def grayscale(images):
    """
    Get the grayscale for the input images. The channels of images should be
    in order BGR.
    Args:
        images (tensor): the input images for getting grayscale. Dimension is
            `num frames` x `channel` x `height` x `width`.
    Returns:
        img_gray (tensor): blended images, the dimension is
            `num frames` x `channel` x `height` x `width`.
    """
    # R -> 0.299, G -> 0.587, B -> 0.114.
    img_gray = torch.tensor(images)
    gray_channel = (
        0.299 * images[:, 2] + 0.587 * images[:, 1] + 0.114 * images[:, 0]
    )
    img_gray[:, 0] = gray_channel
    img_gray[:, 1] = gray_channel
    img_gray[:, 2] = gray_channel
    return img_gray
Get the grayscale for the input images. The channels of images should be
in order BGR.
Args:
images (tensor): the input images for getting grayscale. Dimension is
`num frames` x `channel` x `height` x `width`.
Returns:
img_gray (tensor): blended images, the dimension is
`num frames` x `channel` x `height` x `width`.
videomamba/video_sm/datasets/video_transforms.py