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• FFmpeg Keeps Outputting 4:3 aspect ratio - No Idea Why

  11 janvier 2020, par John Doe

  This command will produce a 1920x1080 video, however there are borders on the left and right, making it appear 4:3 rather than the proper 16:9, and also warps/stretches the overlays. I have checked (and rechecked) my input files and they’re all 1920x1080. This is such a silly problem and I feel like I’m missing something obvious.

  ffmpeg -y -f concat -i "concat.txt" -i "mask.png" -i "audio.mp3" -filter_complex "[0]scale=3840x2160,zoompan=z='if(lte(zoom,1.0),1.2,max(1.001,zoom-0.0010))':x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':fps=15:d=200[p];[p][1]overlay,drawtext=fontfile=Heathergreen.otf:text='Testing':fontcolor=black:fontsize=32:x=140:y=950[v];[2:a]showwaves=mode=cline:s=178x56:r=15:scale=sqrt:colors=0x222222,colorkey=0x000000:0.01:0.1,format=yuva420p[w];[v][w]overlay=108:740,scale=1920:1080[outv]" -map "[outv]" -map 2:a -c:v libx264 -c:a aac -preset ultrafast -shortest "output.mp4"

• checkasm/riscv : test misaligned before V

  21 mai 2024, par Rémi Denis-Courmont

  checkasm/riscv : test misaligned before V
  Otherwise V functions mask scalar misaligned ones.
  

  • [DH] tests/checkasm/checkasm.c

• How to stop perl buffering ffmpeg output

  4 février 2017, par Sebastian King

  I am trying to have a Perl program process the output of an ffmpeg encode, however my test program only seems to receive the output of ffmpeg in periodic chunks, thus I am assuming there is some sort of buffering going on. How can I make it process it in real-time ?

  My test program (the tr command is there because I thought maybe ffmpeg’s carriage returns were causing perl to see one big long line or something) :

  #!/usr/bin/perl
  
  
  
  $i = "test.mkv"; # big file, long encode time
  
  $o = "test.mp4";
  
  
  
  open(F, "-|", "ffmpeg -y -i '$i' '$o' 2>&1 | tr '\r' '\n'")
  
          or die "oh no";
  
  
  
  while(<f>) {
  
          print "A12345: $_"; # some random text so i know the output was processed in perl
  
  }
  
  </f>

  Everything works fine when I replace the ffmpeg command with this script :

  #!/bin/bash
  
  
  
  echo "hello";
  
  
  
  for i in `seq 1 10`; do
  
          sleep 1;
  
          echo "hello $i";
  
  done
  
  
  
  echo "bye";

  When using the above script I see the output each second as it happens. With ffmpeg it is some 5-10 seconds or so until it outputs and will output sometimes 100 lines each output.

  I have tried using the program unbuffer ahead of ffmpeg in the command call but it seems to have no effect. Is it perhaps the 2>&1 that might be buffering ?
  Any help is much appreciated.

  If you are unfamiliar with ffmpeg’s output, it outputs a bunch of file information and stuff to STDOUT and then during encoding it outputs lines like

  frame=  332 fps= 93 q=28.0 size=     528kB time=00:00:13.33 bitrate= 324.2kbits/s speed=3.75x

  which begin with carriage returns instead of new lines (hence tr) on STDERR (hence 2>&1).