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Diffstat (limited to 'files/docs/rotation.md')
| -rw-r--r-- | files/docs/rotation.md | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/files/docs/rotation.md b/files/docs/rotation.md index fb84fce5..a08430fd 100644 --- a/files/docs/rotation.md +++ b/files/docs/rotation.md @@ -100,4 +100,8 @@ Inverting can be achieved with almost any libyuv function by passing a negative I420Mirror and ARGBMirror can also be used to rotate by 180 degrees by passing a negative height. +# Cropping - Vertical Flip +When cropping from a subsampled format like NV21, the method of setting the start pointers wont work for odd crop start y on the UV plane. +If the height after cropping will be odd, invert the source - point to the last row, negate the strides, and pass negative height, which +will re-invert the image as the conversion outputs. |