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• FFMPEG/FFPLAY Dual screen with live RTMP Filter

  28 février 2016, par Dennis Bijsterveld

  What I’m trying to do is getting a RTMP input and apply 2 filters to the same input source and having them next to eachother. To check both EBUR128 levels and waveforms. Problem that I’m getting is that I can’t mix them together.

  Filters :
  EBU R128 (I would love to have a graphical EBU R128 meter.)
  Example :

  ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18
  [out0][out1]"

  And a waveform to check broadcast levels.

  ffplay -i http://download.blender.org/peach/bigbuckbunny_movies/big_buck_bunny_480p_surround-fix.avi -vf "split[a][b] ;[a]format=gray,waveform,split[c][d] ;[b]pad=iw:ih+256[padded] ;[c]geq=g=1:b=1[red] ;[d]geq=r=1:b=1,crop=in_w:220:0:16[mid] ;[red][mid]overlay=0:16[wave] ;[padded][wave]overlay=0:H-h"

• Empty output when extracting frames with FFMPEG at specific timestamps taken from FFPROBE

  9 octobre 2023, par Andrew McDowell

  I am trying to extract frames from a video as close as possible to specific timestamps, but for some timestamps I'm getting no output.

  


  I'm first using ffprobe to get a list of all frames along with their time values :

  


  ffprobe -select_streams v -show_frames -show_entries frame=pts_time,pkt_pts_time,pict_type <input video="video" />

  


  Which gives me an output like :

  


  [FRAME]
pts_time=11.950000
pict_type=I
[/FRAME]
[FRAME]
pts_time=11.966667
pict_type=B
[/FRAME]
[FRAME]
pts_time=11.983333
pict_type=P
[/FRAME]


  


  I'm then parsing this and determining which frame is the closest to the time I want and using FFmpeg to extract frames which match the chosen times like so :

  


  ffmpeg -i <input video="video" /> -filter:v "select=&#x27;eq(t, 11.950000)&#x2B;eq(t, 11.983333)&#x27;" -vsync drop -start_number 0 <output path="path">/frame-%08d.png</output>

  


  This mostly works but I've noticed for some frames I get no output. From some testing it always seems to work for I frames and works occasionally for P or B frames but not always.

  


  I can't see any pattern to which frames it works for or not and would love an insight into whether I'm doing something wrong in the extraction, or whether there's a way to determine which frames can be extracted or not.

  


• ffmpeg audio convert not working

  11 janvier 2012, par Andrew

  I cannot get the ffmpeg audio convert working on my site. The idea is that file should be converted when it's uploaded on the site.

  I've got this on my upload form determining the audio file's format :

  if(isset($_POST['audio']) && $_POST['audio'] != ''){
  
                  $ext1 = substr($_POST['audio'], -4);

  This is the best I've come up with for converting m4a to mp3 :

  if(isset($_POST['audio']) && $_POST['audio'] != ''){ $file = $_POST['audio'];     if($ext1==".m4a"){ $call="/usr/local/bin/ffmpeg -i ".$file." -ab 192k -f -acodec mp3";}
  
  $convert = (popen("start /b ".$call, "r")); pclose($convert);

  The problem is, it won't convert. The path to ffmpeg is correct.

  Now I may be way over my head with this one, but if there's a simple solution for this, I'd love to hear it.

  EDIT.

  With this :

  if(isset($_POST['audio']) && $_POST['audio'] != ''){
  
      $file = $_POST['audio'];
  
                      $ext1 = substr($_POST['audio'], -4); /*get the last 4 chars*/
  
                      $mp3 = echo 'mp3';
  
  if($ext1=".m4a"){ 
  
  "/usr/local/bin/ffmpeg -i \"". $file . "\" -ab 192k -y -f mp3 \"".ext1.$mp3."\"";
  
  }
  
  }

  I think I'm right on the money with conversion itself, but the form just loads infinitly when submitted. So I'm guessing the conversion is happening, but the form does not know when it's done. Any ideas on that ?