Multithreading w/CVMetalTextureCacheCreateTextureFromImage

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Created Oct ’18

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In my MTKView render loop, I'm implementing a triple-buffering scheme which transitions between two videos (so, dual triple-buffering). This is done with a dispatch_semaphore_create(3);
As the CVPixelBuffer frames are arriving from my pair of AVPlayers, I convert them to MTLTextures with CVMetalTextureCacheCreateTextureFromImage.

I'm currently including the underlying CVMetalTextureCacheRef cache to the transitional buffers. So, there are 6 such caches that i rotate through.

Is this necessary? Overkill?

Is a call to CVMetalTextureCacheCreateTextureFromImage thread-safe? If not, a thought I had was to enclose the call to itin a dispatch_sync handler and grab the resulting texture, and have only one such cache on the MTKView.

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Answer 1

kerfuffle OP

Oct ’18

I generally use just a single metal cache object and always grab the textures from the cache on the video reading thread. The images have a lifetime of 1 second by default (I think), so if you're holding on to the texture for less than that, you should be OK.

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Answer 2

B_Payan OP

Oct ’18

Thanks. I've implemented only one cache on the view, rather than stringing along rotating caches.

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