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Autres articles (35)

  • Contribute to a better visual interface

    13 avril 2011

    MediaSPIP is based on a system of themes and templates. Templates define the placement of information on the page, and can be adapted to a wide range of uses. Themes define the overall graphic appearance of the site.
    Anyone can submit a new graphic theme or template and make it available to the MediaSPIP community.

  • Supporting all media types

    13 avril 2011, par

    Unlike most software and media-sharing platforms, MediaSPIP aims to manage as many different media types as possible. The following are just a few examples from an ever-expanding list of supported formats : images : png, gif, jpg, bmp and more audio : MP3, Ogg, Wav and more video : AVI, MP4, OGV, mpg, mov, wmv and more text, code and other data : OpenOffice, Microsoft Office (Word, PowerPoint, Excel), web (html, CSS), LaTeX, Google Earth and (...)

  • Soumettre bugs et patchs

    10 avril 2011

    Un logiciel n’est malheureusement jamais parfait...
    Si vous pensez avoir mis la main sur un bug, reportez le dans notre système de tickets en prenant bien soin de nous remonter certaines informations pertinentes : le type de navigateur et sa version exacte avec lequel vous avez l’anomalie ; une explication la plus précise possible du problème rencontré ; si possibles les étapes pour reproduire le problème ; un lien vers le site / la page en question ;
    Si vous pensez avoir résolu vous même le bug (...)

Sur d’autres sites (5472)

  • x264 : How to Correctly Use quant_offsets ?

    25 août 2022, par Eynnzerr

    Suppose I need to encode different regions with different QPs in one frame, i.e. RoI(regions of interest) encoding. I searched all over the internet and was only told that quant_offsets can meet my demand. However, none of them told me exactly how to use it, and I can't find any official documentation about it. I read the source code of x264 and did experiments, and find it only adds an offset to the qp decision x264 has made, rather than exactly set the qp value I want.

    


    Is there a possible way that I can have x264 encode these regions using the qp value I've explictly given instead of adding offsets based on what it decided on its own ? Many thanks !

    


  • x264 : How to Correctly Use quant_offsets ?

    25 août 2022, par Eynnzerr

    Suppose I need to encode different regions with different QPs in one frame, i.e. RoI(regions of interest) encoding. I searched all over the internet and was only told that quant_offsets can meet my demand. However, none of them told me exactly how to use it, and I can't find any official documentation about it. I read the source code of x264 and did experiments, and find it only adds an offset to the qp decision x264 has made, rather than exactly set the qp value I want.

    


    Is there a possible way that I can have x264 encode these regions using the qp value I've explictly given instead of adding offsets based on what it decided on its own ? Many thanks !

    


  • FFMPEG conversion creates a smaller files despite unchanged codecs

    26 octobre 2015, par Idan

    I have a h264/aac video mp4 file that FFMPEG says this about :

      Metadata:
    
    major_brand     : qt
    
    minor_version   : 0
    
    compatible_brands: qt
    
    creation_time   : 2015-10-15 16:41:52
    
  Duration: 00:03:36.20, start: 0.000000, bitrate: 4298 kb/s
    
    Stream #0:0(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 127 kb/s (default)
    
    Metadata:
    
      creation_time   : 2015-10-15 16:41:53
    
      handler_name    : Core Media Data Handler
    
    Stream #0:1(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1280x720, 4160 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc (default)
    
    Metadata:
    
      creation_time   : 2015-10-15 16:41:53
    
      handler_name    : Core Media Data Handler
    
      encoder         : H.264

    Then, I run a conversion on it while keeping it the same codecs and resolution with this command line :

    ffmpeg -i x.mp4 -vcodec h264 -acodec libvo_aacenc y.mp4

    The resulting output file info is :

      Metadata:
    
    major_brand     : isom
    
    minor_version   : 512
    
    compatible_brands: isomiso2avc1mp41
    
    encoder         : Lavf56.36.100
    
  Duration: 00:03:36.29, start: 0.033333, bitrate: 1913 kb/s
    
    Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 1780 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    
    Metadata:
    
      handler_name    : VideoHandler
    
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    
    Metadata:
    
      handler_name    : SoundHandler

    It seems that the input and output file should be identical but the input file is 116MB and the resulting output file is 51.7MB.

    If the codecs and resolution are the same and there is not change in the video quality for the naked eye, why is the file size is so different ?

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