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• How to plot animated time series in R ?

  28 août 2016, par pOrlando

  I am trying use the ’animation’ package in R to plot an animated time series.

  My dataset consists of a time vector and a value vector, each with 1800 rows.

  I keep getting an error message after running the loop which reads :

  Error in jpeg(gname[i]) : unable to start jpeg() device
  
  In addition: Warning messages:
  
  1: In jpeg(gname[i]) : unable to open file 'g11:30:00.jpg' for writing
  
  2: In jpeg(gname[i]) : opening device failed

  Here’s the source code

  timemax<-1800
  
  setwd("~/Documents/Animation/")
  
  graphdata<-read.csv("filling_line_data_construction_v2.csv")
  
  attach(graphdata)
  
  gname<-paste("g",time, ".jpg", sep="")
  
  for (i in 1:timemax){
  
      jpeg(gname[i])
  
      plot(time[1],value[1],type="l",ylim=c(0,35), xlim=c(0,100),
  
        ylim = c(0, 35),ylab = "", xlab="time")
  
      lines(time[1:i],value[1:i])
  
      dev.off(dev.cur())
  
  }

  The end goal is to string together these 1800 plots as a stop animation video by calling the ffmpeg shell :

  shell("C:/ffmpeg/bin/ffmpeg.exe -report -i g%d.jpg -b:v 2048k fillin_lineR.mpg",mustWork=FALSE)

  This is code that I’ve been trying to adapt from http://www.animatedgraphs.co.uk/LondonR.html#slide-30, but this example uses a .tif file instead of .jpg, and my computer gives me 1800 error messages when trying to make a video from .tif files...

  Thanks in advance !

• FFmpeg -segment with a lot of time codes

  24 février 2020, par Grenight

  I’m making program that splits videos for running parallel encodes.

  My problem is that with putting all segments into command like i can hit a limit of maximum characters in windows console. Approximately 600, while 1-2 hour movie can easily be 1000-2000 scenes.

  Is there a way to use .csv file for segment so i don’t need to put all time codes to command line ? Or is there another ways ?

  Here is example of command line that is used in program :
  timecodes is where all time codes passed.

  cmd = f'{self.FFMPEG} -i {video} -map_metadata 0 -an -f segment -segment_times {timecodes} -c copy -avoid_negative_ts 1 {self.temp_dir / "split" / "%04d.mkv"}

• filter_complex command taking too much processing time

  5 septembre 2016, par Atiq Ur Rehman

  i am using FFMPEG for adding watermark on video in Android application.
  String cmd = "-i " + path + " -i " + png + " -filter_complex overlay=10:main_h-overlay_h-10 -threads 5" + " -preset ultrafast -strict -2 " + outputPath

  i am using this command to add watermark, this command is working but taking too much time, it takes 60 second to process 10 second video approx.

  is that any solution to reduce the processing time.

  Thanks