FCPX 10.4.6 There are some elements of the timeline which are not rendering frames resulting in jittery playback

UPDATE:

Hi - thought I would come back and reply to this thread in case anyone finds it. I actually solved my own issue after about 6 hours of trial and error. Turns out that its not the 'rendering' as such - its the joys of Optical Flow vs Frame Blend (and rendering I guess). In some of the transitions, the Video Quality was set to Optical Flow - this was checked but still the white dots stayed but when I tried to render it still said nothing to do basically. In the end after a lot of searching and experimenting, I found that it was as simple as selecting the clip(s) involved - then using the Modify->Video Quality and clicking Optical Flow again (even though it is already checked). Boom! it starts chugging through and regenerates all the frames needed - and then a quick re-render and all the dots disappear. A few minutes later and the video is perfect - no dots.

In case you also wonder, I tried deleting the rendered files and manually deleting the Optical Flow files - but this didnt work - only as I described which is basically selecting again Optical Flow worked. I tried it on two other projects and it works faultlessly.

Thanks Tom for responding so quickly and when I went looking for the info you asked for I got sidetracked but ended up finding the result - so thank you for that and helping me persevere :)

Regards

Chris

Hi Tom,

stupid of me but I am not at teh machine until Friday so will only really be able to share the exact details then with screenshots if possible. I am not 100% sure of the graphics - whatever the mac mini has - there is over 500GB free on the SSD and it was restored from Time Machine so assume the formatting is whatever is standard in Mojave?

There is one main clip about 13 mins long and I have overlayed some pan shots as the person on the main clip is talking using a short cross-fade effect to move to the pan and back to the long clip. so there is never more than two clips stacked if that makes sense (and yes you can tell I am a complete novice!). Then there are about 5 titles overlayed with info about links etc - they simpy fade in and then out again. Some are over the single main clip and some above the double clips.

When I cleared the generated files, re-rendering takes about 3-4 mins max but it just seems to skip certain bits so it leaves sections of the white dots - some above the fade and text where you might expect work to be being done and some just above the main clip itself on its own. the clips are in 1080p 60fps and the project is set to 1080p 30fps.

This is only happening on the last three Events/Projects I have created and these are since I updated to 10.4.6 - everything prior to that has been working perfectly with no issues at all - same camera - same types of clips, same formats etc.

Sorry for the lengthy text and no actual stats but I have checked every single clip to make sure that there isnt any real difference in the formats etc than I had before.