Correct parameters for rotation using $BitmapDecoder.GetSoftwareBitmapAsync - powershell

Question

I have this PowerShell code:
$AsyncTask = $BitmapDecoder.GetSoftwareBitmapAsync()
But discovered that some of the images coming in are rotated, so experimenting I came up with this:
$BmTf = [BitmapTransform]::new()
$BmTf.Rotation = [BitmapRotation]::None
# $BmTf.Rotation = [BitmapRotation]::Clockwise90Degrees
# $BmTf.Rotation = [BitmapRotation]::Clockwise180Degrees
# $BmTf.Rotation = [BitmapRotation]::Clockwise270Degrees
$AsyncTask = $BitmapDecoder.GetSoftwareBitmapAsync(
[BitmapPixelFormat]::Bgra8,
[BitmapAlphaMode]::Ignore,
$BmTf,
[ExifOrientationMode]::IgnoreExifOrientation,
[ColorManagementMode]::DoNotColorManage
)
While it does work, I'm not familiar BitmapPixelFormat, or the other parameters. The documentation for GetSoftwareBitmapAsync() doesn't appear to give any hints on what the default value it is using for BitmapPixelFormat.
Does anyone know the best values to pass to the version of GetSoftwareBitmapAsync() that takes 5 parameters to mimic the version of GetSoftwareBitmapAsync() that takes 0 parameters?
EDIT:
Just found out that trying [BitmapPixelFormat]::Unknown causes this error:
Exception calling "GetSoftwareBitmapAsync" with "5" argument(s): "The
parameter is incorrect. Windows.Graphics.Imaging: The bitmap pixel
format is unsupported."
But no errors with [BitmapPixelFormat]::Bgra8.

Answer 1

I don't know why GetSoftwareBitmapAsync doesn't like [BitmapPixelFormat]::Unknown, but here is the solution I found.
I need to first load the image to see if it needs rotating. That is done with the original command:
$AsyncTask = $BitmapDecoder.GetSoftwareBitmapAsync()
$SoftwareBitmap = GetAsync( $AsyncTask, ([SoftwareBitmap]) )
Then extract its BitmapPixelFormat:
$BitmapPixelFormat = $SoftwareBitmap.BitmapPixelFormat
And then use $BitmapPixelFormat for all calls to the 5 parameter version of GetSoftwareBitmapAsync().