Omar Mohammad wrote:I’m testing speed ramping by adding an adjustment clip and then in fusion I add Optical flow + Vector motion blur, without altering default settings.
I have Render Cache set to Smart, the blue line shows it’s been cached, but when I want to see the affect it skips the clip. To see the effect I have to render/deliver that part.
Is it possible my machine is unable to handle fusion?
Optical flow operations are very computationally intensive and are not meant to be used in real time with smooth playback. For that the best way is to export your optical flow node data with saver node into EXR format with vectors enabled and use a loader to import it into your flow, and than you will be able to see real time playback in Fusion.
In the edit page if its on an adjustment clip you can right click on the clip and choose render in place command to render it out for real time playback.
But of course you won't be able to change optical flow settings without rendering again. You can also right click on the optical flow node and choose cache to disk, but its going to eat up lot of hard drive. Sometimes its easier to simply either use a saver node and render it out in Jpeg or something for preview, along with the motion blur and if you like the results, leave for final render. Or you can just render it the way you have to see the results.
You can speed up some of the process by using ROI Region of Interest and just try to render a portion of the screen in fusion to see results. You can also try to use proxy settings which will on the fly show you reduced resolution in draft mode, which is not for preview of details, but mostly motion. So maybe choose proxy 4x or something for preview. You can activate the proxy mode in Fusion page if you are in resolve by right clicking bellow timeline and choosing proxy. And you can choose how much you want proxy to be, by right clicking at the very beginning of timeline in fusion page, and you will see a drop down menu with proxy options, 1,2,3,4,5 etc.
If you find that optical flow is too slow, consider rendering it out into OpenEXR files using a Saver node If the footage input flickers on a frame-by-frame basis, it is a good idea to deflicker the footage beforehand.
Trimming a Loader or MediaIn to only the range you need prevents analyzing unnecessary frames. When analyzing Optical Flow vectors, consider adding a Smooth Motion node afterward with smoothing for forward/ backward vectors enabled. The Smooth Motion node smooths various AOV (Arbitrary Output Variables) channels in a clip using optical flow to look at neighboring frames. It can be used for smoothing the Disparity channel in a stereo 3D clip, where it helps reduce temporal edge/fringing artifacts, but it can also smooth a wide range of channels like vectors, normals, and Z.
You can use two or more Smooth Motion nodes in sequence to get additional smoothing. With one Smooth Motion node, the previous, current, and next frames are examined for a total of 3; with two Smooth Motion nodes, 5 frames are examined; and with three Smooth Motion nodes, 7 frames are examined.
I often use Smooth Motion node with optical flow, to reduce any artifacts and in some cases its not really that much of a difference, and in others it makes a noticeable difference. So think about using it, if you need to, but its extra processing. A tradeoff between speed and quality.
The vector channels should use a float16 or float32 color depth, to provide + and – values.
Thu May 09, 2024 9:01 pm
