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• FFMPEG waveform transparent, background solid color

  11 mai 2016, par user1152226

  I am trying to generate a waveform with ffmpeg, I want the background to be a solid color, and the actual waveform to be transparent. The following achieves partially what i want, except that in has a black background. I would like to be able to change this to any color, but have the waveform be transparent. How can i achieve this with ffmepg ?

  ffmpeg -i input.mp3 -filter_complex \
  
  "[0:a]aformat=channel_layouts=mono,\
  
  compand=gain=-6, \
  
  showwavespic=s=600x120, \
  
  colorchannelmixer=rr=1:gg=0:bb=0:aa=1,\
  
  drawbox=x=(iw-w)/2:y=(ih-h)/2:w=iw:h=1:color=red,\
  
  format=rgba,\
  
  colorkey=#ff0000" \
  
  -vframes 1 output.png

  This generates this waveform : the background is black, the waveform itself is transparent. How do I change the background color to a different color, while still keeping the waveform transparent ?

  

• Révision 19184 : Dans un cas où le serveur est configuré avec un expire sur text/html, le privé e...

  30 mars 2012, par kent1 -

  cf le message de marcimat là http://technique.arscenic.org/lamp-linux-apache-mysql-php/apache/optimisations/article/expire-headers#forum168 dont j’ai eu l’expérience aussi Autant l’éviter si possible ici

• There is a problem with converting ffmpeg video from hev1 to hvc1

  18 septembre 2024, par sixawnstar

  ffmpeg -i in.mp4 -c:v copy -c:a copy -tag:v hvc1 out.mp4

  


  I used ffmpeg to transcode the videos, but some of the transcoded videos were black screens with audio but no visuals.

  


  enter image description hereenter image description here

  


  By using ffmpeg -i video.mp4 to view the video information, it was found that the information for both videos is consistent. However, the screen in Figure 1 displays a black screen after transcoding, whereas Figure 2 functions normally after transcoding.