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  • Les formats acceptés

    28 janvier 2010, par

    Les commandes suivantes permettent d’avoir des informations sur les formats et codecs gérés par l’installation local de ffmpeg :
    ffmpeg -codecs ffmpeg -formats
    Les format videos acceptés en entrée
    Cette liste est non exhaustive, elle met en exergue les principaux formats utilisés : h264 : H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 m4v : raw MPEG-4 video format flv : Flash Video (FLV) / Sorenson Spark / Sorenson H.263 Theora wmv :
    Les formats vidéos de sortie possibles
    Dans un premier temps on (...)

  • 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 (...)

  • Ajouter notes et légendes aux images

    7 février 2011, par

    Pour pouvoir ajouter notes et légendes aux images, la première étape est d’installer le plugin "Légendes".
    Une fois le plugin activé, vous pouvez le configurer dans l’espace de configuration afin de modifier les droits de création / modification et de suppression des notes. Par défaut seuls les administrateurs du site peuvent ajouter des notes aux images.
    Modification lors de l’ajout d’un média
    Lors de l’ajout d’un média de type "image" un nouveau bouton apparait au dessus de la prévisualisation (...)

Sur d’autres sites (6473)

  • the problem using "yt-dlp —download-sections" [closed]

    15 avril 2024, par talent

    I tried to use "yt-dlp —download-sections" to download specific segment of YouTube video.

    


    But I have confronted some error.

    


    If I use the cammand as followed, it will be ok, and download the whole video successfully.

    


    yt-dlp -P [path] [URL]


    


    But, if I add the "—download-sections" to download specific segment, it seems something wrong.
the command is as followed.

    


    yt-dlp -P [path] --download-sections "*00:08:06-00:08:17" https://www.youtube.com/watch?v=6Vkmb4cUuLs 


    


    the eccor message

    


    Plus, the operation system is Windows. And I have used vpn(proxy).

    


    ffmpeg configuration

    


    I'd be tremendously appreciated if anyone can give me the early response to solve it !!!

    


  • YouTube's HD Video Streaming Server Technology ?

    30 septembre 2013, par bgentry

    Lately I've been researching different methods for streaming MP4s to the browser. Flash Media Server is an obvious choice here (using Cloudfront), and most solutions I've seen use the RTMP protocol.

    However, I spent some time on YouTube with Firebug and Chrome debugger figuring out how their streaming worked and I discovered some interesting differences between some of their videos and quality rates.

    My two sample videos are A and B. A is available up to 480p and B is available up to 1080p. For both videos, all rates up to 480p are served in an FLV container with H.264 video and AAC audio, over HTTP. What's interesting here is that if you have not yet downloaded (cached) the entire video, and you try to skip forward to an uncached part of the video, a new request will be made with a 'begin' parameter equal to the target offset in milliseconds. Example from Video A at 480p :

    http://v11.lscache8.c.youtube.com/videoplayback?ip=0.0.0.0&sparams=id%2Cexpire%2Cip%2Cipbits%2Citag%2Calgorithm%2Cburst%2Cfactor%2Coc%3AU0dWTldQVF9FSkNNNl9PSlhJ&fexp=904806%2C902906%2C903711&algorithm=throttle-factor&itag=35&ipbits=0&burst=40&sver=3&expire=1279756800&key=yt1&signature=D2D704D63C242CF187CAA5B5D5BAFB8DFACAC5FF.39180C01559C976717B651A7EB1D0C6249231EB7&factor=1.25&id=8568eb3135971f6f&begin=111863

    Response Headers:
    Cache-Control:public,max-age=23472
    Connection:close
    Content-Length:14320637
    Content-Type:video/x-flv
    Date:Wed, 21 Jul 2010 17:23:48 GMT
    Expires:Wed, 21 Jul 2010 23:55:00 GMT
    Last-Modified:Wed, 19 May 2010 12:31:41 GMT
    Server:gvs 1.0
    X-Content-Type-Options:nosniff

    The file returned by this URL is a fully valid FLV containing only the portion of the video after the requested offset.

    I did the same kind of test on the higher resolution versions of Video B. At 720p and 1080p, YouTube will return a video in an MP4 container, also with H.264 video and AAC audio. What's impressive to me is that their server takes the same type of offset for an MP4 video (via the 'begin' parameter) and returns a valid, streamable MP4 (moov atom at the front of the file with correct offsets) that also only includes the requested portion of the video.

    So, how does YouTube do this ? How do they generate the FLV or MP4 container on the fly with the correct headers and only the desired segment of the requested video ? I know this can be accomplished using FFMPEG to seek to the desired start point and the qt-faststart script to reposition the moov atom to the front of the stream, but it seems like this would be too slow to handle on-demand for millions of YouTube viewers.

    Ideas ?

    Thanks in advance !

    Footnote : I am not allowed to include more than 1 link at this point, so here is Video A's URL : http:// www.youtube .com/watch ?v=hWjrMTWXH28 "Video available up to 480p"

  • Download from YouTube as ".wav" instead of ".webm"

    11 août 2022, par Bastian Gerjol

    I am trying to extract an audio from a YouTube Video as an .wav file.
However, the script that I am running keeps giving me .webm files.
The code I am using is the following :

    


    from __future__ import unicode_literals
import youtube_dl

ydl_opts = {
    'format': 'bestaudio/best',
    'postprocessors': [{
        'key': 'FFmpegExtractAudio',
        'preferredcodec': 'wav',
        'preferredquality': '192'
    }],
    'postprocessor_args': [
        '-ar', '16000'
    ],
    'prefer_ffmpeg': True,
    'keepvideo': True
}

with youtube_dl.YoutubeDL(ydl_opts) as ydl:
    ydl.download(['https://www.youtube.com/watch?v=2Xq7iJKzhR4'])


    


    Is there a way to change the output and keep the highest possible audio quality ?

    


    I tried setting prefer_ffmpeg': True to False & keepvideo': True to False but that did not change anything.

    


    I would appreciate suggestions and please keep in mind that I never used Python before.