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• How to receive the parameters after image cropping using uCrop library ?

  12 décembre 2016, par Dylan

  For cropping an image in my Android app I used the code sample from uCrop library - cropping image library.
  After some searching I didn’t find any library that can Crop Video like the Image cropping. So, I decided to get the first image frame from the video I need to crop and to pass it to uCrop library. After the user will crop this image I want to receive parameters :
  1. Path to the cropped image
  2. Rect params that represents X, Y, width, height
  3. Rotate angle.

  Using this parameters I will be able to crop the video with ffmpeg library (I guess).

  How and where in a code using uCrop library I can receive the params I need after the first frame is cropped ?

• Ffmpeg how do I put image behind video at fixed position [duplicate]

  30 janvier 2020, par andrew cummins

  I have an image (720x1280) I want to use as the canvas. I want to put a video in front of the Image but at a specific section and output to mp4. I attached a screenshot

  I’m familiar with the overlay command but not sure how to get the video overlay in that exact location.

  ffmpeg -loop 1 -i image.png -i video.mp4 -filter_complex "[1:v]scale=400 :-1[fg] ;[0:v][fg]overlay=(W-w)/2 :(H-h)/2:shortest=1" output.mp4

  [Screenshot idea]

  https://i.stack.imgur.com/8dHJ4.jpg

• How to create a fixed image video with ffmpeg that avoids pixelization when it's not maximized ?

  11 août 2022, par Nelson Teixeira

  I have a waiting video in the project I develop. This video is a fixed waiting image with music. I was asked to change the image in the video due to deprecated logo.

  


  So initially I tried just to replace the image in the video using this command :

  


  ffmpeg -i old_waiting_video.mp4 -i new_image.png -filter_complex "[1][0]scale2ref[i][v];[v][i]overlay" -c:a copy new_waiting_video.mp4


  


  This lead to the image became pixelated when the video isn't maximized. When maximized the image is OK. But it looks terrible in the small player.

  


  Here is an image of the problem :

  


  

  


  The above image is the image without zoom out. The left bottom image is a screen capture when I resize it in an image tool and the right bottom is a screen capture of how it looks like in the player.
The image has more than this text, but I thought that wouldn't be appropriate to display my company's logo here. The logo itself is even more pixelized and looks terrible.

  


  So to try to solve this problem I extracted the audio from the file and try to add the image and the audio together to see if it removed the pixelization. So I used this command :

  


  ffmpeg -i audio.m4a -i new_image.png new_waiting_video.mp4


  


  When it failed, searching a bit I came across this other command :

  


  ffmpeg -loop 1 -i new_image.png -i audio.m4a -c:v libx264 -tune stillimage -c:a copy -pix_fmt yuv420p -shortest new_waiting_video.mp4


  


  Again the pixelization ocurred. I know it's possible because this problem doesn't occur in the old logo.

  


  What would be the correct command that allowed that the zoomed out image in the player doesn't pixelate ?

  


  Edit 1

  


  I would also be interested in a command that substitutes the image on the old video as long it doesn't pixelate in the non-maximized player.

  


  Edit 2

  


  

  • Video resolution : 1920x1080

  


  • New image resolution : 1920x1080

  


  • Non-maximized video player size : 640x360

  


  • Video tag : <video src="my-video-url.mp4" style="width: 640px;"></video>