Yesterday I learned a few things about capturing video using Roxio Creator NXT Pro 3, and made a list of things to do that would simplify the process. The first item on that list was to set the capture area to a) something that works out to a 16×9 or 4×3 aspect ratio so there is no distortion during import or editing and b) dimensions that already match a standard output format. I chose a 640×480 resolution for a small demo program I wrote in Delphi (Pascal) when I first started working with induction melting furnaces.
Link to full resolution video here.
The video begins with the furnace already partially filled with molten metal, as indicated by the green line. It then shows several additions of unmelted material, which is of lower density than the molten metal and indicated by the light blue line, followed by the melting of that material and the subsequent rise in the level of molten metal. In reality the added material would partially sink (like and ice cube), but I didn’t include that behavior in the model. I also didn’t incorporate a thermodynamic model; the point here was just to give me a platform for visualization and a way to calculate the mass of metal still left in the furnace as it is tilted and pours out its contents. The latter part of the video shows the furnace being titled and pouring out its contents until empty, and then being returned to the vertical position.
Calculating the volume of material left in an open-topped cylinder is easy if the bottom surface is covered. If the bottom surface is not covered, however, unless exactly half of it is not covered, there are no direct formulas for calculating the volume of the resultant shape, which is known as an ungula. The volume instead, at least as far as I could determine from the references I had back when I wrote this, had to be calculated using a numerical integration technique. That’s a story for another day, though. Today I’m talking about video capture.
It turns out that setting a capture area as I described makes the entire process of importing, editing, and exporting work easily and without distortion of the video. Indeed, it was almost too easy. The details of this video were a bit less important than they were in yesterday’s example, so the embedded video looks decent even at half its normal size.