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• Ffmpeg mixing audio only for n number of videos using offset and altered duraion

  26 août 2022, par Turgut

  I want to mix audio stream of n amount of video files with ffmpeg, with certain parameters such as :

  


  

  • Duration : I want to specify how long each audio is going to play for each output. For example if I specify ffmpeg -i -d:5 first.mp4 -i second.mp4 it should play the audio from first.mp4 for 5 seconds (I don't know if -d:5 is a real tag it's just an example I've made ).

  


  • Starting point : I want to specify when a given file is going start on the output, I probably need to use -itsoffset 5 but I don't know if it's the right one in terms of interacting with other commands, in on itself it works fine. For example : ffmpeg -i -isoffset 5 first.mp -i second.mp4 causes the second.mp4 to start immediately, and first.mp4 to start after 5 seconds.

  


  • Segmentation : This is the tricky one, I want to specify at which point the input's audio should start. It's like the -ss flag but the problem is it's not working together with -itsoffset. For example when I say ffmpeg -i -ss 5 first.mp4 -i second.mp4 both files should start immediately on the output, but first.mp4 should start on it's 5 seconds. So the 5th second of first.mp4 is heard at the 1st second of the output.

  


  


  This is what I'm trying to achieve, my problem is that I don't know how to implement 'duration' and -ss is not working together with -itsoffset.

  


  At the end I should have something similar to this :

  


  ffmpeg -y -d 5 -itsoffset 3.5 -i first.mp4 -d 10 -ss 10 -itsoffset 5.3 -i 3 -vn -copyts -async 1 -filter_complex amix=inputs=2 out.mp


  


  Which should result in an audio that sounds like this : The first 3.5 seconds are empty, no audio is heard. Then first.mp4 is heard from it's beginning for 5 seconds. When the outputs timestamp reaches 5.3, the 10th seconds of second.mp4 is heard (while first.mp4 is still playing, it's supposed to play until 8.5, so I should hear both files at the same time.) for 10 seconds.

  


  I can't find an example of this and some sources are out-of date.

  


• Two variables for ffmpeg ; use for loop ?

  16 juillet 2020, par Zorba

  I would like to silence sequences in a number of audio files with ffmpeg, which requires to give two variables, the starting point and the end point.

  



  It works nice when you add the two variables in a script like so

  



  
echo "which file do you want to silence"
read filename

echo "When does the muted period start in seconds"
read A

echo "When does the muted period end in seconds"
read B

ffmpeg -i $filename -af "volume=enable='between(t,$A,$B)':volume=0" output_silenced.mp3


  



  I have read all the "similar questions" that come up in a search for "use two variables in bash" and similar search terms, but I can't get my head around this.

  



  I put the variables in two files, with new lines for each number, and tried to call the files in a for loop, which did not work. I also tried to call them in a for loop like so

  



  echo "which file do you want to silence"
read filename

for A in 22 33 57; do

for B in 27 45.5 58.5; do

ffmpeg -i $filename -af "volume=enable='between(t,$A,$B)':volume=0" output_silenced.mp3

mv output_silenced.mp3 filename.mp3
done
done


  



  but the output sounds just like the original input audio !

  



  Can anybody help me out with this ? I have to partly silence many files and it already takes forever to figure out all the start and end moments, and it would be great to get through with this a bit easier !

  



  Thanks a lot in advance !

  


• avformat/http: Add options to set the max number of connection retries

  22 avril 2024, par Derek Buitenhuis

  avformat/http: Add options to set the max number of connection retries
  Not every use case benefits from setting retries in terms of the backoff.
  Signed-off-by : Derek Buitenhuis <derek.buitenhuis@gmail.com>
  

  • [DH] libavformat/http.c
  • [DH] libavformat/version.h