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  • Keeping control of your media in your hands

    13 avril 2011, par

    The vocabulary used on this site and around MediaSPIP in general, aims to avoid reference to Web 2.0 and the companies that profit from media-sharing.
    While using MediaSPIP, you are invited to avoid using words like "Brand", "Cloud" and "Market".
    MediaSPIP is designed to facilitate the sharing of creative media online, while allowing authors to retain complete control of their work.
    MediaSPIP aims to be accessible to as many people as possible and development is based on expanding the (...)

  • 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 (...)

  • Submit bugs and patches

    13 avril 2011

    Unfortunately a software is never perfect.
    If you think you have found a bug, report it using our ticket system. Please to help us to fix it by providing the following information : the browser you are using, including the exact version as precise an explanation as possible of the problem if possible, the steps taken resulting in the problem a link to the site / page in question
    If you think you have solved the bug, fill in a ticket and attach to it a corrective patch.
    You may also (...)

Sur d’autres sites (10684)

  • Why is one ffmpeg webm dash stream much larger than the others ?

    5 janvier 2017, par ranvel

    Over the summer, I worked on putting together a script which took a x264 video/mp3 stream and broke it up into the different streams so that it would work via MSE-DASH. (Based heavily on the instructions on the webmproject.org website) Those same scripts have ceased to work, turning a 6GB video into several 25 Gb videos. I kept up with updates of ffmpeg and so I don’t know when it stopped working, but I am guessing it was due to the way that their DASH Webm implementation was updated.

    I found new method which works better, but still has a major problem with one stream. I was hoping someone could explain how this encoding works so that I could understand the underlying cause.

    #!/bin/bash
    
COMMON_OPTS="-map 0:0 -an -threads 11 -cpu-used 4 -cmp chroma"
    
WEBM_OPTS="-f webm -c:v vp9 -keyint_min 50 -g 50 -dash 1"
    

    
ffmpeg -i $1 -vn -acodec libvorbis -ab 128k audio.webm &
    
ffmpeg -i $1 $COMMON_OPTS $WEBM_OPTS -b:v 500k -vf scale=1280:720 -y vid-500k.webm &
    
ffmpeg -i $1 $COMMON_OPTS $WEBM_OPTS -b:v 700k -vf scale=1280:720 -y vid-700k.webm & 
    
ffmpeg -i $1 $COMMON_OPTS $WEBM_OPTS -b:v 1000k -vf scale=1280:720 -y vid-1000k.webm &
    
ffmpeg -i $1 $COMMON_OPTS $WEBM_OPTS -b:v 1500k -vf scale=1280:720 -y vid-1500k.webm  

    The transcode is not yet complete, but you can see where this is headed :

    -rw-r--r--  1 user  staff    87M Jan  4 23:27 audio.webm
    
-rw-r--r--  1 user  staff    27M Jan  4 23:42 vid-1000k.webm
    
-rw-r--r--  1 user  staff   285M Jan  4 23:42 vid-1500k.webm
    
-rw-r--r--  1 user  staff    15M Jan  4 23:42 vid-500k.webm
    
-rw-r--r--  1 user  staff    20M Jan  4 23:42 vid-700k.webm

    The 1500k variant is disproportionately larger than the other streams.

    The other problem is that when I use a shorter video, lets say eight or nine minutes, the above configuration runs as expected and everything is perfect. I don’t know where the limit for this is since each test costs a lot of processing power and time, but if it’s less than ten minutes, it works and if its longer than an hour, it produces massive files.

  • lavf/dashenc : Write media trailers when DASH trailer is written.

    3 décembre 2018, par Andrey Semashev
    lavf/dashenc : Write media trailers when DASH trailer is written.

    This commit ensures that all (potentially, long) filesystem activity is
    
performed when the user calls av_write_trailer on the DASH libavformat
    
context, not when freeing the context. Also, this defers media segment
    
deletion until after the media trailers are written.
    • [DH] libavformat/dashenc.c

  • lavf/dashenc : Write media trailers when DASH trailer is written.

    29 novembre 2018, par Andrey Semashev
    lavf/dashenc : Write media trailers when DASH trailer is written.

    This commit ensures that all (potentially, long) filesystem activity is
    
performed when the user calls av_write_trailer on the DASH libavformat
    
context, not when freeing the context. Also, this defers media segment
    
deletion until after the media trailers are written.
    • [DH] libavformat/dashenc.c

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