A Flix Cloud user wrote us to ask about the new cropping tools. His background is in Adobe Premiere and he found himself getting very unexpected results in Flix Cloud. Cropping in Flix Cloud is done differently than most GUI video editing tools, so I thought I’d explain it here in some detail.
Cropping Specifies Boundaries, Not Pixel Subtraction
Cropping in Flix Cloud does not trim pixels away from the edges of the input video; rather, you define the boundaries of the area you want to retain after cropping. For example, if you enter 120 as the Crop Right value in a Recipe, Flix Cloud will not crop 120 pixels off the right side of the video. The application interprets it as “the right boundary of the crop area is 120 pixels away from the left edge of the input video.”
Think of the input video as a canvas. Imagine that you’re defining a bounding box on top of the canvas. It’s like the marquee select tools you see in graphics editors like Photoshop–you drag the marquee selector over the canvas to select objects in a defined region of the canvas.
The point of origin (0,0) for the bounding box is the top left corner of the video. All cropping values in Flix Cloud (top, bottom, left, right) are relative to the point of origin.
Example
Let’s say the content of your input videos is 720×400, but the videos have been letterboxed with black mattes on the top and bottom to make the actual dimensions 720×540 (e.g., for display on 4:3 aspect monitors). That’s 140 pixels of wasted space in every video frame. 16:9 aspect is becoming the norm today, and letterboxing is handled automatically by most video players, so you want to crop off the 70-pixel letterbox mattes to make the videos their true content size, 720×400. These would be your settings in Flix Cloud:
Crop Top: 70
Crop Bottom: 470
Crop Left: Leave blank
Crop Right: Leave blank
This creates a “selection box” that starts 70 pixels from the top left and extends down to 470 pixels from the top, effectively cropping 70 pixels from the top and 70 pixels from the bottom (540-70=470) of the video. Because we didn’t specify right and left values, they weren’t cropped.
Here’s an image to illustrate the crop area you would end up with:
Flix Cloud Crops Prior to Scaling
Pixels are cropped from the input video prior to any scaling operations in your Recipe. This means you’re always scaling the dimensions of the cropped video, not the input video.
Send Us Your Questions
As always, if you have any questions about Flix Cloud, write to us at support at flixcloud dot com.
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