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• Anomalie #3273 (Nouveau) : Bug fonctions avancées sous spip 3.0.17

  25 septembre 2014, par Vincent Marty

  Sous spip 3.0.17 (Révision 21515) il est impossible d’accéder à l’url http://www.monsite.fr/ecrire/?exec=configurer_avancees
  Le navigateur (Chrome) retourne une erreur : "Echec du chargement de la page - aucune donée reçue"

  Ce bug n’est pas présent sur spip 3.0.11 ou 3.0.18-dev

• ffmpeg convert mov file to mp4 for HTML5 video tag IE9

  27 septembre 2016, par Adidi

  I looked everywhere here and on google - there is no valid command that works for IE9.
  some how IE9 is missing something.
  All that I tried worked everywhere else : chrome,safari,mobile device etc...
  I want one command that will convert it and I can use it in every device suppose to support mp4 in HTML5 video tag.

  I use this commands :

  ffmpeg -i movie.mov -vcodec copy -acodec copy out.mp4
  
  ffmpeg -i movie.mov -vcodec libx264 -vprofile high -preset slow -b:v 500k -maxrate 500k -bufsize 1000k -vf scale=-1:480 -threads 0 -acodec libvo_aacenc -b:a 128k -pix_fmt yuv420p outa.mp4
  
  ffmpeg -i movie.mov -b:V 1500k -vcodec libx264 -preset fast -g 30 adel.mp4
  
  ffmpeg -i movie.mov -acodec aac -strict experimental -ac 2 -ab 160k -vcodec libx264 -preset slow -f mp4 -crf 22 lamlam.mp4
  
  ffmpeg -i movie.mov -acodec aac -strict experimental -ac 2 -ab 160k -vcodec libx264 -preset slow -profile:v baseline -level 30 -maxrate 10000000 -bufsize 10000000 -f mp4 -threads 0 adiel.mp4

  etc.. again all this commands produce a valid mp4 file which works on chrome,safari etc... and works even when I launch them in windows itself using window media player.
  When I put this file in the video tag (I am using http://videojs.com/) in IE9 it isn’t working !

  <div class="vidoco-content" style="margin-top: 20px;">
  
  <video class="video-js vjs-default-skin vidoco-center" controls="controls" preload="none" width="600" height="400" poster="&lt;?php echo(DOMAIN); ?>static/test.jpg">
  
      <source src="&lt;?php echo(DOMAIN); ?>static/out.mp4" type="video/mp4"></source>
  
  </video>
  
  </div>

  If I use the software miro video converter to convert the same mov file to mp4 - it converted fine and I can play it in IE9 !
  miro converter is also using embedd ffmpeg inside it so I am sure it’s only a metter of the right ffmpeg command and parameters.
  In my apache htaccess I set the correct mime types for my files and I see it indeed correct when looking in IE developer tools :

  AddType audio/aac .aac
  
  AddType audio/mp4 .mp4 .m4a
  
  AddType audio/mpeg .mp1 .mp2 .mp3 .mpg .mpeg
  
  AddType audio/ogg .oga .ogg
  
  AddType audio/wav .wav
  
  AddType audio/webm .webm
  
  
  
  AddType video/mp4 .mp4 .m4v
  
  AddType video/ogg .ogv
  
  AddType video/webm .webm

  I am struggling with this for a long time so any help would be much appreciated.

  Thanks !

• Summary Video Accessibility Talk

  23 avril 2013, par silvia

  I’ve just got off a call to the UK Digital TV Group, for which I gave a talk on HTML5 video accessibility (slides best viewed in Google Chrome).

  The slide provide a high-level summary of the accessibility features that we’ve developed in the W3C for HTML5, including :

  • Subtitles & Captions with WebVTT and the track element
  • Video Descriptions with WebVTT, the track element and speech synthesis
  • Chapters with WebVTT for semantic navigation
  • Audio Descriptions through synchronising an audio track with a video
  • Sign Language video synchronized with a main video

  I received some excellent questions.

  The obvious one was about why WebVTT and not TTML. While for anyone who has tried to implement TTML support, the advantages of WebVTT should be clear, for some the decision of the browsers to go with WebVTT still seems to be bothersome. The advantages of CSS over XSL-FO in a browser-context are obvious, but not as much outside browsers. So, the simplicity of WebVTT and the clear integration with HTML have to speak for themselves. Conversion between TTML and WebVTT was a feature that was being asked for.

  I received a question about how to support ducking (reduce the volume of the main audio track) when using video descriptions. My reply was to either use video descriptions with WebVTT and do ducking during the times that a cue is active, or when using audio descriptions (i.e. actual audio tracks) to add an additional WebVTT file of kind=metadata to mark the intervals in which to do ducking. In both cases some JavaScript will be necessary.

  I received another question about how to do clean audio, which I had almost forgotten was a requirement from our earlier media accessibility document. “Clean audio” consists of isolating the audio channel containing the spoken dialog and important non-speech information that can then be amplified or otherwise modified, while other channels containing music or ambient sounds are attenuated. I suggested using the mediagroup attribute to provide a main video element (without an audio track) and then the other channels as parallel audio tracks that can be turned on and off and attenuated individually. There is some JavaScript coding involved on top of the APIs that we have defined in HTML, but it can be implemented in browsers that support the mediagroup attribute.

  Another question was about the possibilities to extend the list of @kind attribute values. I explained that right now we have a proposal for a new text track kind=”forced” so as to provide forced subtitles for sections of video with foreign language. These would be on when no other subtitle or caption tracks are activated. I also explained that if there is a need for application-specific text tracks, the kind=”metadata” would be the correct choice.

  I received some further questions, in particular about how to apply styling to captions (e.g. color changes to text) and about how closely the browser are able to keep synchronization across multiple media elements. The earlier was easily answered with the ::cue pseudo-element, but the latter is a quality of implementation feature, so I had to defer to individual browsers.

  Overall it was a good exercise to summarize the current state of HTML5 video accessibility and I was excited to show off support in Chrome for all the features that we designed into the standard.