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• How to introduce artificial noise in the videos using ffmpeg ?

  17 juin 2021, par ashish14

  I am trying to introduce artificial noise in the videos so as to simulate real-world behaviour. The sources of noise I am currently considering are :

  


  

  1. Quality of video

     

     • Modifying video properties such as frame rate, resolution, bit rate, codecs and compression.

     


     


  


  2. Recording Conditions

     

     • Factors such as lighting, brightness, contrast, darkness, blurriness, color etc.

     


     


  


  


  So far I have tried changing the brightness to replicate different lighting settings. I used this command
ffplay -vf eq=gamma=1.5:brightness=0.3:saturation=20 P2_Frontal_3_A.MP4 to change the values of brightness.

  


  Questions :

  


  

  • Does modifying the brightness like above make sense to simulate different lighting conditions ?

  


  • What other properties should I change for blurriness, contrast and darkness ?

  


  


• sdp : Simplify parsing/conversion of H264 extradata

  3 octobre 2014, par Martin Storsjö

  sdp : Simplify parsing/conversion of H264 extradata
  By using ff_avc_write_annexb_extradata instead of the h264_mp4toannexb
  
  BSF, the code for doing the conversion itself is kept much shorter,
  
  there’s less state to restore at the end, we don’t risk leaving the
  
  AVCodecContext in an inconsistent state if returning early due to
  
  errors, etc.
  Also add a missing free if the base64 encoding fails.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavformat/sdp.c

• NodeJS piping with ffmpeg

  8 février 2014, par Gnap

  I wanted to do a HTTP live stream on a screen cast with using ffmpeg, nodejs and html5 . I wanted it to be as real time as possible. However, I find that my video received by the client was behind by 1 2 seconds (On Chrome/Chromium). I am using vp8/webm as my codec.

  I have eliminated the following factors as such :
  1) Network : I have tried serving and receiving the video file locally by stating the video source to be 127.0.0.1:PORT or localhost:PORT
  2) ffmpeg encoding speed:I have tried outputting the file locally, it the "delay" seems to be negligible.
  3) Chrome internal buffer. The buffer was accounted to be 0.07s 0.08s.

  On the nodeJS side, I have a child process that runs the ffmpeg command, and did a ffmpeg.stdout.pipe(res) ; <— ffmpeg is child_process.spawn(...)

  So it seems that the ffmpeg.std.pipe(res) of nodejs seems to be the one delaying the video stream. Am I correct in assuming so ? Is there anyway that I may reduce the delay ?