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• Stacking videos with ffmpeg via MATLAB not working as expected

  18 juillet 2022, par ersatzsheep

  I am stacking 4 video inputs in a 2x2 grid and running into a conversion failure.

  


  Basically, at least one of the videos is just a filler black video that I generated with this line (MATLAB, hence the eval) :

  


  eval(['!ffmpeg -framerate 1/3600 -i black_frame.JPG -c:v libx264 -t 3600 -pix_fmt yuv420p -vf scale=320:240 black_frame.mp4']);


  


  The other video inputs are 4 hr long videos with identical specs. I've concatenated them with this line :

  


  eval(['!ffmpeg -i "' v1 '" -i "' v3 '" -i "' v2 '" -i "' v4 '" -filter_complex "  [0:v] setpts=PTS-STARTPTS, scale=qvga [a0]; [1:v] setpts=PTS-STARTPTS, scale=qvga [a1]; [2:v] setpts=PTS-STARTPTS, scale=qvga [a2];  [3:v] setpts=PTS-STARTPTS, scale=qvga [a3];  [a0][a1][a2][a3]xstack=inputs=4:layout=0_0|0_h0|w0_0|w0_h0[out] "  -map "[out]" -c:v libx264 "' output '"'])  


  


  When I input v1-v4 with normal videos (not the filler black video), it outputs very quickly and everything is good. The line to generate the filler black video is very fast too. But when I sub one of the video inputs with the file path for the filler black video, the speed tanks exponentially, stalls, and conversion fails.

  


  Any pointers for me ? I also tried just subbing one of the inputs with a black image file instead of generating a whole video and inputting that. But it does the same thing :/ Does it have to do with frame rate ? Should I try a different approach ? Thanks.

  


• FFMPEG Image overlay Fade in and out on Video not working properly

  24 août 2015, par HardCore CODER

  hi i have a video around 30 second and i want to set overlay image between 5 - 10 second only and play remaining video as per as.

  But i have an issue the video start with black screen and fade in on 5th second and play well upto 10 second and fade out to black after 10 second and whole video is black screen upto 30 second

  -i input.mp4 -i 34232944.png -filter_complex " [0:v][1:v] overlay=0:0:enable=’between(t,5,10)’,fade=t=in:st=5:d=1,
  fade=t=out:st=10:d=1 ’" -c:v libx264 -crf 23 output.mp4

  video link :-
  https://www.dropbox.com/s/vmbed5vxtakfhg5/TinyTake24-08-2015-02-59-59.mp4?dl=0

  Please help me.
  Thanks

• sppedUp FFmpegKit overlay Flutter

  17 septembre 2023, par mlika

  I'm using FFmpegKit to overlay text on video :
I'm coding it for macos app, I double checked the CPU usage,it's using only 20%
I have MAC M1 PRO

  


    String drawtextFilter = 'drawtext=fontfile=\'$_fontPath\':'
          'textfile=\'${segments[i].textFilePath}\':'
          'x=(w-text_w)/2:y=(h-text_h)/2:'
          'fontsize=65:fontcolor=white@0.8:' // @0.8 sets the opacity
          'bordercolor=black:borderw=9:'
          'shadowcolor=black:shadowx=5:shadowy=5:' // Adding shadow
          'box=1:boxcolor=black@0.1:boxborderw=20:' // Adding background box
          'fix_bounds=1:'
          'line_spacing=10:'
          'enable=\'between(t,0,${segments[i].duration})\'';
  String command =
          '-i "${segments[i].videoPath}" -vf "$drawtextFilter" -c:v h264_videotoolbox -threads 0 -y "$outputPath"';



  


  The problem is it's taking too long to finish the speed is around 0.6
Is there a solution or alternative as, I'm converting 1hour+ videos and it's taking too much time.
Thanks

  


  

  • I tried compute and Isolate to run multiple ffmpeg but it still very slow