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  • L’utiliser, en parler, le critiquer

    10 avril 2011

    La première attitude à adopter est d’en parler, soit directement avec les personnes impliquées dans son développement, soit autour de vous pour convaincre de nouvelles personnes à l’utiliser.
    Plus la communauté sera nombreuse et plus les évolutions seront rapides ...
    Une liste de discussion est disponible pour tout échange entre utilisateurs.

  • Websites made ​​with MediaSPIP

    2 mai 2011, par

    This page lists some websites based on MediaSPIP.

  • Use, discuss, criticize

    13 avril 2011, par

    Talk to people directly involved in MediaSPIP’s development, or to people around you who could use MediaSPIP to share, enhance or develop their creative projects.
    The bigger the community, the more MediaSPIP’s potential will be explored and the faster the software will evolve.
    A discussion list is available for all exchanges between users.

Sur d’autres sites (10870)

  • ffmpeg difference when using -lavfi or -filter_complex

    25 mai 2020, par Luiz Cieslak

    I've started to use ffmpeg recently. I have been using only the -filter_complex flag to apply filters. I stumbled upon this SO question :

    



    FFmpeg : How to convert horizontal video 16:9 to vertical video 9:16, with blurred background on top and bottom sides

    



    A ffmpeg maintainer answers it using the -lavfi flag :

    



    ffmpeg -i input.mp4 -lavfi "[0:v]scale=iw:2*trunc(iw*16/18),boxblur=luma_radius=min(h\,w)/20:luma_power=1:chroma_radius=min(cw\,ch)/20:chroma_power=1[bg];[bg][0:v]overlay=(W-w)/2:(H-h)/2,setsar=1" output.mp4

    



    I tried to change -lavfi flag to -filter_complex :

    



    ffmpeg -i input.mp4 -filter_complex "[0:v]scale=iw:2*trunc(iw*16/18),boxblur=luma_radius=min(h\,w)/20:luma_power=1:chroma_radius=min(cw\,ch)/20:chroma_power=1[bg];[bg][0:v]overlay=(W-w)/2:(H-h)/2,setsar=1" output.mp4

    



    The result is the same and didn't notice a perf change.

    



    Is there a difference when using either flags ?

    


  • avfilter/vf_colorkey : fix formula for calculation of difference

    16 mai 2020, par Paul B Mahol
    avfilter/vf_colorkey : fix formula for calculation of difference

    Also fixes colorhold filtering.
    • [DH] libavfilter/vf_colorkey.c
    • [DH] tests/ref/fate/ffmpeg-filter_colorkey

  • Frame size difference before and after creating a video

    31 mars 2020, par tkhan

    I am creating a video from images using Opencv.

    



    dim=(width, height)
fourcc = cv2.VideoWriter_fourcc(*'X264')
out_d = cv2.VideoWriter(save_path_depth,fourcc, fps, dim)


    



    After creating video I read video and extract frames from that video

    



    while(cap.isOpened()):
    ret, frame = cap.read()

    if ret == False:
        break
    print(frame)
    cv2.imwrite(output+"/"+ str(i).zfill(1) + ".png", frame)      
    i+=1

cap.release()


    



    Frame size is almost double than size of frame i initially used to create the video. Other than that when i do frame to frame comparison, some frames are completely different than their counterpart original frames. Can somebody explain what can be the reason behind it.

    


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