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• Why can I not change the number of frames (nframes) in a gganimate animation ?

  26 décembre 2022, par Gekin

  I have produced an animation per gganimate and rendered it per ffmpeg. It works just fine, but only, if I do not change the number of frames. If I do set the number of frames, I get this error message :

  


  nframes and fps adjusted to match transition
Error parsing framerate 8,4.                           
Error: Rendering with ffmpeg failed


  


  I produced the gganim MonthlyAveragePrecipitationMap the following way :

  


  options(scipen = 999, OutDec  =  ",")

MonthlyAveragePrecipitationMap = ggplot(MonthlyAverageExtremePrecipitation) + 
  geom_path(data = map_data("world","Germany"),
            aes(x = long, y = lat, group = group)) +
  coord_fixed(xlim = c(6,15),
              ylim = c(47,55)) + 
  geom_point(aes(x=lon, y=lat, 
                 colour = ShareOfExtremePrecipitationEvents,
                 group = MonthOfYear),
             size = 3) + 
  scale_color_gradient(low="blue", high="yellow") + 
  xlab("Longitude (degree)") +
  ylab("Latitude (degree)") + 
  theme_bw() +
  transition_manual(frames = MonthOfYear) + 
  labs(title = '{unique(MonthlyAverageExtremePrecipitation$MonthOfYear)[as.integer(frame)]}', 
       color = paste0("Share of Extreme Precipitation Events \namong all Precipitation Events")) 


  


  I call the animation the following way :

  


  animate(MonthlyAveragePrecipitationMap,
        nframes = 300,
        renderer =
          ffmpeg_renderer(
            format = "auto",
            ffmpeg = NULL,
            options = list(pix_fmt = "yuv420p")))



  


  I used this exact code just a few days ago and it worked fine.

  


  Has someone had similar experiences ?
Thanks in advance.

  


• ffmpeg map and filter_complex subprocess in python

  4 décembre 2015, par jlarsch

  I want to crop and re encode videos via ffmpeg from within python using subprocesses.

  I managed starting a subprocess using a pure string command and shell=True but I want to build more complex commands and would prefer to use shell=False and passing a list of arguments.

  So what works is this form (this is a simplified example, there will be multiple streams in the final version) :

  import subprocess as sp
  
  
  
  sp.Popen('ffmpeg.exe -i Test.avi -filter_complex "[0:v]crop=1024:1024:0:0[out1]" -map [out1] out1.mp4', shell=True)

  This script produces the expected cropped output video.

  For a list of arguments, I tried :

  FFMPEG_PATH = 'ffmpeg.exe'
  
  aviP='Test.avi'
  
  sp.Popen([FFMPEG_PATH,
  
  '-i', aviP,
  
  '-filter_complex', '[0:v]crop=1024:1024:0:0[out1]',
  
  '-map', '[out1] out1.mp4'])

  When I execute this second version, simply nothing happens. (no error, no output)

  I suspect I am messing up something in the map command syntax ?

• Ffmpeg map and filter_complex subprocess - Python

  4 décembre 2015, par jlarsch

  I want to crop and re encode videos via ffmpeg from within python using subprocesses.

  I managed starting a subprocess using a pure string command and shell=True but I want to build more complex commands and would prefer to use shell=False and passing a list of arguments.

  So what works is this form (this is a simplified example, there will be multiple streams in the final version) :

  import subprocess as sp
  
  
  
  sp.Popen('ffmpeg.exe -i Test.avi -filter_complex "[0:v]crop=1024:1024:0:0[out1]" -map [out1] out1.mp4', shell=True)

  This script produces the expected cropped output video.

  For a list of arguments, I tried :

  FFMPEG_PATH = 'ffmpeg.exe'
  
  aviP='Test.avi'
  
  sp.Popen([FFMPEG_PATH,
  
  '-i', aviP,
  
  '-filter_complex', '[0:v]crop=1024:1024:0:0[out1]',
  
  '-map', '[out1] out1.mp4'])

  When I execute this second version, simply nothing happens. (no error, no output)

  I suspect I am messing up something in the map command syntax ?