add io and gui+fix2

data/1.OpenCV初阶/1.OpenCV基础/4.IO与GUI/video_read_write.md

@@ -8,7 +8,7 @@
 这是合影的效果：
 <object width="500" height="300" data="./birds_concat.mp4"></object>
 
-基本的实现代码如下：
+基本的实现代码如下，合影每10帧采样一次：
 
 ```python
 import numpy as np
@@ -20,6 +20,7 @@ if __name__ == '__main__':
     out = ...
     # TODO(You): 请在此正确创建待保存的目标mp4文件`out`
 
+    i = 0
     while(cap.isOpened()):
 
         ret, bird_frame = cap.read()
@@ -33,7 +34,9 @@ if __name__ == '__main__':
         )
 
         cv2.imshow('bird_concat_frame', bird_concat_frame)
-        out.write(bird_concat_frame)
+        if i % 10 == 0:
+            out.write(bird_concat_frame)
+        i += 1
         if cv2.waitKey(1) & 0xFF == ord('q'):
             break
 

data/1.OpenCV初阶/1.OpenCV基础/4.IO与GUI/video_read_write.py

@@ -15,6 +15,7 @@ if __name__ == '__main__':
         (width*2, height)
     )
 
+    i = 0
     while(cap.isOpened()):
 
         ret, bird_frame = cap.read()
@@ -28,7 +29,9 @@ if __name__ == '__main__':
         )
 
         cv2.imshow('bird_concat_frame', bird_concat_frame)
-        out.write(bird_concat_frame)
+        if i % 10 == 0:
+            out.write(bird_concat_frame)
+        i += 1
         if cv2.waitKey(1) & 0xFF == ord('q'):
             break