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• Issues with adding the current timestamp of a video when using FFPLAY

  28 janvier 2023, par lalelarsen1

  Hi i am trying to add to display the current time of the video as an overlay. i have tried to do follow the answer of this previous post : https://superuser.com/questions/968685/how-to-display-current-time-with-the-ffplay-exe but with no luck.

  


  This is my line of code :

  


  "./ffmpeg-2023-01-25-git-2c3107c3e9-full_build/bin/ffplay.exe" -vf "drawtext=fontfile=./consola.ttf:text='%{pts:hms}':fontsize=48:fontcolor=white:box=1:boxborderw=6:boxcolor=black@0.75:x=(w-text_w)/2:y=h-text_h-20" -i "%shadowplays_folder%\%NEWEST_FOLDER%\%NEWEST_FILE%" -autoexit -x "1000" -alwaysontop


  


  This will display the text "hms}" not the time.

  


  the above code works fine if i replace it with a simple string :

  


  "./ffmpeg-2023-01-25-git-2c3107c3e9-full_build/bin/ffplay.exe" -vf "drawtext=fontfile=./consola.ttf:text='test':fontsize=48:fontcolor=white:box=1:boxborderw=6:boxcolor=black@0.75:x=(w-text_w)/2:y=h-text_h-20" -i "%shadowplays_folder%\%NEWEST_FOLDER%\%NEWEST_FILE%" -autoexit -x "1000" -alwaysontop


  


  This will display the text "test"

  


  what am i missing ?

  


• av::av_encode_video produces blurred video from crisp files

  9 janvier 2023, par Abdirizak

  I am using the av::av_encode_video() function to produce a .mp4 video from png files, as in this answer. I pay special attention for the png files to be perfectly crisp, i.e. I plot matrices to png with exactly the same dimensions, so that every matrix cell maps to one cell in the png. Here is code to illustrate what I mean :

  


  library(av)

n.times <- 24*10
n.row <- 50
n.col <- 26

out.dir <- "/Users/Abdirizak/Documents/some/directory/"

for (i in 1:n.times) {
   
   current.mat <- matrix(data = rnorm(n.row*n.col), nrow = n.row, ncol = n.col)
   
   setwd(out.dir)
   png(filename = paste0(i, ".png"), width = n.row, height = n.col)
   
   par(mar = rep(0,4))
   image(current.mat)
   
   dev.off()
   
}

setwd(out.dir)
png.files <- paste0(out.dir, list.files(pattern = ".png$"))

av::av_encode_video(input = png.files, output = "000.mp4", framerate = 24)


  


  Now, even though my input .png files are perfectly crisp, the output .mp4 video is blurry. How can I prevent that from happening ? I.e. how can I get a perfectly crisp video ? (I am aware that this will likely inflate the file size of the .mp4 file)

  


  I already digged a bit into the vfilter argument of av_encode_video() and the underlying ffmpeg filter graphs on here, but could not yet really get the hang on it.

  


  I am looking at the .mp4 file through QuickTime Player on MacOS Ventura 13.0.1, and using R version 4.2.2 through RStudio 2022.12.0.353

  


  Edit 9.1.2023 :

  


  To further clarify, here is an example screenshot of a png image (not the original png file because that one appears too small here) :

  


  

  


  As I said, a perfectly crisp image.

  


  On the other hand, a screenshot of the .mp4 movie looks like this :

  


  

  


  Somewhat unsatisfactory. Any suggestions are welcome.

  


• Add date of creation to the metadata title in ffmpeg

  13 mai 2023, par Louis Did

  I record a live radio stream 3 times a week and would like to be able to add the date of the recording/creation time to the metadata title using ffmpeg. I want to see the title of the show with date of the recording on it when I play the mp3 file. For example : the title displayed on the player will be like this : Nocturnes 5-13-2023.

  


  I have tried the following :

  


  ffmpeg -i https://medfm.net/live/medfm.mp3 -t 00:05:00.00 -metadata title="Nocturnes $(date +%m-%d-%Y)" -c copy -f segment -strftime 1 -segment_time 3200 Nocturnes_%Y_%m_%d.mp3