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• FFMPEG call from PHP

  21 juillet 2014, par Dan Winduss

  I have a command that runs correctly through ffmpeg in windows command prompt.

  ffmpeg -i Wildlife.mp4 -vf "[in]drawtext=fontsize=100:borderw=5:fontcolor=white:fontfile='impact.ttf':text='Foo':x=(w-text_w)/2:y=20, drawtext=fontsize=100:borderw=5:fontcolor=white:fontfile='impact.ttf':text='Bar':x=(w-text_w)/2:y=(h-text_h)-20[out]" -codec:a copy output.mp4 

  But when I call it from php (ajax call), it fails and gives no error.

  <?php
  
  shell_exec("ffmpeg -i Wildlife.mp4 -vf \"[in]drawtext=fontsize=100:borderw=5:fontcolor=white:fontfile='impact.ttf':text='Foo':x=(w-text_w)/2:y=20,drawtext=fontsize=100:borderw=5:fontcolor=white:fontfile='impact.ttf':text='Bar':x=(w-text_w)/2:y=(h-text_h)-20[out]\" -codec:a copy output.mp4");
  
  ?>

• problem with executing flutterFFmpeg command

  28 février 2021, par Sadiq Samaila

  the code below is for creating a robot voice with flutterFFmpeg

  


  so here is the code I ran

  


                        String commandToExecute =
                      "-i $aud -filter_complex 'afftfilt=real='hypot(re,im)*sin(0)':imag='hypot(re,im)*cos(0)':win_size=512:overlap=0.75' " +
                          outputPath;
   
                  _flutterFFmpeg.execute(commandToExecute).then((rc) => print(
                      "FFmpeg process exited with rc $rc $appDocumentDir"));


  


  and I got this error

  


  E/mobile-ffmpeg( 5493): [AVFilterGraph @ 0x7ce619159800] No such filter: 'im)*sin(0):imag'
E/mobile-ffmpeg( 5493): Error initializing complex filters.
E/mobile-ffmpeg( 5493): Invalid argument
D/flutter-ffmpeg( 5493): FFmpeg exited with rc: 1


  


  I tried changing all single quote(') to double quote(") in the command but it did not work.

  


• Inconsistent behavior when placing adjacent video overlays

  24 juillet 2023, par abingham

  This script uses ffmpeg to overlay a red [1] and blue [2] stream atop a yellow [0] stream. The intent is that the red stream will be exactly adjacent to the blue stream ; at frame 1731 the output video should transition immediately from pure red to pure blue :

  


  # These values result in a blank frame where the videos join at around 58s
LENGTH=1800
SPLIT_AT=1731

# These values work just fine.
# LENGTH=1800
# SPLIT_AT=2

ffmpeg \
-f lavfi -r 30 -i "color=c=yellow:s=1920x1080" \
-f lavfi -r 30 -i "color=c=990000:s=1920x1080" \
-f lavfi -r 30 -i "color=c=000099:s=1920x1080" \
-filter_complex \
"[1]concat=n=1[red_concat];"\
"[red_concat]tpad=start=0[red_pad];"\
"[0][red_pad]overlay=enable=between(n\,0\,$SPLIT_AT):eof_action=repeat[red_overlay];"\
"[2]concat=n=1[blue_concat];"\
"[blue_concat]tpad=start=$SPLIT_AT[blue_pad];"\
"[red_overlay][blue_pad]overlay=enable=between(n\,$SPLIT_AT\,$LENGTH):eof_action=repeat[blue_overlay];"\
"[blue_overlay]trim=end_frame=$LENGTH[full];" \
 -map "[full]" video.mp4 -y


  


  However, what I see is that there is a single black frame between the pure red and pure blue. This black seems to be coming from the frames that tpad adds.

  


  What I don't understand is why I'm seeing that black frame. As far as I can tell, my uses of tpad and overlay/enable-between should produce a seamless transition from red to blue. And indeed, if I change the SPLIT_AT value to almost anything else I get exactly that ; the value 1731 is "special" in some way.

  


  Can anyone explain what's going on ? Maybe more importantly, can anyone reproduce this problem ?

  


  My first thought was that I've got some form of fencepost error in how I'm using tpad or enable-between. However, that doesn't explain why the script works for most values but not 1731. This difference in results feels like there's a rounding error somewhere, but since I'm dealing purely in terms of integer frame numbers, I don't see how I could be introducing them.

  


  A few notes :

  


  


  • This is a drastically reduced example from a larger video compositing system. Things like the use of concat may appear unnecessary, but they're representative of what the larger system is doing.

    


  


  • I'm using ffmpeg-6.0 installed via homebrew on an M1 macbook