Render glitches in Fusion - and constant crashes

Hi everybody... I´m sorry if this was covered somewhere else, but my english is not as good as that I would find the right words to describe this glitch apparently...

I am compositing in Fusion with mp4 clips from a SOny A7SIII. And besides crashing every other 10 minutes i get these very strange render glitches:

Screenshot 2021-06-19 at 12.51.37.jpg (108.84 KiB) Viewed 524 times

they apear every other frame, sometimes all frames - and they are moving. im talking about the transparent lines ...

I use a delta key and a 3D camera to place the clips inside a camera movement.

you have any idea? im on the latest 17.2.1 Build 12

thanks so much!!

Describe your hardware in detail and your resolution.

oh yes, sure

- its a macbook pro 16" 2019 with AMD Radeon Pro 5500M 4 GB; 2,3 GHz 8-Core Intel Core i9 & 16 GB 2667 MHz DDR4; running MacOS 10.15.7

and the material is 4K

i know, the machine is way to underpowered - but these renderissues should not happen ... i get the crashes maybe when ram is full - but also this should be handled differently ... or am i wrong?

thanks!!

One thing I would try is Transcoding the H.264 originals into a more robust codec like ProRes and using that for editing.

It is underpowered for 4K. But if you are trying to render into H.264, try ProRes for output instead.

i transcoded everything into prores and also the output is prores, but i still get these glitches on 17.3.1 build 5...

in final output... cleared all render cache ... but still
they are also consistent even if i render just that one frame-what to do?

thanks

So you did transcode your sources too? If so, what’s your timeline resolution?
If it’s in UHD, try HD.
You might still be overwhelming your GPU.

even rendering just one single frame? and all frames before and after are ok?

yes its UHD and i did transcode all sources.

its like this with proxies as well ... so i guess there is something in the composition or somewhere else ... i cant find the answer. on the fusion page going through the timeline frame by frame its ok, going backwards frame by frame its there ...

very very weird behavior

Does it show in the source? It might be a recording glitch then.
Oh, and you could try to deactivate hardware support for rendering.

thanks for the tip with hardware - ill try that

no its not in the source - its in a fusion comp ...

Try an HD timeline if you didn't yet.