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• FFMPEG how to record aac codec audio same time with wideo ?

  12 décembre 2017, par Gomi Odabaşıoğlu

  I am trying to use FFMPEG console tools effectively. Now I can record video and audio same time but my issue is audio is delaying. I use following code :

  C:\Users\gomid_000\Desktop\ffmpeg.exe -y -f dshow -i audio="Stereo Mix (Realtek High Definition Audio)" -f gdigrab -show_region 1 -framerate 60 -i desktop -map 0 -map 1 -c:v libx264 -preset ultrafast -pix_fmt yuv420p C:\Users\gomid_000\Desktop\out.mp4 -threads:1 4

  I do not know if I can automatically sync them together and prevent delay. Is it better to use AAC codec ? If it is how can I do that ?

• Record UDP stream with ffmpeg video+klv-data

  26 septembre 2017, par mfreiholz

  I’d like to record an MPEGTS UDP stream with ffmpeg binary to disk.

  This works in a stable network :

  ffmpeg.exe -i "udp://224.10.10.10:15006?multicast=1&timeout=360000000&reuse=1" -f mpegts -map 0:0? -map 0:1? -map 0:2? -c copy "C:/test.ts"

  The entire stream is saved to test.ts.

  Live Environment

  In my live environment it is possible that the connection is very bad or is not available at all (cable disconnect, device reboot, ...) for a few minutes. I want ffmpeg to simply continue writing upcoming frames to *.ts file. I don’t need the lost frames.

  Currently the following errors appears, if there was a too long brake between UDP frames :

  [mpegts @ 00000000003cf920] Application provided invalid, non monotonically increasing dts to muxer in stream 1: 11606399 >= 2084534
  
  av_interleaved_write_frame(): Invalid argument

  It looks like to be a problem with the timestamp. My idea would be to tell FFMPEG to ignore those errors and simply continue.

  Is it even possible with the ffmpeg binary or do I have to solve the problem with a custom C/C++ implementation using the library ?

  Thank you

  Update 1

  If I only record the video stream -map 0:0? and not the others it seems to work. Looks like the problem is associated with the second stream (No.1) which is KLV encoded data.

• Best way to record a HTML Canvas/WebGL animation server-side into a video ?

  19 novembre 2022, par Abhinav

  I have a set of animations which I can make in Canvas (fabric.js) or WebGL (three.js). I need to record them automatically, server-side, through a script and output a video file.

  



  The animations include :
  

  



  

  1. Pictures
     

  


  2. Videos (with audio)
     

  


  3. Other animations/effects

  


  



  I have researched a lot during last few months on this.

  



  Results
  
1. Use PhantomJS + FFMPEG
  
Run HTML Canvas animations on headless browser(PhantomJS) and record with FFMPEG. Here the issue is PhantomJS supports neither WebGL nor Video element. http://phantomjs.org/supported-web-standards.html

  
2. Use Websockets to send data back to server using DataURL
  
Here again, we will need to run the animations on browser (which we can't because we have to do everything on server).

  
3. Use node-canvas
  
This is a library by TJ Holowaychuk which allows rendering HTML Canvas on Node.js. But it has its own limitations plus I haven't really explored this field much. 
(If someone could shed more light on this library)

  



  If anyone has done it before or can guide me somewhere useful.
  
All we need to do is use some data to create animations and record it into a video, everything on server side.