHeight;
renderWidth = naturalSize.width;
renderHeight = naturalSize.height;
mainCompositionInst.renderSize = CGSizeMake(renderWidth, renderHeight);
mainCompositionInst.instructions = [NSArray arrayWithObject:mainInstruction];
mainCompositionInst.frameDuration = CMTimeMake(1, 30);
And the export :
-(void)export{
NSArray *dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docsDir = [dirPaths objectAtIndex:0];
NSString* fileName=[NSString stringWithFormat:#"myvideo%lld.mp4",[#(floor([[NSDate date] timeIntervalSince1970])) longLongValue]+1];
NSString *outputFilePath = [docsDir stringByAppendingPathComponent:[NSString stringWithFormat:#"%#",fileName]];
NSURL *outputFileUrl = [NSURL fileURLWithPath:outputFilePath];
if ([[NSFileManager defaultManager] fileExistsAtPath:outputFilePath])
[[NSFileManager defaultManager] removeItemAtPath:outputFilePath error:nil];
AVAssetExportSession* _assetExport = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];
_assetExport.outputFileType = AVFileTypeMPEG4;
_assetExport.outputURL = outputFileUrl;
_assetExport.videoComposition = mainCompositionInst;
ShareViewController *newViewController = [self.storyboard instantiateViewControllerWithIdentifier:#"vidShare"];
[_assetExport exportAsynchronouslyWithCompletionHandler:
^(void ) {
dispatch_async(dispatch_get_main_queue(), ^{
newViewController.videoFilePath=outputFileUrl;
[self.navigationController pushViewController:newViewController animated:YES];
});
}
];
}
Landscape = OK
Portrait = FAIL

Answer 1

I've had this issue before. Set videolayerInstruction's transform using videoAssetTrack.preferredTransform works in most cases. But sometimes preferredTransform may lack of value of tx(ty) (you should check CGAffineTransform In Apple API Reference if you don't know what is tx(ty)) or tx(ty) has inaccurate value which results in wrong video positioning(such as playing in black screen).
So the point is: you should use preferredTransform to determine the origin video orientation and make the transform of your own.
here is the code of getting the orientation of track:
- (UIInterfaceOrientation)orientationForTrack:(AVAsset *)asset {
UIInterfaceOrientation orientation = UIInterfaceOrientationPortrait;
NSArray *tracks = [asset tracksWithMediaType:AVMediaTypeVideo];
if([tracks count] > 0) {
AVAssetTrack *videoTrack = [tracks objectAtIndex:0];
CGAffineTransform t = videoTrack.preferredTransform;
// Portrait
if(t.a == 0 && t.b == 1.0 && t.c == -1.0 && t.d == 0) {
orientation = UIInterfaceOrientationPortrait;
}
// PortraitUpsideDown
if(t.a == 0 && t.b == -1.0 && t.c == 1.0 && t.d == 0) {
orientation = UIInterfaceOrientationPortraitUpsideDown;
}
// LandscapeRight
if(t.a == 1.0 && t.b == 0 && t.c == 0 && t.d == 1.0) {
orientation = UIInterfaceOrientationLandscapeRight;
}
// LandscapeLeft
if(t.a == -1.0 && t.b == 0 && t.c == 0 && t.d == -1.0) {
orientation = UIInterfaceOrientationLandscapeLeft;
}
}
return orientation;
}
And code for getting the needed transform to apply to the videolayerInstruction's transform:
- (CGAffineTransform)transformBasedOnAsset:(AVAsset *)asset {
UIInterfaceOrientation orientation = [AVUtilities orientationForTrack:asset];
AVAssetTrack *assetTrack = [asset tracksWithMediaType:AVMediaTypeVideo][0];
CGSize naturalSize = assetTrack.naturalSize;
CGAffineTransform finalTranform;
switch (orientation) {
case UIInterfaceOrientationLandscapeLeft:
finalTranform = CGAffineTransformMake(-1, 0, 0, -1, naturalSize.width, naturalSize.height);
break;
case UIInterfaceOrientationLandscapeRight:
finalTranform = CGAffineTransformMake(1, 0, 0, 1, 0, 0);
break;
case UIInterfaceOrientationPortrait:
finalTranform = CGAffineTransformMake(0, 1, -1, 0, naturalSize.height, 0);
break;
case UIInterfaceOrientationPortraitUpsideDown:
finalTranform = CGAffineTransformMake(0, -1, 1, 0, 0, naturalSize.width);
break;
default:
break;
}
return finalTranform;
}
Hope it works for you.