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• Revision 15718 : En mode debug, forcer le Content-Type à HTML, ce que faisait implicitement ...

  29 mai 2010, par esj@… — Log

  En mode debug, forcer le Content-Type à HTML, ce que faisait implicitement les anciennes versions. Et ne pas non plus faire l’echo final.

• FFmpeg - Crossfading inputs with a duration 1s creates an empty output

  27 août 2021, par Sonia Seddiki

  I am trying to crossfade a silent input with a music to delay the moment when the music starts to play.

  


  I built the command using fluent-ffmpeg so I could choose the duration of the silent input through my program. The duration of the crossfade is calculated according to the duration of the 2 inputs, and equals 0 if one of them is too short.

  


  Below is an example of the resulting command :

  


  ffmpeg -f lavfi -i anullsrc=r=44100 -i music.mp3 -y -filter_complex [0]atrim=duration=0.28[atrim_0];[atrim_0][1]acrossfade=d=0:c1=tri:c2=tri[final] -map [final] output.mp3


  


  However, this command creates an empty output file when the duration of the silent input is inferior to 1 second, regardless of which music input is next. Using the same command with a trim duration > 1 second creates a valid output with the silence and the music.

  


  I have tried to look through the FFmpeg debug report but couldn't really see what was wrong.

  


  Below is an excerpt of the debug log report :

  


  Input file #0 (anullsrc=r=44100):
  Input stream #0:0 (audio): 14 packets read (28672 bytes); 14 frames decoded (14336 samples);
  Total: 14 packets (28672 bytes) demuxed
Input file #1 (music.mp3):
  Input stream #1:0 (audio): 504 packets read (210651 bytes); 504 frames decoded (578372 samples);
  Total: 504 packets (210651 bytes) demuxed
Output file #0 (output.mp3):
  Output stream #0:0 (audio): 0 frames encoded (0 samples); 0 packets muxed (0 bytes);
  Total: 0 packets (0 bytes) muxed


  


  Any idea what could cause this ?

  


  PS : I am using FFmpeg 4.4, and the same command with FFmpeg 4.2 lead to a segmentation fault. Don't know if this can be of any help

  


• FFMPEG combining many files and filters at once

  7 août 2018, par Vadim

  I need to make 1 video from 5 different pieces (mp4,mp3,png) :

  [0] input.mp4 (120fps 4 sec)

  1 sequence of .png (2 sec and its looped)

  [2] sound.mp3 (3 minutes, but i only need the same time as input.mp4)

  [3] Title1.mp4 (30fps its sets in begining)

  [4] Title2.mp4 (30 fps its sets in the end)

  ---

  I tried to explain in picture below :
  

  Its too hard for me to understand the filtergraph syntex as i thinks my steps must be like this :

  ---

  1. I need slow Input.mp4 to 30 frames "setpts=PTS*10,fps=30"and " boxblur=luma_radius=2:luma_power=1 boxblur=2:1" ill get outMain.mp4 [outMain]
  2. Then i overlay .png and .mp3 there is i have a problem, maybe "overlay=shorters=1" and "-loop 1"
     ill get outMain2.mp4[outMain2]
  3. And the final ill need to Concat it all in order "[3][outMain2][4]concat=n=3 out output.mp4"

  How to make it in one action and add a -ultrafast preset, speed is important for me ?
  Thanks

  I understood how to use filtegraph a bit :
  But it appears another question in comments with looping overlay after slowing video in one action...

  In first i slow video :

  ffmpeg -i input.mp4  -r 24 -vf "setpts=(10/1)*PTS" -c:v libx264 -preset ultrafast -crf 26 -c:a copy output.mp4

  Then Overlay png and add .mp3 :

  ffmpeg -i input.mp4 -i alpha.png -i dorn.mp3 -filter_complex "[0:v][1:v]overlay" -c:v libx264 -preset ultrafast -crf 26 -c:a copy -y -map 2:a -shortest out.mp4

  Add begin title and final title :

  ffmpeg -i input.mp4 -i preroll.mp4 -filter_complex "[1][0][1]concat=n=3" -preset ultrafast -crf 26 -c:a copy output.mp4

  But it freezes with "Buffer queue overflow, dropping" Will try to resolve problem.
  The key to the freeze was simple. If i want to paste [0] video in the begining and in the end i must specify one more "-i" for example :

  ffmpeg -i 0.mp4 -i 1.mp4 -i 0.mp4 -filter_complex "[0:v:0][0:a:0][1:v:0][1:a:0][2:v:0][2:a:0] concat=n=3:v=1:a=1 [v][a]" -map "[v]" -map "[a]" -c:v libx264 -preset ultrafast -crf 26 output_video.mp4