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• Combine multiple videos into one

  10 janvier 2012, par StackedCrooked

  I have three videos :

  • a lecture that was filmed with a video camera
  • a video of the desktop capture of the computer used in the lecture
  • and the video of the whiteboard

  I want to create a final video with those three components taking up a certain region of the screen.

  Is open-source software that would allow me to do this (mencoder, ffmpeg, virtualdub..) ? Which do you recommend ?

  Or is there a C/C++ API that would enable me to create something like that programmatically ?

  Edit
  There will be multiple recorded lectures in the future. This means that I need a generic/automated solution.

  I'm currently checking out if I could write an application with GStreamer to do this job. Any comments on that ?

  Solved !
  I succeeded in doing this with GStreamer's videomixer element. I use the gst-launch syntax to create a pipeline and then load it with gst_parse_launch. It's a really productive way to implement complex pipelines.

  Here's a pipeline that takes two incoming video streams and a logo image, blends them into one stream and the duplicates it so that it simultaneously displayed and saved to disk.

    desktop. ! queue
  
             ! ffmpegcolorspace
  
             ! videoscale
  
             ! video/x-raw-yuv,width=640,height=480
  
             ! videobox right=-320
  
             ! ffmpegcolorspace
  
             ! vmix.sink_0
  
    webcam. ! queue
  
            ! ffmpegcolorspace
  
            ! videoscale
  
            ! video/x-raw-yuv,width=320,height=240
  
            ! vmix.sink_1
  
    logo. ! queue
  
          ! jpegdec
  
          ! ffmpegcolorspace
  
          ! videoscale
  
          ! video/x-raw-yuv,width=320,height=240
  
          ! vmix.sink_2
  
    vmix. ! t.
  
    t. ! queue
  
       ! ffmpegcolorspace
  
       ! ffenc_mpeg2video
  
       ! filesink location="recording.mpg"
  
    t. ! queue
  
       ! ffmpegcolorspace
  
       ! dshowvideosink
  
    videotestsrc name="desktop"
  
    videotestsrc name="webcam"
  
    multifilesrc name="logo" location="logo.jpg"
  
    videomixer name=vmix
  
               sink_0::xpos=0 sink_0::ypos=0 sink_0::zorder=0
  
               sink_1::xpos=640 sink_1::ypos=0 sink_1::zorder=1
  
               sink_2::xpos=640 sink_2::ypos=240 sink_2::zorder=2
  
    tee name="t"

• Simulate concatenated file using hard link ?

  16 décembre 2011, par Sugrue

  I have multiple parts of a single file which I want a 3rd party c++/c# plugin to read as a single file. Basically, when the plugin file reader gets to the end of one file-part, I want it to continue to the next one.

  (For anyone interested, the plugin is Aforge.Net FFMpeg, and I am trying to import VOB files)

  It looks like quite a task to reprogram the plugin. An alternative solution is to copy the file parts to a concatenated file, but this is slow because I am dealing with many GBs of data.

  Is it possible to use a file system hard link to point to multiple files ? Or is there some other way to 'fake' a concatenated file ? Using command line FFMpeg I can use 'type' to live stream a concatenate file in, but I can't figure out how to achieve this in c# with this plugin.

  I am on Windows 7.

• How to implement HTTP Live Streaming server on Unix ?

  5 septembre 2012, par alex

  I just realized that Apple required HTTP Live Streaming in order to view videos in iPhone apps. I was not aware of this before... I am now trying to understand what this involves so I can decide whether I want to do the work and make the videos available in 3G or limit video playing to users who are connected to wi-fi.

  I read the overview provided by Apple, and now understand that my server needs to segment and index my media files. I also understand that I don't have to host the content to be able to stream it (I can point to a video hosted somewhere else, right ?).

  What's not clear to me at this point is what to implement on my server (Ubuntu Hardy) to do the actual segmenting and indexing on the fly (once again, I do not host the videos I want to serve).

  I found a link explaining how to install FFmpeg and X264, but I don't know if this is the best solution (since I have an Ubuntu server, I can't use the Apple Live Streaming tools, is it correct ?). Also, I do not understand at which point my server knows that a video needs to be converted and starts the job...

  Any feedback that could help me understand exactly what to do on the server side to be able to stream videos on my iPhone app in 3G would be greatly appreciated ! (Oh, and just it makes any difference, my app back-end is in Rails)