AVVideoCompositionCoreAnimationTool with Core Animation layer as track input

Question

adriaan OP

Created Jul ’15

Replies 2

Boosts 0

Views 1.4k

Participants 3

I am using a

AVVideoCoreAnimationTool

to render titles on top of a video composition.

I used to use

+videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:inLayer:

to instantiate the animation tool.

However, I now need to use a custom compositor to render the video composition. I want to use

videoCompositionCoreAnimationToolWithAdditionalLayer:asTrackID:

so that I have access to an asset track with the titles in my compositor.

However, I can't get titles to render when adding the core animation layer as a track.

In my custom compositor I have access to the track, i.e. I can get a pixelBuffer for the trackID I have assigned for the Core Animation layer when instantiating the animation tool. But these pixel buffers are empty.

- (void)startVideoCompositionRequest:(AVAsynchronousVideoCompositionRequest *)request
{
     CMPersistentTrackID titleTrackID = ...
     CVPixelBufferRef titlePixelBuffer = [request sourceFrameByTrackID:titleTrackID];
     //titlePixelBuffer is valid pixel buffer but never contains any pixel data
}

When I set up the core animation tool the same way, but don't use a custom compositor, the title layer also isn't rendered.

If I set up the animation tool using

+videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:inLayer:

and don't use a custom compositor the title layer is rendered as it should.

Is there anything I'm missing?

(I am also adding the sourceTrackID of the title track to the composition's AVVideoCompositionInstruction instances)

Boost

Answer 1

sarperdag OP

Sep ’15

I was able to get this to work with the code below:

-(AVVideoCompositionCoreAnimationTool *) createAnimationToolForSize:(CGSize) size {
  
    CATextLayer *titleLayer = [CATextLayer layer];
    titleLayer.string = @"Text goes here";
    titleLayer.font = (__bridge CFTypeRef)(@"Helvetica");
    titleLayer.fontSize = size.height / 20;
    titleLayer.cornerRadius = size.height / 50;
    titleLayer.foregroundColor = [UIColor blackColor].CGColor;
    titleLayer.backgroundColor = [UIColor whiteColor].CGColor;
    titleLayer.frame = CGRectMake(size.width/4, size.height/4, size.width/2, size.height/2 );
    titleLayer.opacity = .5;   
    return [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithAdditionalLayer:titleLayer asTrackID:5];
}

_videoComposition.animationTool = [self createAnimationToolForSize:CGSizeMake(1280, 720)];

In my customcompositorclass, I correctly get the pixel buffers from that track and can display the text.

0

Answer 2

BigWorld_Zhu OP

Jun ’21

I have meet problem same with your correctly, Have you solved this problem? Any help will be appreciate very much.

0