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• Streaming to YouTube from DJI-SDK

  6 avril 2017, par d0n13

  I’m trying to figure out how to take the camera frames in the DJI-SDK and push them to some form of encode so that I can create a live stream for YouTube.

  Has anybody got this working ? I understand most people use FFmpeg for streaming but my understanding is basic enough on how that project works.

  I’d love if somebody could share some resources on how we could go about getting this to work. I’ve seen the question on the web but I’ve found nothing that comes close to getting a solution for this.

  I need it for a project and there is a commercial solution available but it’s expensive and I can’t afford it and I’d be happy enough to code this if I can understand how to go about it and maybe get some help.

  I’d be happy enough to make an open source version of this is anyone can help.

  Thanks guys, hope we can make this...
  Donie

• FMP4 moof box sequence number ordering

  15 avril 2024, par Daniel

  I wanted to do a basic fragmented mp4 broadcast program with avformat libs and HTML5 video and MSE.

  



  This is a live stream and I use avformat to copy h264 data to mp4 fragments.

  



  Here is my basic drawing of clients attaching to the stream :

  



  

  



  So, with words :

  



  

  1. C1J : First Client joins :


     

     • avformat process starts

     


     • ftyp, moov, moof, mdat boxes will be served to Client1

     


     • ftyp and moov atoms are both saved for later reuse

     


  


  2. C2J : Second Client joins (later in time) :


     

     • avformat process is ongoing (because it is still serving moof and mdat boxes for Client1)

     


     • previously saved ftyp and moov boxes will be served first to Client2

     


     • after ftyp and moov boxes were served, Client2 will join to the stream at the next moof box.

     


  


  



  I have saved an mp4 file to disk from both clients.

  



  Atoms' order within both files looks good : ftype, moov, moof, mdat, moof, mdat...

  



  Both files can be played by media players (like VLC) and also in browsers directly (Opera).

  



  Client1 can be played also via MSE in the browser (Opera), but Client2's stream is not displaying with MSE (Opera).

  



  No errors on the JS console, and media-internals looks also good (at least equivalent with Client1's one).

  



  Now I realized that every moof box contains an mfhd box (header) with a sequenceNumber field.

  



  Of course in Client1's first moof box this sequenceNumber is 1.
However in the later joined Client2's first moof box this sequenceNumber is always >= 1 (in my case it is 16).

  



  What do I need to modify in the moof boxes in Client2 to have a valid fmp4 from the beginning ?

  



  I think Opera's HTML5 video does not like if sequenceNumber does not start from 1, but there shall be other requirements for being it valid.

  


• How to create side by side horizontally stacked video with delay in video and audio using ffmpeg-python ?

  29 juillet 2021, par kup

  I am trying to create a video from two videos that will be stacked horizontally but the resulting video is not what i expected. The same video is appearing on both side (left & right). So wondering how that can be achieved ?

  


  The ffmpeg command i tried, which kinda worked :

  


  ffmpeg -i left.mp4 -i right.mp4 -filter_complex "
[0:v]setpts=PTS-STARTPTS[l]; 
[1:v]setpts=PTS-STARTPTS,tpad=start_duration=14:start_mode=add:color=black[r]; 
[l][r]hstack=inputs=2[stacked]; [0:a][1:a]amix=inputs=2[a]
" -map "[stacked]" -map "[a]" -c:a aac -preset superfast result.mp4


  


  ffmpeg-python script that's not working :

  


  in0 = ffmpeg.input('0.mp4')
in1 = ffmpeg.input('right.mkv')
aout = ffmpeg.filter([in0.audio, in1.audio.filter('adelay', "5000|5000")],'amix')
vout = ffmpeg.filter([inv0.video, inv1.video.filter('tpad', start_duration=5, start_mode='add', color='black')], 'hstack')

(
    ffmpeg
    .concat(vout, aout, v=1, a=1)
    .output("out.mkv")
    .run()
)


  


  This script not resulting in the expected output which two videos side-by-side horizontally stacked.