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• how to improve edge interpolation of rotation in moviepy

  15 juillet 2021, par OneWorld

  I tried changing the interpolation method of rotation from 'bilinear' to 'bicubic' in the below, but it didn't seem to improve the edge interpolation. (it still looks a little bit jagged)

  


  I was wondering what I need to do to improve this ?

  


  import moviepy.editor as mped
import sys
import numpy as np

bgrd_width = 200
bgrd_height = 200
sunset = mped.ImageClip("sunset200x100.jpg", duration=1).set_position((1, 1))
bgrd = mped.ColorClip(size=(bgrd_width, bgrd_height), color=np.array([200, 200, 200]).astype(np.uint8), duration=3).set_position((0, 0))

angle = 56
interpolation = 'bicubic'

rotated_sunset = sunset.add_mask().rotate(angle, unit='deg', expand=True, resample=interpolation).set_duration(3)
stacked_clips = mped.CompositeVideoClip([bgrd, rotated_sunset], size=[bgrd_width, bgrd_height])

stacked_clips.write_videofile(f'sunset_rotated_{angle}_{interpolation}.mp4', fps=5)



  


  See attached comparison image of bilinear and bicubic interpolation.


  


  Adding to this, I have seen now that the inside of the image does improve in quality with cubic, compared with nearest neighbour.

  


  

  


  The reason for the smooth inside, and jagged asset edge is because there's no pixel to sample from outside the boundary of the image, when interpolation is applied.

  


  I wrote some moviepy code, which adds a black margin (which actually turns transparent) and mask and then rotates. With bicubic interpolation it creates course, black lines, with a strange blend. However, with bilinear interpolation, the lines are much less apparent.

  


  # Add margin, add mask, rotate with interpolation of transparent 2 pixel border.
original_clip = mped.ImageClip("sunset200x100.jpg")
opaque_color = np.array([255, 255, 255]).astype(np.uint8)
margin_color = np.array([0, 0, 0]).astype(np.uint8)
margin_added_clip = original_clip.margin(2, color=margin_color)  # adds 2 pixel black border.
color_mask = mped.ColorClip(size=(original_clip.size), color=opaque_color).margin(2, color=margin_color)
mask = color_mask.to_mask()  # converts to grayscale with values between 0 and 1
masked_clip = margin_added_clip.set_mask(mask)  # adds the float mask to the clip
rotated_sunset = masked_clip.rotate(56, unit='deg', expand=True, resample="bicubic")
rotated_sunset.save_frame("sunset_rotated_56_degrees_moviepy_with_2px_mask.png")  # uses imageio to save the frame.


  


  

  


  However,

  


  If you switch from bicubic to bilinear, it looks a lot better :-

  


  

  


• OpenCV3 returning float FRAME_COUNT

  15 mars 2016, par mprat

  I am using OpenCV3 on OSX with Python 2.7 bindings. However, when I try to read the frame count of my video (a .mp4 video), it returns a float - I am expecting an int. Do I need to compile OpenCV3 with some special flags ? Am I missing some codecs ?

  import cv2
  
  vid = cv2.VideoCapture("vid.mp4")
  
  print vid.get(cv2.CAP_PROP_FRAME_WIDTH)

  And it returns a float.

  Installation details :

  • ffmpeg : brew install ffmpeg --with-dcadec --with-openh264 --with-openjpeg --with-openssl --with-tools --with-x265  --with-zimg --with-libvidstab --with-libvpx
  • opencv3 : brew install opencv3 --with-ffmpeg --with-contrib

• gst-inspect-1.0 do not see avdec_h264

  16 octobre 2020, par Marat Zakirov

  Previously I installed gstreamer via conda and its (good) plugins
next I installed gst-libav via sudo apt-get install gstreamer1.0-libav next I used apt-file list gstreamer1.0-libav to see installation path and found it to be /usr/lib/x86_64-linux-gnu/gstreamer-1.0/ next I read running gstream manual and then

  


  GST_PLUGIN_PATH=/usr/lib/x86_64-linux-gnu/gstreamer-1.0/ gst-inspect-1.0 avdec_h264

(base) marat@user-System-Product-Name:~$ ls -lh /usr/lib/x86_64-linux-gnu/gstreamer-1.0/ | grep av
-rw-r--r-- 1 root root 181K мар 21  2020 libgstavi.so
-rw-r--r-- 1 root root  56K мар 21  2020 libgstinterleave.so
-rw-r--r-- 1 root root 251K дек  9  2019 libgstlibav.so
-rw-r--r-- 1 root root  15K мар 21  2020 libgstnavigationtest.so
-rw-r--r-- 1 root root  40K мар 21  2020 libgstwavenc.so
-rw-r--r-- 1 root root  48K мар 21  2020 libgstwavpack.so
-rw-r--r-- 1 root root  72K мар 21  2020 libgstwavparse.so


  


  It found many new modules but didn't found avdec_h264. What I am missing ?

  


  UPDATE :

  


  I just want way to use gstreamer via conda virtenv python appliation. If you know valid way to do so I will consider your reply as answer.