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• How to stop a sound when certain other sound is inserted in the mix in ffmpeg ?

  3 avril 2022, par Antonio Oliveira

  I'm using a ffmpeg command that takes a set of sounds, mixes them into a single file, separating them by certain time intervals.

  


  Below is how my command is today.

  


  ffmpeg -i 
close_hh.wav    -i \
crash_l.wav     -i \
crash_r.wav     -i \
floor.wav       -i \
kick_l.wav      -i \
kick_r.wav      -i \
open_hh.wav     -i \
ride.wav        -i \
snare.wav       -i \
splash.wav      -i \
tom_1.wav       -i \
tom_2.wav       -i \
  tom_3.wav  -filter_complex  " [6]adelay=0|0[note_0];  [0]adelay=360|360[note_1];  [6]adelay=1260|1260[note_2];  [0]adelay=1537|1537[note_3];  [6]adelay=2494|2494[note_4];  [5]adelay=2767|2767[note_5];  [0]adelay=2969|2969[note_6];  [6]adelay=3673|3673[note_7];  [5]adelay=3924|3924[note_8];  [0]adelay=4132|4132[note_9];  [0][note_0][note_1][note_2][note_3][note_4][note_5][note_6][note_7][note_8][note_9]amix=inputs=11:normalize=0" record.wav


  


  This is the resulting audio that this command generates :

  


  ffmpg record.wav : https://drive.google.com/file/d/1LFV4ImLKLnRCqZRhZ7OqZy4Ecq5fwT3j/view?usp=sharing

  


  The purpose is to generate a drum recording, so I would like to simulate the dynamics of the hi-hat sounds : When the closed hi-hat is played, the open hi-hat will stop playing immediately if it is still sounding. The same behavior does not happen for any of the other sounds.

  


  One point that makes this a little more challenging is that other sounds can also be played between open hi-hat and closed hi-hat strikes, and theoretically the sound interruption behavior should work normally.

  


  Below is a recording demonstrating the expected result. (My app already reproduces the sound result I need internally, so I just made a simple recording with the microphone to illustrate)

  


  mic record.wav https://drive.google.com/file/d/19x19Fd_URQVo-MMCmGEHIC1SjaQbpWrh/view?usp=sharing

  


  Notice that in the first audio (ffmpeg record.wav) the first sound (open hi-hat) continues playing after the second is played.
In the second audio (mic record.wav) the first sound stops immediately after the second sound is played.

  


  How should the ffmpeg command be to get the expected result ?

  


• fftools/ffmpeg : stop using OutputStream.frame_number for streamcopy

  31 mars 2022, par Anton Khirnov

  fftools/ffmpeg : stop using OutputStream.frame_number for streamcopy
  This field is currently used by checks
  
   skipping packets before the first keyframe
  
   skipping packets before start time
  
  to test whether any packets have been output already. But since
  
  frame_number is incremented after the bitstream filters are applied
  
  (which may involve delay), this use is incorrect. The keyframe check
  
  works around this by adding an extra flag, the start-time check does
  
  not.
  Simplify both checks by replacing the seen_kf flag with a flag tracking
  
  whether any packets have been output by do_streamcopy().
  

  • [DH] fftools/ffmpeg.c
  • [DH] fftools/ffmpeg.h

• ffmpeg to increase video exposure by one f-stop

  18 avril 2022, par GBG

  I am trying to increase the exposure of a video by one f-stop using this Linux command line.

  


  ffmpeg -i SouthFork20220417.mp4 -filter: exposure=1.0  lightened.mp4


  


  I get this error :

  


  [AVFilterGraph @ 0x561ba2fca480] No such filter: 'exposure'
Error reinitializing filters!
Failed to inject frame into filter network: Invalid argument
Error while processing the decoded data for stream #0:1
Conversion failed!


  


  Here is a link to the documentation for the filter.

  


  With advice from @kesh I have also tried :

  


  ffmpeg -i SouthFork20220417.mp4 -vf exposure=1.0  lightened.mp4


  


  and

  


  ffmpeg -i SouthFork20220417.mp4 -filter:v exposure=1.0  lightened.mp4


  


  but these commands returned the same error.

  


  I am new to ffmpeg and do not understand why my command line has failed. Any help is appreciated.