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• C# extract frames from part of a video file

  2 juin 2016, par SiriusNik

  Using AForge ffmpeg wrapper you can extract frames from a video using the VideoFileReader class and save it as a bitmap.

  See this for the exemple :
  Extracting frames of a .avi file

  My problem with that is that you cannot specified where to start reading the frames. It always starts from the beginning of the video file.

  But what if i wanted to extract frames that are in the middle of a two hours long video file. Using that class you’d have to parse the whole first hour juste to get to those frames.

  Does anyone know a way to achieve that ?

• How to create a video editing timeline from images in android ?

  24 février 2015, par xsx4u

  I am developing an app that includes simple video editing. I am using JavaCV and ffmpeg to grab frames and images from a video. What I want to do is to draw a video editing timeline like in most video editors (from the images that I grab from a video). E.x take images from start, end and the middle and display a single view containing these images.

  I do not know what would be the most efficient approach to do this. One option would be to create multiple ImageViews and put images there. Maybe another is to create a custom view. Any help appreciated

• ffmpeg generate overlay complex filter for audio with background image

  8 janvier 2016, par user1793606

  I am experimenting with ffmpeg and would like to generate overlay complex filter for audio with background image. The code normally works, except for when adding -filter_complex "[0:a]showwaves=s=1280x720:mode=line,format=yuv420p[v]" -map "[v]" -map 0:a
  it crashes. I found the example code at https://trac.ffmpeg.org/wiki/Waveform Any help is appreciated.

  Command '['c:/ffmpeg/bin\\ffmpeg.exe', '-y', '-loop', '1', '-r', '1', '-i', 'temp\\bg.png', '-i', 'test.mp3', '-filter_complex', '[0:a]showwaves=s=1280x720:mode=line,format=yuv420p[v]', '-map', '[v]', '-map', '0:a', '-c:v', 'libx264', '-preset', 'ultrafast', '-tune', 'stillimage', '-crf', '15', '-pix_fmt', 'yuv420p', '-strict', 'experimental', '-c:a', 'aac', '-b:a', '256k', '-shortest', '-threads', '0', 'done/test.mp4']'

  EDIT 1 :

  I tested this with the new verson : ffmpeg -y -i input.mp3 -i background.png -filter_complex "[0:a]showwaves=s=1280x720:mode=line,format=yuv420p[v]" -map "[v]" -map 0:a -c:v libx264 -c:a copy output.mp4

  It generates an output file, but only the waveform, no background included. My end goal is to generate the waveform over the background.