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• Stream frame from video to pipeline and publish it to HTTP mjpeg via ffmpeg

  18 juillet 2018, par Rafał Sardaw

  Let’s say I have very simple program which has been written in C++ with usage of OpenCV 3.4 under Windows 10.

  VideoCapture cap("test.avi");
  
  Mat frame; 
  
  while(true){
  
      if (!cap.read(frame))  
  
      { 
  
          break;
  
      }
  
      // SEND FRAME TO PIPE
  
  }

  It’s just simple example of reading frame by frame avi video, but in the end it’s going to be server-side application which produces modified stream from few ip cameras. I want to use html5 video tag to display output directly on website, but it’s quite hard to find useful information related with that topic ( for Windows ). If I understand it correctly I need to define pipeline and send there MJPEG stream, with help of FFMPEG, where FFMPEG will create local HTTP server on specific port. Anyone ever challenged similar task under Windows ? I guess that 80% of task is related with proper usage of ffmpeg command line tool, one of my priorities is minimal modification of application.

  So to make long story short, I have application which I can call directly from command line :

  stream_producer.exe CAMERA_1 

  and I want to be able to see MJPEG stream under :

  http://localhost:1234

  which can be displayed on local website in intranet.

  Regards.

• Android : How to convert WAV/PCM to another audio format without MediaCodec API

  3 octobre 2013, par khelkun

  I've searched around the web and stackoverflow during a long time about this subject. I know it has been discussed many times but I'm looking for a friendly opinion on my use case.

  I have a vocal dictation application which uses android.media.AudioRecord. It allows me to edit the recorded raw PCM buffer : insert a new record inside it, delete a certain period in the record, append a new record at the end. The result is a WAV file, but it's a bit too big file for my needs, so I want to convert it to smaller file format.

  android.media.MediaCodec could have been the solution, but it requires API level 16 which is a too high restriction in my situation.

  It sounds to me that I only have 2 options :

  1. Use the NDK and an android portage of ffmpeg like the guardian project android-ffmpeg-java. But this solution sounds a bit too hard for me so far.

  2. Recording with android.media.MediaRecorder to output an audio 3GPP file encoded with the AMR_NB encoder. Then I'll have to understand this 3GPP file header and the AMR_NB format in details to be able to perform the audio editing operations on my record.

  I must also add that creating a zip file of the WAV file is not a valid option for me.

  Does someone know another option please ? And is option 2. actually possible to achieve ?

  Thanks for your time !

• Create video with size based on image and place a video somewhere with an offset

  10 mars 2024, par NoKey

  I am trying out FFMPEG and I am unsure how hard it is to do what I want. I have some device frames and I want to play a video inside the frame. For example, this is a device frame :

  


  

  


  Now I want to play a video within the screen of the iPhone. I already got the exact X and Y offset where the video must be placed to show it correctly. I have the following challenges to make it work, and I want to make sure FFMPEG can do it before I spend to much time reinventing the wheel :

  


  


  • The output of the video must be as big as the PNG. This is already a
confusing part for me. I have the width and height already available,
but the things I saw is that FFMPEG will take over the input of the
video as final size. The final output of the video should of course
be the length of the input video.

    


  


  • The background must be transparant (so no black background, I want to
play the video on top of a website so it's nice if it's transparant and the corners are not black).

    


  


  • The ability to place a video somewhere with a specified X and Y
offset inside the device frame.

    


  


  • Not sure if it's possible in the same command, but maybe the video
needs to be resized to make it fit. I got the exact dimensions for
the video.

    


  


  


  The things I struggle most is point 1 where the output video must have a transparant background and where the device frame is placed in. Does anybody got tips ?