Caching still has a lot of bugs

I just don't get how Resolve's cache has all these weird bugs after all these years. There are things I saw in whatever version was in 2019, which prevented me from jumping from Premiere at the time. Because I've never seen any NLE that creates artifacts around text or images with alpha, and it's something I saw today with text. I didn't save stills from that but I bet many of you saw them from time to time, and they are random, because they happen only sometimes. I saw this earlier today and I installed Beta 3 yesterday.

But there are other bugs. I noticed that if I put a timeline inside other timeline, and I change anything in the source timeline, that won't delete the cache in the parent one. And sometimes it will do just weird stuff, like this example.

This is the middle of an edge wipe transition in a timeline:

Cache bug render in original timeline.jpg (482.13 KiB) Viewed 612 times

This is the same, but on a parent timeline. Notice the hard line instead of the feathered one:

Cache bug render in 4k timeline.jpg (875.72 KiB) Viewed 612 times

So I select the clip, which would be the original timeline, or call it compound clip if you wish, and I go to the menu to delete the cache just for the selection. No change.

Then I disable caching, setting it to none. It shows me the feathered line:

Cache bug render in 4k timeline no cache.jpg (930.31 KiB) Viewed 612 times

But what happens if I choose to delete the cache for the selection, then enable caching again and set it to Smart? Back to the hard line:

Cache bug render in 4k timeline.jpg (875.72 KiB) Viewed 612 times

So what's the only choice? To delete the whole cache for the whole project. So about 20 minutes of rendering have to go, because it's not enough to delete the cache for the selection, you have to delete the whole project cache.

Does this sound like the way previewing a timeline should be in a modern NLE?

Unfortunately nested timelines have been buggy for years and BMD hasn’t seen this as enough of a priority to address it. They don’t tell us these things so we only know this by seeing that they haven’t fixed them even though people have been talking about these issues for years.

Yeah, you've come across the fundamental difference between Adobe's approach to catching and Resolve.

Adobe programs render a timeline level, flattened cache of the timeline. Resolve caches every layer separately. This includes alpha channels.

BM has a couple of issues because of this. The first is that nested sequence have an order of operations problem. To solve that... Well you can't. Best you can do is turn on Smart caching and pre cache the nested timeline and then step out to the main one. It solves it...90% of the time.

The second issue that they're going to come up against is that they've now promoted using the timeline as a place to do motion graphics. There's no way they can real time 15 layers from Photoshop so they'll have to do a timeline level cache to solve playback.

Maybe they are transferring their caching to a non layer based system? If they do that, it would solve the nested timeline issue as well as the motion graphics issue by creating flattened timeline caches.

Unfortunately nested timelines have been buggy for years and BMD hasn’t seen this as enough of a priority to address it. They don’t tell us these things so we only know this by seeing that they haven’t fixed them even though people have been talking about these issues for years.

Well, I just had a few instances of this happening in the original timeline, not nested. The only difference is that in the original timeline, if I delete the cache for just the selected clips, then when it rebuilds the cache, it works. If it was nested it doesn't delete the children cache.

Yeah, you've come across the fundamental difference between Adobe's approach to catching and Resolve.

Adobe programs render a timeline level, flattened cache of the timeline. Resolve caches every layer separately. This includes alpha channels.

BM has a couple of issues because of this. The first is that nested sequence have an order of operations problem. To solve that... Well you can't. Best you can do is turn on Smart caching and pre cache the nested timeline and then step out to the main one. It solves it...90% of the time.

The second issue that they're going to come up against is that they've now promoted using the timeline as a place to do motion graphics. There's no way they can real time 15 layers from Photoshop so they'll have to do a timeline level cache to solve playback.

Maybe they are transferring their caching to a non layer based system? If they do that, it would solve the nested timeline issue as well as the motion graphics issue by creating flattened timeline caches.

Layered cache has its uses, but it's ridiculous that Resolve doesn't have a simple flat everything cache.

As horribly buggy as Adobe software is, I remember crashes, but not weird stuff like this:

Cache bug render in original timeline with text alpha garbage.jpg (797.29 KiB) Viewed 309 times

Cache bug render in original timeline with text alpha garbage 2.jpg (409.53 KiB) Viewed 309 times

These two BTW, are in the original timeline, and not even screenshots, I did an export to still from Resolve Studio itself.

This is bizarre stuff I remember seeing when I started using Resolve at 18.6 and it's still there. This is not user error, because when you wipe the cache and it renders the same thing again, it does it correctly.

I think BMD has to take a look at how the cache gets corrupted that it will display garbage around borders of text, or around borders in videos and stills with alpha channel.

Are you doing this on the timeline or in Fusion. If you're comping your plates in Fusion but adding the text on the timeline you are probably getting extra Alpha info above 1.0. In Fusion, use a Color Inspector and check out what your Alpha channel reads. If it's above 1.0 add a Brightness Contrast node and clip your black and whites right before your MediaOut.

If you want to be dead certain that your cache is going to be read correctly. Add a Boolean right before your MediaOut node with just a connection to the Orange input. Then Right-Click and cache and lock it. Now you'll have a guaranteed flattened comp that will read on the timeline as fast as an image sequence would.

The final blast you can do is to delete your MediaOut and make a new one. This will force the Timeline to recache no matter what.

I wouldn't comp on the timeline ever since you need to linearize your plates and tweak coloring anyways. It's best to make your beauty in Fusion. I don't know if you're using AGx or ACES or straight linear but keep your Color Info viewer on so you can check your Booleans along the way to make sure they don't double up Alpha channel info when doing your passes.

Are you doing this on the timeline or in Fusion.

The text is just Resolve Studio 20 beta 3. But it doesn’t matter, if it was user error, it would render all that garbage every single time, even after I delete the whole project’s cache.

In every single NLE and video software I ever used, like After Effects and Apple Motion, I’ve never the text becoming garbage like this. It’s obvious that BMD has to determine what is causing things like this and fix them already. Like I said, I saw this type of cache corruption back in Resolve 18.6.