AVVideoScalingModeKey doesn't work as expected

[gontovnik]

Hello,

First of all, thank you for building and supporting this library. It saved me a significant amount of time.

Unfortunately, lately, I discovered the following issue – when I try to export the landscape video as a portrait video with the AVVideoScalingModeResizeAspectFill, it correctly crops the video horizontally, but doesn't scale it vertically. Please see the images attached below.

Original video (portrait):

Original video (landscape):

The result of compression:

The expected result of compression:

The configuration used:

let compression = [
  AVVideoAverageBitRateKey: NSNumber(integerLiteral: 1500000),
  AVVideoProfileLevelKey: AVVideoProfileLevelH264BaselineAutoLevel as String
] as [String: Any]
exporter.videoOutputConfiguration = [
  AVVideoCodecKey: AVVideoCodecType.h264,
  AVVideoWidthKey: NSNumber(integerLiteral: 720),
  AVVideoHeightKey: NSNumber(integerLiteral: 1280),
  AVVideoScalingModeKey: AVVideoScalingModeResizeAspectFill,
  AVVideoCompressionPropertiesKey: compression
]

Has anyone faced this issue or does a know a way around it?

Thank you!

[sjmueller]

We have the same exact problem! Hoping a fix comes soon, the library has been excellent otherwise.

[piemonte]

The library had custom "centering logic" that always used min(xRatio, yRatio), which is aspect-fit behavior. This completely ignored the user's AVVideoScalingModeKey setting, causing videos to have black bars instead of filling the target dimensions.

Added scaling mode detection:

• Checks if user specified AVVideoScalingModeKey
• ResizeAspectFill: Uses max(xRatio, yRatio) to fill entire frame (may crop)
• Resize: Stretches to exact dimensions with non-uniform scaling
• Default/ResizeAspect: Uses legacy min(xRatio, yRatio) for backward compatibility

Key changes:
if scalingMode == AVVideoScalingModeResizeAspectFill {
videoComposition.renderSize = targetSize // Use target, not source size
ratio = max(xRatio, yRatio) // Fill frame (was min)
} else if scalingMode == AVVideoScalingModeResize {
matrix = matrix.scaledBy(x: xRatio, y: yRatio) // Stretch to exact dimensions
} else {
// Legacy behavior for backward compatibility
ratio = min(xRatio, yRatio)
}