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• zoompan filter creates shaky image ?

  26 avril 2016, par user2126005

  I try to perform a basic zoompan with FFmpeg. I have an input list image (.jpg 400x300) and i create slice image video (.mp4 400*300) from it, with a zoom each image. This is my command :

   ffmpeg -y -loop 1 -i image01.jpg -loop 1 -i image02.jpg -loop 1 -i image03.jpg  -filter_complex "
  
   [0:v]zoompan=z='min(zoom+0.0015,1.5)':x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':d=400 ,trim=duration=5,fade=t=in:st=0:d=0.5,fade=t=out:st=4.5:d=0.5,scale=400*300,setpts=PTS-STARTPTS[v0]; 
  
   [1:v]zoompan=z='min(zoom+0.0015,1.5)':d=125,trim=duration=5,fade=t=in:st=0:d=0.5,fade=t=out:st=4.5:d=0.5,scale=400*300,setpts=PTS-STARTPTS[v1]; 
  
   [2:v]zoompan=z='min(zoom+0.0015,1.5)':d=125,trim=duration=5,fade=t=in:st=0:d=0.5,fade=t=out:st=4.5:d=0.5,scale=400*300,setpts=PTS-STARTPTS[v2]; 
  
   [v0][v1][v2] concat=n=3:v=1:a=0, format=yuv420p[v]" -c:v libx264 -map "[v]"  output_no_audio.mp4

  Everything works...but the zoom is not looking okay. It is going zig-zag (the first image scale from center, remaining part is scale default)

  i’ve already consulted this link. But it inapplicable to this situation.

  Does anyone know how to make it zoom smooth and explain how to calculate ?

  thank in advance !

• RMS Normalize ffmpeg

  23 juin 2016, par steve

  I’m new to ffmpeg and would like to create a script that can RMS normalize audio files to a specified RMS (mean) dB level. Can someone show how to do this ?

  I’ve used dynaudnorm, but can’t get the desired output, I believe it’s due it using frames opposed to analyzing the full file.

  To RMS normalize, my thought is to use a conditional statement to create a filter that can automatically read RMS (mean) level of an audio file and then automatically set the RMS (mean) level to a specified dB level.

  Theoretical example :

  ffmpeg -i (inputfilename) -af "normalize_rms=-20dB" (outputfilename)

  Explanation of Conditional Statement and Example :

  • Pass 1 : run astats or volumedetect to calculate RMS level.

  • Pass 2 : If RMS level = X dB, then add Y dB level to match the user specified dB level.
    Example : If RMS level = -30dB, and user specified RMS level = -20dB, then add 10dB.

• PSNR for YUV files using matlab [duplicate]

  29 février 2016, par apiproj

  This question already has an answer here :

  • Power Signal Noise Ratio (PSNR) of colored jpeg image [closed]
    
    2 answers
    

  In my video streaming application I have two yuv files.One is original which is am streaming over the network after x264 encoding, another is reconstructed decoded yuv file in receiver side.

  How to calculate PSNR value between two YUV files in MATLAB or ldecoder or using any other tool ?

  Thanks in advance.