Recherche avancée

Sur d’autres sites (5200)

• (no accepted answer) How to merge 2 overlapping videos into one video using ffmpeg or opencv ?

  3 janvier 2021, par Muhammad Umer

  Merging two videos is easy, been answered couple of times. What I have is multiple overlapping videos. A video might have overlaps with video before it. Meaning if video 1 covers 1-5 timeline then video 2 may overlap 1, and cover 3 to 8. Merging them as is would result in 1-5|3-8, when i need 1-8 only.

  



  Videos are alphabetically sorted.

  



  My general idea of solution is...

  



  

  • grab last frame of the video

  


  • if it's first video continue

  


  • if it's not first video, ie. 2nd, search for frame saved in previous steps frame by frame

  


  • if it reaches to last frame of current video then there is no overlap continue

  


  • if it founds a frame then clip 2nd video up to that frame inclusive and then go to next frame

  


  • once all videos have been analyzed, merge them into one video.

  


  



  I need to translate this to ffmpeg commands. Or opencv if that's a better tool.

  



  If there is better way of doing that, I'm interested in that too.

  


• How does one go about undoing an avformat_seek_file call in libavcodec ?

  2 juillet 2020, par John Allard

  I have an application written around libavcodec that sometimes attempts to seek ahead in a video while performing some work. The call to avformat_seek_file can only seek to a keyframe, so sometimes I end up in a situation where it ends up seek backwards from my current position in the decoding routine causing me to have to repeat work. For example, if I'm on frame 150 and I want to seek to frame 200, but the only key frames in the file are on frames 1 and 100, this call will have me seek back to frame 100, meaning I now have to decode 100 frames to get to 200 instead o 50 frames to get to 200 from my original decoding position of frame 150.

  


  Is there a way for me to tell avformat_seek_file to undo its last seek and reset me to my previous location ? Is there some other way for me to "save" my decoding state to undo this wrongful seek manually ?

  


  edit - it should be noted that my videos are always h264 encoded in an mp4 container.

  


• Video encoding libraries for Windows

  8 février 2012, par John

  ffmpeg is a widely used cross-platform library. But it doesn't support Visual C++, meaning you have to jump through hoops.

  And considering they say the following, it's clear they don't give $0.02 about MSVC users and that makes me uncomfortable for a serious project.. how can one of the most widely used cross-platform libraries not support the most common toolset on the most common OS ?

  There have been efforts to make FFmpeg compatible with MSVC++ in the
  past. However, they have all been rejected as too intrusive,
  especially since MinGW does the job adequately. None of the core
  developers work with MSVC++ and thus this item is low priority. Should
  you find the silver bullet that solves this problem, feel free to
  shoot it at us.

  We strongly recommend you to move over from MSVC++ to MinGW tools.

  It seems unlikely all the Windows developers are doing all this messing about, so are there more Windows-friendly libraries around ?