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• 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

• ffmpeg add two subtitle files to the same mp4

  1er février 2016, par Jay Len

  I have two subtitle tracks files : spanish.ass and english.ass. I want to insert them into an mp4. I can do one or the other but not both.

  I am using :

  ffmpeg -i Clean.mp4 -i spanish.ass -c:s mov_text -c:v copy -c:a copy -metadata:s:s:0 language=spa With1CC.mp4

  and then

  ffmpeg -i With1CC.mp4 -i english.ass -c:s mov_text -c:v copy -c:a copy -metadata:s:s:0 language=eng With2CC.mp4

  ...but while the first statement successfully inserts the Spanish subtitles, the second just changes the visual name of the track to read English. The actual English track is not actually inserted as a second track

• React Native and FFMPEG render text differently (Help me)

  6 février 2021, par Douglas Gondim

  I'm creating a video editing app in React Native that allows you to burn subtitles onto any video. I'm facing a problem that the font size on the phone screen doesn't match the font size after the video is rendered.

  


  I can guarantee that the text is being scaled down appropriately on the app side because the video obviously looks smaller on the phone screen than its original size. So the text that I'm placing on top of the video as a preview needs to be scaled down accordingly.

  


  The problem is each different font seems to have a different scale factor when I render the video. So the previewer is ALWAYS off. My solution was to manually scale up/down each font in regards to its approximate width and height factor. But that's a very poor solution.

  


  I assume it has something to do with something called a font.config file that you can set on ffmpeg.

  


  How can I make eg. Arial, 14 in React Native be rendered the same way as Arial, 14 on ffmpeg ? I really need help with that. I don't even know where to look.