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• Poor video quality in first few frames using video output options in gganimate

  27 janvier 2021, par Nautica

  I'm trying to export some animations I've made using gganimate through video format as the gifs I'm creating are quite large.

  


  Sample code :

  


  library(gganimate)

p <- ggplot(mtcars, aes(factor(cyl), mpg)) +
  theme_dark() +
  theme(panel.grid = element_line(colour = "white")) +
  geom_boxplot() +
  transition_states(
    gear,
    transition_length = 2,
    state_length = 1
  ) +
  enter_fade() +
  exit_shrink() +
  ease_aes('sine-in-out')

anim_save("example.mp4",
          animate(
            p,
            nframes = 450,
            fps = 25,
            width = 1280,
            height = 720,
            type = "cairo",
            start_pause = 50,
            end_pause = 50,
            renderer = av_renderer()
          ))


  


  Produces the video seen here : https://vimeo.com/505019987

  


  With the standard ggplot2 theme : https://vimeo.com/505020822

  


  This is another example of something I made using gganimate : https://www.youtube.com/watch?v=fHzjl_z_sSo

  


  You can see that the video quality in the first few frames are very bad. In the video with the standard ggplot2 theme and the YouTube video, the gridlines and watermark text are not visible at the start but fade in much later. I don't know much about video codecs but I assume it has something to do with the ffmpeg library the av package/av_renderer() is using. Has anyone experienced something like this ?

  


• ffmpeg settings for high quality youtube videos [migrated]

  1er avril 2018, par pb.

  I am trying to record short video of my desktop and upload it to youtube.
  The problem is that every time when I upload it to youtube or even dropbox (as video), the quality is much worse.

  My ffmpeg execution :

  ffmpeg -f x11grab -s 1366x768 -r 30 -i :0.0 -codec:v libx264 -crf 10 -bf 20 -flags +cgop -pix_fmt yuv440p -movflags faststart help.mp4

  based on :

  ffmpeg -i <input file="file" /> -codec:v libx264 -crf 21 -bf 2 -flags +cgop -pix_fmt yuv420p -codec:a aac -strict -2 -b:a 384k -r:a 48000 -movflags faststart .mp4

  which I found here

  Original file (.zip) :
  https://www.dropbox.com/s/xlkr83rkqfxon23/help.mp4.zip?dl=0

  File after upload to youtube :
  https://www.youtube.com/watch?v=ewEUgpXOpmg

  As you can see, I loss quality after upload to youtube.

  Could you help me ?
  How should I choose the appropriate parameters to record and upload high quality video ?

• ffmpeg settings for high quality youtube videos [migrated]

  1er avril 2018, par pb.

  I am trying to record short video of my desktop and upload it to youtube.
  The problem is that every time when I upload it to youtube or even dropbox (as video), the quality is much worse.

  My ffmpeg execution :

  ffmpeg -f x11grab -s 1366x768 -r 30 -i :0.0 -codec:v libx264 -crf 10 -bf 20 -flags +cgop -pix_fmt yuv440p -movflags faststart help.mp4

  based on :

  ffmpeg -i <input file="file" /> -codec:v libx264 -crf 21 -bf 2 -flags +cgop -pix_fmt yuv420p -codec:a aac -strict -2 -b:a 384k -r:a 48000 -movflags faststart .mp4

  which I found here

  Original file (.zip) :
  https://www.dropbox.com/s/xlkr83rkqfxon23/help.mp4.zip?dl=0

  File after upload to youtube :
  https://www.youtube.com/watch?v=ewEUgpXOpmg

  As you can see, I loss quality after upload to youtube.

  Could you help me ?
  How should I choose the appropriate parameters to record and upload high quality video ?