Disk Cache - Node performace

I have a flow where i'm network disk caching a merge (a greenscreen key) before it get's fed into it's background and lightwrap. The network disk caching works as expected when pre-rendering, and get a folder of RAW images for the merge node that was rendered from all the machines dedicated on the Render Manager. When trying to play back the node that was just cached (write the disk cache into memory) I get around 1 fps. However, if I go to the disk cache location for that node, and import that RAW cache as a loader and play back the loader into RAM I get around 17fps.

I've tried locking the disk cache and locking the branches, but not getting anywhere. The cache itself takes about 3 sec/frame, so when playing back the disk cache from the node, when the disk cache is enabled is shorter than actually re-processing the frames. Just not sure why I can't get the 17fps playback like I can when importing the cache directly.

Any thoughts?

Same problem here... Fusion Studio 8 beta 3

I think that's been the case for a while now, including pre Blackmagic.

You can always choose by showing cache dialogue and different format than RAW. If you are working in 16bit linear for example, you could write EXR or Tiff.

My personal choice is always to render pre-comps and add a loader. Keeps things a bit more visible on the flow as well.

If you don't use the disk cache, is it still 1fps?

One thing to remember is that the disk cache will only save out what's in the frame. If your comp downstream is modifying the DoD, then your disk cache will not be enough and you'll have to re-render. That's half bad, half good. It's slower than using Savers and Loaders, but it always works.

I haven't used any DOD in my comps, and I still can get slightly better performance when using the locked disk cache.... the difference between 1fps when fusion is rendering and 3fps when trying to read from the disk cache.

I'm with Rony, I've adopted my workflow to using the preRender disk cache option and then just adding the disk cache as a loader. Once one frame is cached, I load the preRender as a loader, and continue working down the flow, if you don't use you're local workstation as part of the farm, you still get really good performance, and once the preRender is finished you just reload the frames and you have your entire disk cache in your loader. It's a bit more manual than just being able to click the disk Cache button, but it does work quite well.

As long as we're on the topic, is there a way to make a "switch" node where you could toggle between the cached loader and the live flow? Potential allowing for A/B comparison?

That's normally done directly in the viewers using the buffers. If you're talking doing interactive adjustments downstream, then it's going to be re-rendering every time you want to switch, which may or may not be acceptable. Doing an interactive update preview might be the better option, it's more work to set up, but it's pretty cool, you get to see the footage running full speed at least.

But as for an actual tool, there's a Fuse for that. Stefan Ihringer has one called Switch that works well and can be adapted to any special situation you might need.

Thanks Chad, i'll look into the Fuse.

is there list of tools that don't need to re-render the entire flow... so you could disk cache what you need and then iterate after it's been cached.

The example being, if you preview a CC node and then make changes, it updates much quicker than it's first preview. Not sure if this is even a thing, but I seam to make iterative changes in the CC without having to re-render the entire flow every time.

Any time you're requesting a ROI that you don't have cached, it's going to need to render that. But if you have that larger ROI cached, then it's fine, so it should only need to do it once (unless you change the ROI again).