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Autres articles (29)

  • Encoding and processing into web-friendly formats

    13 avril 2011, par

    MediaSPIP automatically converts uploaded files to internet-compatible formats.
    Video files are encoded in MP4, Ogv and WebM (supported by HTML5) and MP4 (supported by Flash).
    Audio files are encoded in MP3 and Ogg (supported by HTML5) and MP3 (supported by Flash).
    Where possible, text is analyzed in order to retrieve the data needed for search engine detection, and then exported as a series of image files.
    All uploaded files are stored online in their original format, so you can (...)

  • HTML5 audio and video support

    13 avril 2011, par

    MediaSPIP uses HTML5 video and audio tags to play multimedia files, taking advantage of the latest W3C innovations supported by modern browsers.
    The MediaSPIP player used has been created specifically for MediaSPIP and can be easily adapted to fit in with a specific theme.
    For older browsers the Flowplayer flash fallback is used.
    MediaSPIP allows for media playback on major mobile platforms with the above (...)

  • De l’upload à la vidéo finale [version standalone]

    31 janvier 2010, par

    Le chemin d’un document audio ou vidéo dans SPIPMotion est divisé en trois étapes distinctes.
    Upload et récupération d’informations de la vidéo source
    Dans un premier temps, il est nécessaire de créer un article SPIP et de lui joindre le document vidéo "source".
    Au moment où ce document est joint à l’article, deux actions supplémentaires au comportement normal sont exécutées : La récupération des informations techniques des flux audio et video du fichier ; La génération d’une vignette : extraction d’une (...)

Sur d’autres sites (2071)

  • Read part of every frame of a video file

    18 novembre 2012, par user1414470

    I'm doing some tracking on video files. First I separate frames using ffmpeg and the for each frame i apply a mask and then perform the tracking algorithm.

    To make this process faster I'm thinking about reading only the parts I need. like reading the part that I apply the mask or better than that reading boxes around the previous positions of objects. So I'm looking for a way to decode and read a specific part of a specific frame from a video file. Is there any way to do that ?

  • FFmpeg dnn_processing with tensorflow backend : difficulties applying a filter on an image

    9 avril 2023, par ArnoBen

    I am trying to perform a video segmentation for background blurring similar to Google Meet or Zoom using FFmpeg, and I'm not very familiar with it.

    


    Google's MediaPipe model is available as a tensorflow .pb file here (using download_hhxwww.sh).

    


    I can load it in python and it works as expected, though I do need to format the input frames : scaling to the model input dimension, adding a batch dimension, dividing the pixel values by 255 to have a range 0-1.

    


    FFmpeg has a filter that can use tensorflow models thanks to dnn_processing, but I'm wondering about these preprocessing steps. I tried to read the dnn_backend_tf.c file in ffmpeg's github repo, but C is not my forte. I'm guessing it adds a batch dimension somewhere otherwise the model wouldn't run, but I'm not sure about the rest.

    


    Here is my current command :

    


    ffmpeg \
    -i $FILE -filter_complex \
    "[0:v]scale=160:96,format=rgb24,dnn_processing=dnn_backend=tensorflow:model=$MODEL:input=input_1:output=segment[masks];[masks]extractplanes=2[mask]" \
    -map "[mask]" output.png


    


      

    • I'm already applying a scaling to match the input dimension.

      • 


    • I wrote this [masks]extractplanes=2[mask] because the model outputs a HxWx2 tensor (background mask and foreground mask) and I want to keep the foreground mask.

      • 


    


    The result I get with this command is the following (input-output) :

    


    Output example

    


    I'm not sure how to interpret the problems in this output. In python I can easily get a nice grayscale output :

    


    enter image description here

    


    I'm trying to obtain something similar with FFmpeg.

    


    Any suggestion or insights to obtain a correct output with FFmpeg would be greatly appreciated.

    


    PS : If I try to apply this on a video file, it hits a Segmentation Fault somewhere before getting any output so I stick with testing on an image for now.

    


  • FFMPEG multiple crop on same video

    18 juin 2017, par djdan_23

    I have one .mkv that have 4 sections in time that need to be cropped.
    (Meaning that the top-bot blacks bars appears sometimes during the viewing).
    How can I do that using FFMPEG.
    I know about crop for an entire film, but using it at 4 different places on the same video, that I don’t.
    Thanks at advance.

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