Render cache so bad

Hi,

Just wanted to know if something will be done for the management of the render cache, because actually it sooo baddd !

So imagine you're using optical flow quite heavily, because it's good and simple. My computer isn't fast enough to play it realtime (gtx 1060 / 6 core oc ;-( ) so I activate the render cache to make my life easier, everything turn blue I can finally play my timeline. And now I see what the result I want to make some little adjustement. Moving clip arround. So I move a clip from one place to the other. And now the entire timeline need to be render .... !!!!!!!!!!!!! But why ? I didn't move speed of the clip, didn't cut them, I just move them to a different place, and not only it need to render the clip but the timeline again and again. How people can work this way ??

On premiere pro. You hit render, once your clip are rendered, you can move them arround without re render the all timeline !! And when you expend a clip you just need to render the new part of this clip. Why blackmagic couldn't work this way ? This things to re render the timeline every time will make me mad and make me quit this software I guess. Maybe I did something wrong, so I would happilly take advice, except upgrading my system... Thanks. And please blackmagic, make something... Seriously !

[Peter Chamberlain]

Which version of Resolve are you using?

On premiere pro. You hit render, once your clip are rendered, you can move them arround without re render the all timeline !! And when you expend a clip you just need to render the new part of this clip. Why blackmagic couldn't work this way ? This things to re render the timeline every time will make me mad and make me quit this software I guess. Maybe I did something wrong, so I would happilly take advice, except upgrading my system... Thanks. And please blackmagic, make something... Seriously !

Hi bebellm

There are several parameters that will affect performance on your system. Render Cache is only one of them.
And by itself, quite a complex tool.

Resolve caching (which is very different from rendering in premiere) can be tweaked to work at numerous levels of a clip either in smart (Resolve decides) or user (you decide) modes, it can affect a clips source, output, a specific node (and upstream from it), a group, OFX and more. Once you master the way it works, it becomes a powerful tool you'll miss in other software.

But Resolve also offers you Performance Mode (new), Proxy and Optimized Media. All of which can be used with Caching in endless combinations for peak performance.

Keep in mind that if you are working with processor intensive media (highly compressed, h264 variations, RAW) and not using Optimized Media, adding optical flow on top won't help.
OF is rarely (never) real time on any software... why not use Nearest till you're ready to output?

I don't know enough about your system.. but the 1060 is usually an ok card.. nothing more.

lastly, there are several more settings, tweaks and things to watch out for to get optimal performance

you can read about it and about caching in pages 110-124 in the manual (which Premiere doesn't have...)

I agree with you that there is something about rendering a clip to a baked file that stays that way regardless of (some) manipulations is useful, but that is not how caching in Resolve currently works (think more like AE than PP). Maybe having Resolve save its cache for anything that is moving/extending a clip in certain situations wouldn't be a bad feature to have someday.

Since you mentioned Premiere as an advantage in this aspect, I'll mention it too

Premiere has an automatic Caching system that creates 6 (!) different types of files automatically with most media types - there is a small list of codecs and containers that don't cache, lack of yellow line in timeline indicates no caching.
you have little control over this system (you can finally manage it a bit better since version 2017.1) except from cleaning after it.

Premier's Proxy/Transcode modes are each limited in their own way comparing to Resolve's, and offer much frustration to many workflows.

Lastly, Premier's render engine can be quite destructive. Most filters will downgrade the entire sequence to 8 bit even if placed on a single clip. without warning.

hector

Hi,

@Hector, thank you for the answer, here is mine.

I'm using Blackmagic Ursa footage.
- Yes GTX 1060 is ok not more. But don't want to invest in quad gtx 1080 ti to have a system working. -
- When premiere can do on this point what i want almost without graphic card.
- I don't see the difference between performance mode or not sorry.
- I don't see the difference to my demand with or withou optimized media, sorry.
- I read, I don't see more stuff to tweak to not have this problem, sorry.

I agree with you that there is something about rendering a clip to a baked file that stays that way regardless of (some) manipulations is useful, but that is not how caching in Resolve currently works (think more like AE than PP). Maybe having Resolve save its cache for anything that is moving/extending a clip in certain situations wouldn't be a bad feature to have someday.

=> Please blackmagic listen users

- I didn't understand the premiere pro part, it's maybe less good on the paper, but except the fact davinci can render without hitting "enter" as a user I find the cache more performant on premiere.

- It's not a problem if it's desctructive if it's fast for me.
- And yes I desactivated optical flow in project setting to work faster because it was just not possible to finish my work.

@Peter Chamberlain. Problem on all version until davinci resolve 14 beta 6. Thank you.

Mikaël

Hi,

@Hector, thank you for the answer, here is mine.

I'm using Blackmagic Ursa footage.
- Yes GTX 1060 is ok not more. But don't want to invest in quad gtx 1080 ti to have a system working. -
- When premiere can do on this point what i want almost without graphic card.
- I don't see the difference between performance mode or not sorry.
- I don't see the difference to my demand with or withou optimized media, sorry.
- I read, I don't see more stuff to tweak to not have this problem, sorry.

Hi Mikaël

Ursa footage is in RAW? in what resolution?
Optimized Media (like cache) is tweak-able in settings. You can choose what to optimize/cache to and what resolution. eventually you should see a difference.
Performance Mode is new so I still don't fully grasp it. but it will change based on all other parameters so to my understanding its dynamic.

Render time for OF in PP or Resolve is rather similar (OF is Not real time in PP) and many changes you'll do in PP will force you to re-render OF.

- It's not a problem if it's desctructive if it's fast for me.

Ok. But for most users of Resolve it is, and since Resolve operates in 32 bit constantly, some strain on performance is a price to pay.

hector.

- It's in Apple Prores.
- I don't see any difference. Still same problem. I use optimized media on a clip. If I move it arround in my timeline, it needs to be re render.
- Yes it needs render time in PP, but you don't need to re render, if you move it arround.
- In this case, strain on performance, it's just impossible to edit without waiting 5 minutes to re render. So yes only solution it's not use optical flow in the timeline. But it's the opposite goal of the render cache I guess...

Thanks.

I'm not as knowladgeable as Hector, but I think there may be something else going on here...because bebellm mentioned that his entire timeline needs to be cached again...

I am just finishing a big project and have used smart cache and clip output cache throughout the whole project. Every time when I changed a clip, only that clip needed re-caching...not the rest.

Now, at the end of the project I have added a logo overlay in a seperate video track on top of the footage, the logo overlay is one clip that spans the entire timeline... if I change anything in the timeline, no matter how small the adjustment is, my timeline needs to be re-cached completely.

This is very annoying, but I can understand why this happens. Do you perhaps have something similar in your timeline, and overlay on top ?

[Peter Chamberlain]

If you have a clip that spans the whole timeline and you turn that on/off or edit it, then you are affecting the whole timeline, thus recache. If however you are only changing the clips below, only those sections should be recaching.. we just checked it here on and didnt see your 'whole' timeline recache issue. So i guess more detail is needed to understand why. Can you post your DRP and let me know which clip you change which causes the whole timeline to recache?

This is very odd indeed, today I had no recaching issues, so I must have done something else that caused this.
I'll keep an eye on this and if it happens again, report back.

To the OP, please ignore my previous message, obviously I was mistaken.

I tried this in the beta.... With a setting of "user" (didn't test "smart"), all timeline clips with transitions and all clips with titles above them rendered automatically, which in this case meant that everything in this short test timeline was cached.

Moving a clip in the middle of the timeline to the end caused everything to the right of that clip's original position to re-render (including the moved clip). Same thing would occur if that clip was moved back to its original position -- everything to the right of its new position would re-render, including the moved clip.

EDIT: different editing procedures, with the same end result, have different effects on automatic cache-rendering. For example, dragging a clip from the middle of the timeline to the end forces a re-render of material from that mid-point to the end. Cutting and pasting it (as an overwrite) usually doesn't, though the moved clip is itself likely to re-render. But an insert paste will more likely result in a mass re-render, as will a drag move.

@Peter Chamberlain

Blue timeline :
http://imgur.com/a/1zaVy

Last clip from first place, red timeline :
http://imgur.com/a/ONoSH

Everything need to be re render again.

@Peter Chamberlain do you need more ?

I could go further also. For exemple if you cut in half a clip already render, or make it shorter, you shouldn't need to re render. And it's not the case. And if you extend a clip you should need to re render only the new part, not the all clip. Like premiere pro does.

@Peter Chamberlain What do you think ?

I was pretty excited when I saw that my problem was fixed in the 14.1 log. I download, and now it's worst on this point (congrat for the rest ). I let the computer do the render, I don't touch anything just watching and after one minute everything which was blue, become red again.

And when you move a clip which is blue yes it seem to stay blue if you move it arround that's nice, but it takes like 5 seconds to update the render color of the timeline .. I have a pretty short timeline ...

Hope everything will be perfect soon.

[Peter Chamberlain]

Do you have live save on?
If not, fobu have save with backup on?

Can you try live save?

Hi,

When you do color effect in the timeline mode (compare to the clip mode in the color tab) , it'snt taken in the render cache ? Am I missing something here ?

Hi,

When you do color effect in the timeline mode (compare to the clip mode in the color tab) , it'snt taken in the render cache ? Am I missing something here ?

Any update. Thanks