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• How to use ffmpeg make video opacity as 50% ?

  8 septembre 2021, par Xiang Chen

  I had a video, I want to make it opacity low to certain percent.
I use the code below
ffmpeg -i 2.mp4 -vf colorlevels=rimin=0.058:gimin=0.058:bimin=0.058 output.mp4

  


  but is not the effect I want, what I want is like :

  


  

  1. video opacity change to 60%

  


  2. the video see to overlay to dark background

  


  


  Here is the pictures to demonstrate the effect I want :

  


  

  


• How to mix 2 audio files into one in ffmpeg-go ?

  18 juin 2024, par princessluna

  Using ffmpeg-go, I am trying to trim and mix (overlay) two audio files together. Currently I have this code :

  


  func AssebmleAudio(music, effect string, userId int) {

    outputFilePath := filepath.Join(utils.GetRoot(), "users", fmt.Sprintf("%d", userId), "audio.mp3")

    musicStream := Trim(ffmpeg_go.Input(music), 60)
    effectStream := Trim(ffmpeg_go.Input(effect), 60)
    Mix(musicStream, effectStream).Output(outputFilePath).Run()

}

// Mixes specified user audio and vinyl audio asset
func Mix(music, effect *ffmpeg_go.Stream) *ffmpeg_go.Stream {
    return ffmpeg_go.Filter(
        []*ffmpeg_go.Stream{
            music,
            effect,
        },
        "amix",
        ffmpeg_go.Args{"inputs=2:duration=longest:dropout_transition=2"},
    )
}


func Trim(music *ffmpeg_go.Stream, duration int) *ffmpeg_go.Stream {
    return music.Trim(ffmpeg_go.KwArgs{"duration": fmt.Sprintf("%d", duration)})
}


  


  However, AssembleAudio while tested yields the following error :

  


  panic: encountered trim with multiple outgoing edges with same upstream label ; a 'split'' filter is probably required

  


  I found solutions for plain ffmpeg, I also found this question, but I have no idea how to do this in go.

  


• Overlay with fade in-out not showing

  3 mai 2018, par Pier Giorgio Misley

  I can actually add an overlay image in the center of a video from a start time A to an end time B.

  Reading here and there I tried to add a fade-in/fade-out effect to my overlayed image but the result is the image not showing at all in my final video.

  This is my "experiment" :

  -i output.mp4 -i 1.png -filter_complex "[1:v]format=rgba,scale=300:300,fade=in:st=0:d=1:alpha=1,fade=out:st=5:d=1[im];[0][im]overlay=(main_w-overlay_w)/2:(main_h - overlay_h) / 2:enable='between(t,0,5)'" -pix_fmt yuv420p -c:a copy output_0.mp4

  If in understood :

  fade=in:st=0:d=1

  Means that the image should appear at 0’’ with a fade-in effect of 1’’ duration

  fade=out:st=5:d=1

  Means that the image should disappear at 5’’ with a fade-out effect of 1’’ duration

  Isn’t it ?

  Second part would be to add a zoom effect of the image when it is fading in, can I combine the fade-in and the zoom effect toghether ?

  I think that something like this should zoom for a duration of 3 seconds my image overlay, can I add it with another "," separating the filter to the overlayed image ?

  zoompan=z='if(lte(zoom,1.0),1.5,max(1.001,zoom-0.0015))':d=3

  Thanks

  edit :

  The video is 10 sec long. I want an image to be shown with fade in-out and zoom in from 0 to 5 and another from 5 to 10 with the same effect

  Step 1 : adding fade in-out

  -i 0_vid.mp4 -loop 1 -t 1 -i 1.png -filter_complex "[1:v]format=rgba,fade=in:st=0:d=1:alpha=1,fade=out:st=4:d=1:alpha=1[im];[0][im]overlay=(main_w-overlay_w)/2:(main_h - overlay_h)/2:shortest=1" -pix_fmt yuv420p -c:a copy output_0.mp4

  With this solution the fade in works, but the fade out is not even taken in consideration.

  If I add the zoom :

  -i 0_vid.mp4 -loop 1 -t 1 -i 1.png -filter_complex "[1:v]format=rgba,zoompan=z='if(lte(zoom,1.0),1.5,max(1.3875,zoom-0.0015))':d=625,fade=in:st=0:d=1:alpha=1,fade=out:st=4:d=1:alpha=1[im];[0][im]overlay=(main_w-overlay_w)/2:(main_h - overlay_h)/2:shortest=1" -pix_fmt yuv420p -c:a copy output_0.mp4

  This way the image is stretched full screen width and the height is cut. But during the 5 sec animation the image is not resized as normal.

  What I’m aiming for is the image to be zoomed in the video but not to be cut/stretched. I would like to have the image to look smaller at the start and bigger at the end. Is it possible ?

  And also, what am I doing wrong with fade out animation