Video Edits on the Cheap 3

Figure 1: The use of the color curves to lower contrast level.

So the first couple pages of this blog post were pretty dry, and served only to put Blender in the mood to make video.  Once everything is set, I spend most of my time tweaking the color curves property box.  Typically, I find myself working mostly in the C and R tabs, to adjust contrast, brightness, and often to add a little red, since CMOS sensor based cameras are too fond of blue.

In figure 1, you see an “S curve” in the C color tab.  This kind of curve lowers contrast.  This can be seen by comparing the video in figure 1 with any of those on the two previous pages.  Why lower contrast?  Well, when videos are shot in low light, dark artifacts appear in the CMOS sensor rendered video.  Lowering the contrast makes these artifacts less noticeable.

Figure 2: More detail about the curve manipulations

In Figure 2, I’ve shown a little more detail about using the curves.  Note that I’m not well versed in this, and am mostly using the “play around with the curves until I like what I see method” – which has been a tad slow when editing a few of the more “challenging” videos. Is that over-saturation, over-exposure, or both on Hutch’s front leg?  In spite of my obvious novice level Blender-tise, I’ve been able to resurrect some videos that otherwise would have had a trash bin destiny. 

Figure 3: I’ve clicked on the red tab, to bring out the gold coat.

In figure 2, I’ve selected the red tab in the color curves sub section of the properties box, and pushed it up a little (it normally is a straight line from corner to corner).  The adjustment made Hutch’s real gold color come out, and stand up!

Figure 4: Gamma adjusted a touch

Figure 5:  Location of some pertinent items shown for color edit.

The red color adjustment tab is shown.  It seems that I have to adjust the red tab curve more often than the blue or green.  I think that this could have to do with camera sensors (in general) being more responsive to blue than to red.  I usually feel the need to bump the red value up a little bit.  This seems to make sense intuitively, if you think about LED bulbs.  They are (sort of) the opposite of camera sensors (they are designed to project light rather than receive it).  Early LED bulbs were always too blue IMO.   CMOS sensors are not the same as LED technology, but both things are made by certain processes in silicon.  So – probably there’s an answer in there somewhere for a physics geek.

Figure 6: Clicking the first icon (rather than the 3’rd from left) – brings us back to the render/animate panel subsection.

Clicking the first icon (rather than the 3’rd from the left) – takes us back to the render/animate panel subsection.  First, I make sure the green bar is at frame 1, click the render button to render the first frames to see that it’s what I want, and then click the animate button to start applying my color corrections over the whole movie. When the editor has done its work, it will deposit the output file into the video output directory (previously specified in properties).

Figure 7:  Output video file is shown in the output directory after a run.

Figure 4 shows a little floating terminal window that contains the file listing of the output file for the session.  It’s been automatically named 0001-9999.avi – where the “9999” is the frame count that I had specified in the properties panel.  Note that this may or may not be the actual frame count.  But, this naming scheme makes it easy to manipulate the video name without much fuss, and then later be able to figure out which session the file references.

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