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• Using only ffmpeg, is it possible to consume a source GIF image and output a video that is a set length > one loop through the input GIF ?

  23 octobre 2013, par Thomas Graft

  Let's say I have an 8 frame animated GIF that is 2 seconds long. I would like to build a video file (codec not important at this point) that is 30 seconds long that consists of the source GIF repeating over and over.

  Is it possible to do this using only ffmpeg ? Answers that use convert or some other pre-processing utility do not count [The reason being that I would like to use this on PandaStream, which does not have that utility]. Let's also assume that shell scripts are out of the question as well, though it can be multiple ffmpeg commands.

  ---

  Things I have tried that did not work (though maybe I did them wrong, I'm not terribly familiar with ffmpeg) :

  1. Using the -loop_input, -loop_output options present in the ffmpeg docs. Using both ffmpeg 1.2 and 2.0, I get a Unrecognized option 'loop_[input|output]' error message. I might be using this wrong though since the error is about not recognizing the option, though the docs say it is deprecated.

  2. -loop option. Does not seem to do anything with GIF -> Video. I think this flag and the above flag are related to generating animated GIFs as the output.

  3. Concat. Doing something like :

     ffmpeg -i "concat:image.gif|image.gif|image1.gif|image2.gif|image3.gif|image4.gif" image-long.gif

     Results in a 16 frame gif (so two gifs are concatenated) which is progress, though the output gif is of much lower quality.

  ---

  I'm a bit at my wits end here (I have tried many other permutations of the above concepts), I'm at the point now of 'poking it with a stick', hopefully someone out there has done this !

• Can ffmpeg transcode an audio track and add it as a second audio track at the same time, or if not, how to do it as separate commands ?

  31 mai 2020, par wb6vpm

  A bit of history. I am using Plex as my media server, but for reasons unknown, it has issues transcoding the DTS-HD MA 7.1 audio to EAC3 stereo and keeps buffering (the server has plenty of horsepower on all fronts, CPU/RAM/drive space & speed, gigabit networks connections for all devices. The playback device (TCL Roku TV, with a 3rd party soundbar connected via HDMI ARC) doesn't support the built-in 7.1 audio, so I get silence if I play it back directly by putting the file on a USB stick.

  



  Also, I am by no means a ffmpeg guru, I figured out what I do know by Google University and asking questions, so please be kind and forgive me if I ask follow-up questions that may seem n00b-ish, and please provide example commands (preferably in the context of my command below so that I can have a known point of reference to start with).

  



  I have a movie with 4K (HEVC Main 10 HDR) video and DTS-HD MA 7.1 audio that I am looking to leave the video and audio untouched, but to add a 2nd audio track in either EAC3 or if necessary, just AC3 in stereo

  



  So what I am looking for is as follows :

  



  video.mkv

  



  

  • Existing->4k video file (no change)

  


  • Existing->7.1 audio (no change)

  


  • Convert and add->stereo audio as a 2nd audio track to the output.mkv file

  


  



  Below is the command I've historically used with ffmpeg to convert and replace the audio file with the stereo audio, but since I'd prefer to leave the 7.1 audio in place, this doesn't work :
ffmpeg -i "D:\video.mkv" -c:v copy -c:a aac -b:a 128k "D:\output.mkv"

  



  And if this cannot be done as a single command, please also let me know what steps I do need to take to be able to do it.

  



  Thanks in advace,
Mike

  


• Run a piped shell command in background using PHP

  24 décembre 2012, par Jai Dhar

  I'm trying to execute a command in the background using PHP so the web application can continue to load, but having no luck so far.

  The command is for a live streaming application, so involves the following :

  <stream> | ffmpeg <options> | <stream segmenter="segmenter">
  
  </stream></options></stream>

  I can stick the above in a script and execute it fine in the background in bash with &, but this doesn't work in PHP. I also tried using nohup before, and "nohup & echo $ !", but no luck.

  I am also piping all of stderr to /dev/null, and I can verify in apache logs that there is no output generated when I execute the command (but it is executing).

  Some example code below.. what I have after this code doesn't execute until this finishes, which is a long time.

  function streamVid ($mid, $width, $height, $br) {
  
      $cdir = "./temp";
  
      $zmstrm = "zmstreamer -m ".$mid." 2> /dev/null";
  
      $seg = "segmenter - 3 ".$cdir."/sample_".$mid." ".$cdir."/stream_".$mid.".m3u8 ./ 2>/dev/null";
  
      $ffparms = "-f mpegts -analyzeduration 0 -acodec copy -s ".$width."x".$height."   -vcodec libx264 -b ".$br." -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -subq 5 -trellis 1 -refs 1 -coder 0 -me_range 16 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 200k -maxrate ".$br." -bufsize ".$br." -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -level 30 -aspect 320:240 -g 30 -analyzeduration 0 -async 2 - 2> /dev/null";
  
      $url = $zmstrm . " | ffmpeg -t 10 -analyzeduration 0 -i - ". $ffparms . " | " . $seg;
  
      shell_exec("nohup ". $url." & echo $!");       
  
      ob_flush();
  
      flush();
  
  }