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• Converting mp4 audio to webm with ffmpeg - unable to find suitable output for webm

  13 janvier 2015, par JDStraughan

  I have a custom heroku buildpack that is installing ffmpeg, libvorbis, etc.

  When I run ffmpeg I get the following output :

  FFmpeg version SVN-r0.5.9-4:0.5.9-0ubuntu0.10.04.3, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  
  
  
  configuration: --extra-version=4:0.5.9-0ubuntu0.10.04.3 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --disable-stripping --disable-vhook --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --enable-shared --disable-static
  
    libavutil     49.15. 0 / 49.15. 0
  
    libavcodec    52.20. 1 / 52.20. 1
  
    libavformat   52.31. 0 / 52.31. 0
  
    libavdevice   52. 1. 0 / 52. 1. 0
  
    libavfilter    0. 4. 0 /  0. 4. 0
  
    libswscale     0. 7. 1 /  0. 7. 1
  
    libpostproc   51. 2. 0 / 51. 2. 0
  
    built on Jan 24 2013 19:42:59, gcc: 4.4.3
  
  At least one output file must be specified

  I’m trying to convert mp4 audio to webm audio.

  Here is the command I am using :

  ~/public/audio $ ffmpeg -i sample.mp3 sample.webm

  And the output :

  FFmpeg version SVN-r0.5.9-4:0.5.9-0ubuntu0.10.04.3, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  
    configuration: --extra-version=4:0.5.9-0ubuntu0.10.04.3 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --disable-stripping --disable-vhook --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --enable-shared --disable-static
  
    libavutil     49.15. 0 / 49.15. 0
  
    libavcodec    52.20. 1 / 52.20. 1
  
    libavformat   52.31. 0 / 52.31. 0
  
    libavdevice   52. 1. 0 / 52. 1. 0
  
    libavfilter    0. 4. 0 /  0. 4. 0
  
    libswscale     0. 7. 1 /  0. 7. 1
  
    libpostproc   51. 2. 0 / 51. 2. 0
  
    built on Jan 24 2013 19:42:59, gcc: 4.4.3
  
  Input #0, mp3, from 'sample.mp3':
  
    Duration: 00:00:01.56, start: 0.000000, bitrate: 76 kb/s
  
      Stream #0.0: Audio: mp3, 24000 Hz, stereo, s16, 64 kb/s
  
  Unable to find a suitable output format for 'sample.webm'

  This works fine on my OSX install, but on Ubuntu 14.04 I’m getting these errors.

  What do I need to do so .webm files can be the destination ?

• cross-platform syntax for mp4 embedded in html5

  11 janvier 2015, par CodeMed

  The code below produces a properly embedded video in firefox, but does not display properly in internet explorer or in android. I have all my browsers set to automatically update, so they are all always running the most current versions.

  In `internet explorer`, the code below leaves a large blank space where the  
  
  video should be.  The user has to hover over the large blank space before the  
  
  controls become visible.  
  
  
  
  In `android`, the code below produces an unusable/unclickable area, and the  
  
  user has to greatly zoom the focus to get the small start button to become  
  
  big enough to click to start the video.  
  
  
  
  However, in `firefox`, the code below shows the first frame of the video,  
  
  which you can click to start the video.  

  How can I change the code below to get all three of these browsers to show the first frame when the page loads, and for the video to be start-able when the user clicks on the first frame ?

  Here is a link to the video file on a file sharing site.

  Here is the ffmeg code for processing the video :

  ffmpeg -y -i SourceFile.mp4 -s 1280x720 -c:v libx264 -b 3M -strict -2 -movflags faststart DestFile.mp4

  Thanks to offbeatmammal for getting me this far.
  Here is the html5 code for embedding the video in a web page browser :

  <video width="640" height="480" controls="controls">
  
      <source src="somefile.mp4" type="video/mp4">
  
      Your browser does not support the video tag.
  
  </source></video>

• New Challenges

  1er janvier 2014, par silvia

  I finished up at Google last week and am now working at NICTA, an Australian ICT research institute.

  My work with Google was exciting and I learned a lot. I like to think that Google also got a lot out of me – I coded and contributed to some YouTube caption features, I worked on Chrome captions and video controls, and above all I worked on video accessibility for HTML at the W3C.

  I was one of the key authors of the W3C Media Accessibility Requirements document that we created in the Media Accessibility Task Force of the W3C HTML WG. I then went on to help make video accessibility a reality. We created WebVTT and the <track> element and applied it to captions, subtitles, chapters (navigation), video descriptions, and metadata. To satisfy the need for synchronisation of video with other media resources such as sign language video or audio descriptions, we got the MediaController object and the @mediagroup attribute.

  I must say it was a most rewarding time. I learned a lot about being productive at Google, collaborate successfully over the distance, about how the WebKit community works, and about the new way of writing W3C standard (which is more like pseudo-code). As one consequence, I am now a co-editor of the W3C HTML spec and it seems I am also about to become the editor of the WebVTT spec.

  At NICTA my new focus of work is WebRTC. There is both a bit of research and a whole bunch of application development involved. I may even get to do some WebKit development, if we identify any issues with the current implementation. I started a week ago and am already amazed by the amount of work going on in the WebRTC space and the amazing number of open source projects playing around with it. Video conferencing is a new challenge and I look forward to it.