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• 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


  


• What would be the correct way to use Exec or Transcode ffmpeg in SRS version of Windows 5.0.128

  29 janvier 2023, par diegosn79

  i was doing tests in different ways, and i can't use the Exec or Transcode option, i highlight that I have copied the ffmpeg.exe in the objs folder.
These are the codes I tried, and I attach the log errors.

  


  exec {

enabled on;

publish ./objs/ffmpeg.exe -rtbufsize 10M -i rtmp://10.1.9.240/live/encoder  -vf scale=1080:720 -c:v libx264 -profile:v high -level 4.2 -preset fast -b:v 1500k -c:a aac -ac 2 -b:a 96k -f flv -y rtmp://10.1.9.240:1935/live/encoderlow/;

}


  


  LOGS

  


  [2023-01-04 10:05:46.410][WARN][1309][01568ctu][11] EXEC : Ignore error, code=3028(FFmpegFork)(Failed to fork FFmpeg trancoder process) :
process start : vfork process failed, cli=./objs/ffmpeg.exe -rtbufsize 10M -i rtmp ://10.1.9.240/live/encoder -vf scale=1080:720 -c:v libx264 -profile:v high -level 4.2 -preset fast -b:v 1500k -c:a aac -ac 2 -b:a 96k -f flv -y rtmp ://10.1.9.240:1935/live/encoderlow/
thread [1309][01568ctu] : do_cycle() [./src/app/srs_app_ng_exec.cpp:108][errno=11]
thread [1309][01568ctu] : start() [./src/app/srs_app_process.cpp:197][errno=11]

  


  transcode

  


      enabled     on;

    ffmpeg      ./objs/ffmpeg.exe;

    engine ff {

        enabled         on;

        vfilter {

        }

        vcodec          libx264;

        vthreads        4;

        vprofile        high;

        vpreset         fast;

        vbitrate        1500k;

        vparams {

        }

        acodec          libfdk_aac;

        aparams {

        }

        output          rtmp://127.0.0.1:[port]/[app]/[stream]_[engine]?vhost=[vhost];

    }

}


  


  LOGS

  


  [2023-01-04 11:04:45.295][WARN][1489][34r32764][11] Encoder : Ignore error, code=3028(FFmpegFork)(Failed to fork FFmpeg trancoder process) : ffmpeg start : vfork process failed, cli=./objs/ffmpeg.exe -f flv -i rtmp ://127.0.0.1:1935/live ?vhost=defaultVhost/encoder -vcodec libx264 -b:v 1500000 -threads 4 -profile:v high -preset fast -acodec libfdk_aac -f flv -y rtmp ://127.0.0.1:1935/live/encoder_ff ?vhost=defaultVhost 1 > ./objs/ffmpeg-encoder-defaultVhost-live-encoder-ff.log 2 > ./objs/ffmpeg-encoder-defaultVhost-live-encoder-ff.log
thread [1489][34r32764] : do_cycle() [./src/app/srs_app_encoder.cpp:117][errno=11]
thread [1489][34r32764] : start() [./src/app/srs_app_process.cpp:197][errno=11]