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  • D’autres logiciels intéressants

    12 avril 2011, par

    On ne revendique pas d’être les seuls à faire ce que l’on fait ... et on ne revendique surtout pas d’être les meilleurs non plus ... Ce que l’on fait, on essaie juste de le faire bien, et de mieux en mieux...
    La liste suivante correspond à des logiciels qui tendent peu ou prou à faire comme MediaSPIP ou que MediaSPIP tente peu ou prou à faire pareil, peu importe ...
    On ne les connais pas, on ne les a pas essayé, mais vous pouvez peut être y jeter un coup d’oeil.
    Videopress
    Site Internet : (...)

  • 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 (...)

  • Emballe médias : à quoi cela sert ?

    4 février 2011, par

    Ce plugin vise à gérer des sites de mise en ligne de documents de tous types.
    Il crée des "médias", à savoir : un "média" est un article au sens SPIP créé automatiquement lors du téléversement d’un document qu’il soit audio, vidéo, image ou textuel ; un seul document ne peut être lié à un article dit "média" ;

Sur d’autres sites (4045)

  • Exporting MPEG Transport Stream (.ts) keyframes to images in C/C++ ? Libavcodec / FFMPEG ?

    11 mai 2021, par CyberBully2003

    I have some buffers made up of 188 byte TS packets. When I write them to a file, I can successfully view these .ts files in a video player. MPEG-2/H.264 is the format of the Transport Streams.

    


    Now, I would like to export the keyframes from these Transport Streams buffers (or .ts files) as .jpeg or some other common image format in my C/C++ project.

    


    This is a trivial task from the command line using ffmpeg, where I just feed it the .ts file and some parameters.

    


    However, for the purpose of this project, I would like to accomplish this conversion/exporting of keyframes as images code-side in my current C/C++ directory because the raw bytes from these generated images will be put into another format.

    


    People online seem to recommend using libavcodec. There is an mpegets file in the ffmpeg source that seems like it might have some of the backend to do what I want.

    


    However, the steps needed to achieve this task using the library is not apparent.

    


    I know I could call ffmpeg from C++ and use stdin, but this isn't a preferred solution for this project.

    


    If someone could give me some guidance (and even better some example code) to accomplish this task, it would be greatly appreciated !

    


  • FFMPEG -f segment and FFPROBE keyframes are different

    18 juillet 2019, par user2190197

    I have a online video editor. And i want fast strip and concat mp4 files. For this i use code like this :

    For get keyframes :

    exe_ffprobe("-select_streams v -skip_frame nokey -show_frames -show_entries frame=pkt_pts_time,pict_type $input_file");

    Sample Result :

    array (
    
  0 => '0.083417',
    
  1 => '2.085419',
    
  2 => '4.170838',
    
...
    
  12 => '24.149149',
    
  13 => '26.234568',
    
  14 => '27.569236',       < Why ffmpeg missed this keyframe?
    
  15 => '29.654655',
    
...
    
  230 => '466.966967',
    
  231 => '469.052386',
    
  232 => '471.137804',
    
  233 => '473.223223',
    
  234 => '475.308642',
    
  235 => '477.394061',
    
  236 => '479.479479',
    
)
    
...

    For split video :

    exe_ffmpeg("-y -i $input_file -c copy -map 0 -segment_list segments.csv -f segment -reset_timestamps 1 path/to/%d.mp4");

    Sample result :

    0.mp4,0.000000
    
1.mp4,2.085419
    
2.mp4,4.170838
    
...
    
12.mp4,24.149149
    
13.mp4,26.234568
    
14.mp4,29.654655
    
15.mp4,31.740073
    
...
    
230.mp4,475.308642
    
231.mp4,477.394061
    
232.mp4,479.479479
    
end

    But count of keyframes from ffprobe, and count splitted videos are different.

    So how i can segment or get keyframes correctly, to match the count

    Also, keyframes and segments.csv are differently too, but more of keyframes has correct timestamps

  • ffmpeg how to extract X frames every Y interval from url efficiently

    13 décembre 2018, par Luay Gharzeddine

    I’m trying to gather data for a datascience project, and am downloading frames from online videos using ffmpeg. I want to download a subset of the frames in the video, without needing to be precise about which, the only requirement is that they are reasonably spaced apart from each other.

    I have tried

    ffmpeg -i "http://www.somevideo.com" -r 1 -f image2 "image%06d.jpg"

    and

    ffmpeg -i "http://www.somevideo.com" -vf fps=1 "image%06d.jpg"

    and eventually found the following method

    ffmpeg -ss offset1 -i "http://www.somevideo.com" -ss offset2 -i "http://www.somevideo.com" -map 0:v -frames:v 10 -start_number 0 "image%06d.jpg" -map 1:v -frames:v 10 -start_number 10 "image%06d.jpg"

    and all work, but are slow. I have found a hack where I run the following command multiple times, at different offsets, and it seems to be the fastest (where each ffmpeg command is run in parallel multithreaded)

    ffmpeg -ss offset -i "http://www.somevideo.com" -vframes frames_per_fragment -an -start_number start_index "image%06d.jpg"

    this about 25% faster than the previous method

    Is there a faster way to do this ? The issue is that downloading over a network is a bottleneck, so I want to download only the frames I need. I’m looking to download videos/frames in bulk, so any speed improvement would be helpful.

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