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• ffmpegthumbnailer issue : dyld : Library not loaded : /usr/local/lib/libavutil.52.18.100.dylib

  18 octobre 2013, par scientiffic

  When I try to run ffmpegthumbnailer, I get the following error :

  dyld: Library not loaded: /usr/local/lib/libavutil.52.18.100.dylib
  
    Referenced from: /usr/local/bin/ffmpegthumbnailer
  
    Reason: image not found
  
    Trace/BPT trap: 5

  I installed ffmpeg using the directions here :

  http://ffmpeg.org/trac/ffmpeg/wiki/MacOSXCompilationGuide

  In my /usr/local/lib folder, I have the file "libavutil.a", but not the one specified in the error mesage.

  How can I solve this error ?

  This is what I was using to try to generate a thumbnail :

  ffmpegthumbnailer -i /public/uploads/tmp/1382121359-37490-7826/thumb_Untitled.mov -o /public/uploads/tmp/1382121359-37490-7826/tmpfile.png -c png -q 10 -s 158

• How do i use libavfilter to deinterlace frames in my video player software

  19 juin 2014, par justanothercoder

  I’m using libavformat/libavcodec/libswscale/libavutil/libavfilter (ffmpeg related libraries) to make a video player.

  I’v gotten into issues with interlaced videos, it just pairs them incorrectly... It always draws the previous bottom frame with the current top frame. Which results in things I don’t want. And i’v tried messing about with the variables around this, it just won’t work. (I haven’t found a player which would play the videos I have correctly, no you can’t have them, i’m sorry)

  I managed to find a way around this, by re-encoding the video with the following command :

  ffmpeg -i video.mp4 -filter:v yadif -vcodec mpeg4 out.avi

  Now what i’d need is directions on how to do this with c++ code, inside my video player.

  I haven’t found any tutorials on the matter and the ffmpeg.c source code is just too alien to me.

  A link to a tutorial would be fine, i just haven’t found it..

  Edit :

  Also this example was worth checking out :

  https://github.com/krieger-od/imgs2video/blob/master/imgs2video.c

  It’s by a gentleman named Andrey Utkin

• Input seeking for frame at specified timestamp with Py-AV

  9 décembre 2019, par neonScarecrow

  I have a project already using Py-AV and am trying to replicate a specific ffmpeg command. The goal is to get a frame roughly around the specified timestamp.

  Here’s the ffmpeg commmand :
  https://trac.ffmpeg.org/wiki/Seeking

  ffmpeg -ss 14 -i https://some_url.mp4 -frames:v 1 frame_at_14_seconds.jpg

  Here’s my code :

      #return one frame around 14 seconds into the movie
  
      target_sec = 14 
  
      container = av.open('https://some_url.mp4', 'r')
  
      container.streams.video[0].thread_type = 'AUTO'
  
      video_stream = next(s for s in container.streams if s.type == 'video')
  
      time_base = float(video_stream.time_base)
  
      target_timestamp = int(target_sec / time_base) + video_stream.start_time
  
      video_stream.seek(target_timestamp)
  
      for frame in container.decode(video_stream):
  
          frame.to_image().save('frame_at_14_seconds.jpg')
  
          break

  Additionally, I have found any documentation about this, but does anyone know if either command (ffmpeg/av.open) is downloading the entire file to a tmp file behind the scenes. I’m looking for a less memory-intensive way to read a frame for every second in an up to 60 second video.