Using scripts to automatically fit video
Let's start with a shape tag. I have copied this from the built-in, and modified the resolution:
<TranscodePresetDocument
xmlns="http://xml.vidispine.com/schema/vidispine">
<name>my-shape-tag</name>
<format>mp4</format>
<audio>
<codec>aac</codec>
<bitrate>128000</bitrate>
<channel>0</channel>
<channel>1</channel>
<stream>2</stream>
</audio>
<video>
<scaling>
<width>500</width>
<height>200</height>
<pixelAspectRatio>
<horizontal>1</horizontal>
<vertical>1</vertical>
</pixelAspectRatio>
</scaling>
<codec>h264</codec>
<bitrate>2000000</bitrate>
<framerate>
<numerator>1</numerator>
<denominator>25</denominator>
</framerate>
<preset>high</preset>
</video>
</TranscodePresetDocument>
I then added a script:
var inWidth = shape.getVideoComponent().get(0).getResolution().getWidth(); // http://apidoc.vidispine.com/latest/xsddocs/com/vidispine/generated/VideoComponentType.html
var inHeight = shape.getVideoComponent().get(0).getResolution().getHeight();
var scaling = preset.getVideo().getScaling();
var outWidth = scaling.getWidth();
var outHeight = scaling.getHeight();
var targetDAR = new com.vidispine.generated.AspectRatioType();
scaling.setTargetDAR(targetDAR);
targetDAR.setHorizontal(outWidth);
targetDAR.setVertical(outHeight);
var proportionalDifference = outHeight * inWidth–outWidth * inHeight;
if (proportionalDifference > 0) { // output is taller (skinnier) than input
padding = -proportionalDifference / outWidth;
scaling.setTop(padding / 2);
scaling.setBottom(padding - padding / 2);
} else { // output is fatter than input
padding = proportionalDifference / outHeight;
scaling.setLeft(padding / 2);
scaling.setRight(padding - padding / 2);
}
The order of how Vidispine applies the commands in the scaling tag is:
Crop/pad
Rotate
Scale
So, we are comparing the proportions and either pad top/bottom or left/right. Remember that setTop/Bottom/Left/Right refers to cropping values: negative values mean padding.
The original (scaled):
The result (scaled):