1.5 Workbench Overview
In the previous extended study material for the Level 1 PFClean training (1.4 Workflow Manager) we looked at the organisational hub of PFClean, the Workflow Manager. We also added a number of nodes to the tree, one of those nodes is the Workbench which we shall be taking a look at in this follow up. The Workbench provides access to PFClean’s in depth per clip, manual and automatic restoration effects. Let’s start where we left off in the Workflow Manager.
If you haven’t completed the previous tutorial (1.4 Workflow Manager) I would suggest going back and starting from there as we will be using some of the material and profiles we generated.
NOTE: To follow along in this tutorial, you will need access to the clips provided for the class. If you don’t have them to hand, below you will find the link to download the footage again.
01. Preparing Clips for the Workbench
To enter the Workbench double click on the Workbench node in the Workflow Manager. When you first open the Workbench, you will see the panel at the bottom, showing the current Worklist containing clips in the node. In our case we only have a single clip here that we have flowed from Media bin 1, let’s play the clip through. You may have noticed this particular .dpx sequence has a number of shots contained within it. Due to the per clip nature of the Workbench we will want to cut this .dpx sequence into clips before we can begin work on them.
The purpose of the Cut tool is to split a large clip up into a number of smaller sub-clips. This serves two main purposes. Firstly to make the clip more manageable, especially if you are for example importing a whole reel of film as a single clip. Secondly certain clean up operations in the Workbench, in particular the optical flow used for dirt/dust/scratch detection, require there to be no edits in the clip being processed.
NOTE: Optical flow compares the differences between adjacent frames and if there is an edit in the clip being processed, such that adjacent frames do not relate to the same scene, then the calculations can produce invalid results.
Let’s now go ahead and cut our clips up. We will be using a combination of auto shot detection and manually inserting a cut point. By clicking the Detect button in the lower part of the GUI we will see a Progress bar appear showing us PFClean analysing the footage for cut points. When this is complete the shots it has detected will appear as a list in the central panel. Nothing has been committed at this stage and we still have an opportunity to go in and refine the detection. We can see blue markers have also been added to the timeline showing where the cut points are. Clicking on shots in the list will take us directly to that cut point.
At frame 68 you may have noticed another shot that has not been detected. There are two ways we can add this cut point in. The first way is to lower the Min. Length slider on the right hand side as this particular clip is less than 24 frames long, if you find PFClean is not detecting all of your shots you could also lower the detection Threshold slider and see PFClean dynamically update the clip list. The second way is to manually insert the cut point by going to the first frame of the shot and clicking Insert. This will add the cut point to the list. Once you have clicked the insert you may have noticed the button change to Remove, any cuts in the list can be removed by clicking Remove. Now that we have cut or our clips we are going to commit the cuts to the Media bin 1. We can do this by clicking on the button Commit All and Yes to confirm. Our four new clips will now appear inside Media bin 1.
NOTE: PFClean is only symbolically cutting the footage inside of the software and is not modifying the original source.
02. Building an Effects Stack
We can now see our four Full Aperture 2K clips in the Worklist. The first clip in the Worklist is automatically loaded into the Stack Manager and the Cinema when you enter the Workbench. You can work on a different clip by clicking its thumbnail in the Worklist.
Let’s play through the clip to evaluate the defects we are dealing with. The clip suffers from some very obvious sparkle, slight flickering as well as some instability. The Workbench provides a range of effects to address different film and video issues. We will have to select the effects suitable for tackling the defects in the clip.
Before we start working with the effects, we are going to set up a region of interest (ROI), to exclude the blanking on sides of the clip. Switch to the Workbench parameters and click the ROI button to the left of the clip preview to open the ROI panel.
Adjust the left side of the ROI, shown as a dotted rectangle in the Cinema, by simply dragging it into position. Then click the ROI button again to close the panel. Setting the ROI will reduce the amount of processing PFClean has to do.
It’s time to create the first effect. Click the button on the left edge of the Stack Manager to open a menu which lists all available effects. Find the Auto Stabilize effect under the image operations and select it from the menu.
You will see the Auto Stabilize effect created as the first, top-most, effect in our stack and the bottom panel will change to show the effect’s parameters. To find out more about how to use the Auto Stabilize effect and its parameters, click the button on the left of the effect’s UI to open the effect’s help page in your web browser. The Auto Stabilize effect is automatic and constantly running, for this exercise we won’t need to adjust any of the settings.
Let’s Play through the clip to review the result. The A/B split button provides an easy way to compare the result with the original clip. Simply drag the line along at the rectangle to move it across the frame. Then click the A/B button again to view the cleaned frame.
Next we are going to address the slight flicker in the clip. Click the + button again and select Auto De-Flicker from the menu under the image operations. This has created a second effect below the Auto Stabilize. The order of processing is top to bottom and the Auto De-Flicker effect will work on the result of the Auto Stabilize. The active effect is the one that is shown in the Cinema and is highlighted in white.
You can change the active effect, by clicking on this round button next to it , or by using the cursor up and down keys on your keyboard. This will allow you to edit the parameters and controls for that specific effect; the Cinema will show the results of everything down to the active effect in the stack.
You can delete the active effect by clicking and confirming on the trashcan below the + button, but we are not going to do this right now.
Let’s adjust a few settings in the Auto De-Flicker. The first thing we are going to adjust is the Range slider. The Range control specifies how many frames on either side of the current frame will be used to smooth out brightness fluctuations when correcting high-frequency flicker. The default value is 3, which corresponds to using 3 preceding frames and 3 following frames. Let’s increase this value to 5 by clicking and dragging the slider up. The next thing we are going to modify is the Block Size. The Block Size control specifies the spatial resolution for correcting high-frequency flicker that varies spatially throughout each frame (the block size is measured in pixels). Let’s reduce this down to around 22.
The last effect we are going to add to our stack is Dustbust. Let’s click the + button again next to the stack and find the Dustbust effect under Repair Operations. Again this is an automatic effect and will start working as soon as it is added to the stack every time you advance a frame all three effects are processed. This seems to have removed all the dust on the frame we are currently on so let’s leave the settings at default for now.
Click the playblast button to cache the clip in memory for real time review of the fixes so far and use the A/B button to see the before and after. Click the button again or press the Escape key to return to the Workbench.
03. Fixing the Second Clip
It is now time to look at the second clip. Click the button next to the clip preview to jump to the next clip. Upon reviewing the clip, we notice that it suffers from similar defects like the clip we have just worked on. In this case, we can re-use the stack and effects parameters we have just created.
This opens a dialog to let you pick the elements to include in the copied stack. We want to include the effects Auto Stabilize and Dustbust and also the Region Of Interest we have defined, so make sure everything is checked other than Auto De-Flicker, then click Copy. This will open the worklist overlay at the top of the Cinema. Select the second clip, then click Paste. All the effects have now automatically been applied to the new clip.
Use Playblast to review the fixes in the second clip.
04. Storing Presets
Effects stacks can also be stored more permanently as a preset. Click the button to display the Worklist panel, then click the Save button in the Workbench presets panel to store the current stack as a preset. These presets can be used in other Workbench nodes in the project, or exported to other projects.
05. Using Presets
To later apply a previously stored preset to all clips in the current worklist select the preset in the Workbench presets panel and click Apply All.