Add type hints in several files (#1999)

* Add typehint in such files

* Update mmcv/video/processing.py
Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>

* Fix np.ndarray str

* Fix

* Update mmcv/video/processing.py
Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>

* Fix

* Fix

* Update mmcv/video/processing.py
Co-authored-by: Jiazhen Wang <47851024+teamwong111@users.noreply.github.com>
Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>
Co-authored-by: Jiazhen Wang <47851024+teamwong111@users.noreply.github.com>

mmcv/device/mlu/_functions.py

 # Copyright (c) OpenMMLab. All rights reserved.
+from typing import List, Union
+
 import torch
 
 
-def scatter(input, devices):
+def scatter(input: Union[List, torch.Tensor], devices: List) -> List:
     """scatter copies tensor to MLU directly."""
     if isinstance(input, list):
         outputs = [scatter(_input, devices) for _input in input]

mmcv/image/colorspace.py

 # Copyright (c) OpenMMLab. All rights reserved.
+from typing import Callable, Union
+
 import cv2
 import numpy as np
 
 
-def imconvert(img, src, dst):
+def imconvert(img: np.ndarray, src: str, dst: str) -> np.ndarray:
     """Convert an image from the src colorspace to dst colorspace.
 
     Args:
@@ -19,7 +21,7 @@ def imconvert(img, src, dst):
     return out_img
 
 
-def bgr2gray(img, keepdim=False):
+def bgr2gray(img: np.ndarray, keepdim: bool = False) -> np.ndarray:
     """Convert a BGR image to grayscale image.
 
     Args:
@@ -36,7 +38,7 @@ def bgr2gray(img, keepdim=False):
     return out_img
 
 
-def rgb2gray(img, keepdim=False):
+def rgb2gray(img: np.ndarray, keepdim: bool = False) -> np.ndarray:
     """Convert a RGB image to grayscale image.
 
     Args:
@@ -53,7 +55,7 @@ def rgb2gray(img, keepdim=False):
     return out_img
 
 
-def gray2bgr(img):
+def gray2bgr(img: np.ndarray) -> np.ndarray:
     """Convert a grayscale image to BGR image.
 
     Args:
@@ -67,7 +69,7 @@ def gray2bgr(img):
     return out_img
 
 
-def gray2rgb(img):
+def gray2rgb(img: np.ndarray) -> np.ndarray:
     """Convert a grayscale image to RGB image.
 
     Args:
@@ -81,7 +83,7 @@ def gray2rgb(img):
     return out_img
 
 
-def _convert_input_type_range(img):
+def _convert_input_type_range(img: np.ndarray) -> np.ndarray:
     """Convert the type and range of the input image.
 
     It converts the input image to np.float32 type and range of [0, 1].
@@ -109,7 +111,8 @@ def _convert_input_type_range(img):
     return img
 
 
-def _convert_output_type_range(img, dst_type):
+def _convert_output_type_range(
+        img: np.ndarray, dst_type: Union[np.uint8, np.float32]) -> np.ndarray:
     """Convert the type and range of the image according to dst_type.
 
     It converts the image to desired type and range. If `dst_type` is np.uint8,
@@ -140,7 +143,7 @@ def _convert_output_type_range(img, dst_type):
     return img.astype(dst_type)
 
 
-def rgb2ycbcr(img, y_only=False):
+def rgb2ycbcr(img: np.ndarray, y_only: bool = False) -> np.ndarray:
     """Convert a RGB image to YCbCr image.
 
     This function produces the same results as Matlab's `rgb2ycbcr` function.
@@ -174,7 +177,7 @@ def rgb2ycbcr(img, y_only=False):
     return out_img
 
 
-def bgr2ycbcr(img, y_only=False):
+def bgr2ycbcr(img: np.ndarray, y_only: bool = False) -> np.ndarray:
     """Convert a BGR image to YCbCr image.
 
     The bgr version of rgb2ycbcr.
@@ -208,7 +211,7 @@ def bgr2ycbcr(img, y_only=False):
     return out_img
 
 
-def ycbcr2rgb(img):
+def ycbcr2rgb(img: np.ndarray) -> np.ndarray:
     """Convert a YCbCr image to RGB image.
 
     This function produces the same results as Matlab's ycbcr2rgb function.
@@ -240,7 +243,7 @@ def ycbcr2rgb(img):
     return out_img
 
 
-def ycbcr2bgr(img):
+def ycbcr2bgr(img: np.ndarray) -> np.ndarray:
     """Convert a YCbCr image to BGR image.
 
     The bgr version of ycbcr2rgb.
@@ -272,11 +275,11 @@ def ycbcr2bgr(img):
     return out_img
 
 
-def convert_color_factory(src, dst):
+def convert_color_factory(src: str, dst: str) -> Callable:
 
     code = getattr(cv2, f'COLOR_{src.upper()}2{dst.upper()}')
 
-    def convert_color(img):
+    def convert_color(img: np.ndarray) -> np.ndarray:
         out_img = cv2.cvtColor(img, code)
         return out_img
 

mmcv/onnx/info.py

@@ -5,7 +5,7 @@ import warnings
 import torch
 
 
-def is_custom_op_loaded():
+def is_custom_op_loaded() -> bool:
 
     # Following strings of text style are from colorama package
     bright_style, reset_style = '\x1b[1m', '\x1b[0m'

mmcv/video/processing.py

@@ -3,16 +3,17 @@ import os
 import os.path as osp
 import subprocess
 import tempfile
+from typing import List, Optional, Union
 
 from mmcv.utils import requires_executable
 
 
 @requires_executable('ffmpeg')
-def convert_video(in_file,
-                  out_file,
-                  print_cmd=False,
-                  pre_options='',
-                  **kwargs):
+def convert_video(in_file: str,
+                  out_file: str,
+                  print_cmd: bool = False,
+                  pre_options: str = '',
+                  **kwargs) -> None:
     """Convert a video with ffmpeg.
 
     This provides a general api to ffmpeg, the executed command is::
@@ -52,13 +53,13 @@ def convert_video(in_file,
 
 
 @requires_executable('ffmpeg')
-def resize_video(in_file,
-                 out_file,
-                 size=None,
-                 ratio=None,
-                 keep_ar=False,
-                 log_level='info',
-                 print_cmd=False):
+def resize_video(in_file: str,
+                 out_file: str,
+                 size: Optional[tuple] = None,
+                 ratio: Union[tuple, float, None] = None,
+                 keep_ar: bool = False,
+                 log_level: str = 'info',
+                 print_cmd: bool = False) -> None:
     """Resize a video.
 
     Args:
@@ -90,14 +91,14 @@ def resize_video(in_file,
 
 
 @requires_executable('ffmpeg')
-def cut_video(in_file,
-              out_file,
-              start=None,
-              end=None,
-              vcodec=None,
-              acodec=None,
-              log_level='info',
-              print_cmd=False):
+def cut_video(in_file: str,
+              out_file: str,
+              start: Optional[float] = None,
+              end: Optional[float] = None,
+              vcodec: Optional[str] = None,
+              acodec: Optional[str] = None,
+              log_level: str = 'info',
+              print_cmd: bool = False) -> None:
     """Cut a clip from a video.
 
     Args:
@@ -116,21 +117,21 @@ def cut_video(in_file,
     if acodec is None:
         options['acodec'] = 'copy'
     if start:
-        options['ss'] = start
+        options['ss'] = start  # type: ignore
     else:
         start = 0
     if end:
-        options['t'] = end - start
+        options['t'] = end - start  # type: ignore
     convert_video(in_file, out_file, print_cmd, **options)
 
 
 @requires_executable('ffmpeg')
-def concat_video(video_list,
-                 out_file,
-                 vcodec=None,
-                 acodec=None,
-                 log_level='info',
-                 print_cmd=False):
+def concat_video(video_list: List,
+                 out_file: str,
+                 vcodec: Optional[str] = None,
+                 acodec: Optional[str] = None,
+                 log_level: str = 'info',
+                 print_cmd: bool = False) -> None:
     """Concatenate multiple videos into a single one.
 
     Args: