mmcv/video/optflow.py
def flowwrite(flow, filename, quantize=False, concat_axis=0, *args, **kwargs):
    """Write optical flow to file.

    If the flow is not quantized, it will be saved as a .flo file losslessly,
    otherwise a jpeg image which is lossy but of much smaller size. (dx and dy
    will be concatenated horizontally into a single image if quantize is True.)

    Args:
        flow (ndarray): (h, w, 2) array of optical flow.
        filename (str): Output filepath.
        quantize (bool): Whether to quantize the flow and save it to 2 jpeg
            images. If set to True, remaining args will be passed to
            :func:`quantize_flow`.
        concat_axis (int): The axis that dx and dy are concatenated,
            can be either 0 or 1. Ignored if quantize is False.
    """
    if not quantize:
        with open(filename, 'wb') as f:
            f.write('PIEH'.encode('utf-8'))
            np.array([flow.shape[1], flow.shape[0]], dtype=np.int32).tofile(f)
            flow = flow.astype(np.float32)
            flow.tofile(f)
            f.flush()
    else:
        assert concat_axis in [0, 1]
        dx, dy = quantize_flow(flow, *args, **kwargs)
        dxdy = np.concatenate((dx, dy), axis=concat_axis)
        imwrite(dxdy, filename)
def flowwrite(flow, filename, quantize=False, concat_axis=0, *args, **kwargs):
    """Write optical flow to file.

    If the flow is not quantized, it will be saved as a .flo file losslessly,
    otherwise a jpeg image which is lossy but of much smaller size. (dx and dy
    will be concatenated horizontally into a single image if quantize is True.)

    Args:
        flow (ndarray): (h, w, 2) array of optical flow.
        filename (str): Output filepath.
        quantize (bool): Whether to quantize the flow and save it to 2 jpeg
            images. If set to True, remaining args will be passed to
            :func:`quantize_flow`.
        concat_axis (int): The axis that dx and dy are concatenated,
            can be either 0 or 1. Ignored if quantize is False.
    """
    if not quantize:
        with open(filename, 'wb') as f:
            f.write('PIEH'.encode('utf-8'))
            np.array([flow.shape[1], flow.shape[0]], dtype=np.int32).tofile(f)
            flow = flow.astype(np.float32)
            flow.tofile(f)
            f.flush()
    else:
        assert concat_axis in [0, 1]
        dx, dy = quantize_flow(flow, *args, **kwargs)
        dxdy = np.concatenate((dx, dy), axis=concat_axis)
        imwrite(dxdy, filename)
Write optical flow to file.

    If the flow is not quantized, it will be saved as a .flo file losslessly,
    otherwise a jpeg image which is lossy but of much smaller size. (dx and dy
    will be concatenated horizontally into a single image if quantize is True.)

    Args:
        flow (ndarray): (h, w, 2) array of optical flow.
        filename (str): Output filepath.
        quantize (bool): Whether to quantize the flow and save it to 2 jpeg
            images. If set to True, remaining args will be passed to
            :func:`quantize_flow`.
        concat_axis (int): The axis that dx and dy are concatenated,
            can be either 0 or 1. Ignored if quantize is False.