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• Set background colour when converting flv to mp4 with ffmpeg

  28 août 2012, par Castles

  I'm attempting to convert flv files (with an alpha channel) that are uploaded to a server to html5 compatible formats. I've got the conversion working but the transparency is rendered as black. What I would like to do is have the ability to specify a colour.

  Is it possible to convert the video and specify the colour ?

  Alternatively, am I able to overlay the video with transparency on a still image that I generate ?

  Update
  I may of solved my own question... Here is my ffmpeg command :

  `ffmpeg -loop_input -f image2 -i background.png -r 25 -t 10 -an -level 21 -refs 2 -b 345k -bt 345k -acodec libfaac -vcodec libx264 -ac 2 -ab 96k -ar 44100 -vf "movie=input.flv, scale=370:500 [logo]; [in][logo] overlay=0:0 [out]" -y -threads 0 output.mp4`

  Which works.. I just need to generate a background image at the right dimensions on the server before converting.

• Want to convert my 16:9 size MKV video to 4:3 size AVI video file

  19 septembre 2012, par Bimal Rekhadiya

  I have a video in MKV format and it's size is 720x304 (16:9 ratio) size video.

  I want to convert it to AVi format (using xvid video codec). The output file size should be 480x360 (4:3 ratio) and also want to keep the original (16:9) ratio so it should be cinemascope (black areas at top and bottom).

  I am on Ubuntu linux OS so I can use mencoder, avconv(ffmpeg) or any tool that work on Linux.

  I am trying this command :

  avconv -i sample.mkv -vcodec libxvid -r 25 -b 1200 -aspect 4:3 -q 1 t.avi

  But the problem is that the video is stretched to 4:3 and I want to keep original video's ratio and want to add black boxes at top and bottom so it will look cinemascope.

  Please provide me command to do this.

• What encoding settings for BlackBerry HTML5 streaming ?

  27 septembre 2012, par user1441859

  For several days I've been desperately trying to get my videos stream on BlackBerry as well as the major desktop and mobile browser.
  The videos are embedded in this way :

  <video preload="auto" controls="controls">
  
  <source src="url.mp4" type="video/mp4"></source>
  
  <source src="url.ogv" type="video/ogv"></source>
  
  //flash fallback
  
  </video>

  When opening the page in the BB browser the black video frame with the controls appears but when I try to play the video the frame stays black and displays an error message : "Video portion is of an unsupported format".
  Sound does play however.

  By now I have tried H.264 and mpeg4 with AAC audio and both of them don't play properly on my BB (OS version 6.0).
  I've been using ffmpeg to encode the files.