Here is the step by step tutorial on how to extract the alpha’s using Fusion by Da Vinci Resolve.
NOTE! This is not the only way of extracting alpha’s and not all elements in our library are set up to extract it this way but this setup covers about 90% of the extraction process for our VFX Stock Footage.
This setup is just our recommendations as we created ideal lighting and sets to film each element. By using this process we stay as true as possible to every pixel for your composite.
Step 1
Make sure to denoise the element first. We do that by pressing Shift+Space -then write "remove noise" - press Add to create the "RemoveNoise" node. In the Remove Noise node press lock to simplify the options then visually remove the noise by striking a balance between "softness" and "detail."
Step 2
Duplicate the footage and remove the noise chain. Add a "TimeSpeed" node to one of the chains. Change the "speed" to 0.0 in order to create a frame hold on the first frame.
Step 3
Now we want to extract the difference between the framehold and all the other frames by using the Difference keyer. Call up a "DifferenceKeyer" node and connect the two footage chains to the keyer. This will create an alpha of the element. The values for the low and high will be around 0.01 and 0.05 but play around with the values for each element to finesse the pixels for the alpha channel.
Step 4
Duplicate the footage once more and use the difference keyer as a mask for the original footage. Create a Merge node and use the blue connection to ensure it is being treated as a mask. The result of the merge node and then be composited over anything else. (NOTE that this is just one of many methodologies at this point)
