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• Replace frames in an AVI with Java

  12 juillet 2018, par webuster

  I’m recording some screencasts and my crap recorder (Camtasia) recorded 2000 videos with a brief black flash (2-3 frames) at, or near the beginning of each.

  I’m looking for a way to automate the replacement of the black frames inside each video with FFmpeg, and I can currently detect which frames are black.

  The problem I have is now : How can I replace frame number X with the content of frame number X-1 in an AVI video ? Not looking to shorten the video, but just to replace a frame in-place.

  Here’s what I have so far :

  FFmpegFrameGrabber g = new FFmpegFrameGrabber("res/video.avi");
  
  g.start();
  
  
  
  FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(new FileOutputStream(new File("res/video_out.avi")), g.getImageWidth(), g.getImageHeight(), 2);
  
  
  
  recorder.setFormat("avi");
  
  recorder.setPixelFormat(AV_PIX_FMT_YUV420P);
  
  recorder.setFrameRate(30);
  
  recorder.setVideoCodec(AV_CODEC_ID_H264);
  
  recorder.setVideoQuality(10);
  
  recorder.setSampleFormat(AV_SAMPLE_FMT_FLTP);
  
  recorder.setSampleRate(48000);
  
  recorder.setAudioCodec(AV_CODEC_ID_AAC);
  
  recorder.setAudioQuality(10);
  
  
  
  g.setFrameNumber(1);
  
  recorder.setFrameNumber(2);
  
  recorder.record(g.grab());
  
  
  
  g.close();
  
  recorder.close();
  
  recorder.release();

  And I’m getting a video back with empty frames (not even black), so I might be messing something here.

  Anyone with experience with FFmpeg ?

• How do you replace audio at a given timestamp with ffmpeg ?

  29 août 2022, par Ed George

  I am trying to use the ffmpeg library to take two FLAC files and replace the audio in File A with the audio in File B at a given timestamp.

  



  For example if File B was to be played at 00:02 and was a second long, playing the output it would be (00:00-0:01) File A Audio -> (00:02-0:03) File B Audio -> (00:04-...) File A Audio

  



  To do this, I have tried the following

  



  ffmpeg -y -i original.flac -i replacement.flac -acodec copy -ss 2 -to 3 -write_xing 0 result.flac


  



  But this only produces the original audio between the specified timestamps.

  



  Is there any way to achieve this within ffmpeg ?

  


• avcodec/avpacket : add av_packet_make_refcounted()

  24 mars 2018, par James Almer

  avcodec/avpacket : add av_packet_make_refcounted()
  It works as a drop in replacement for the deprecated av_dup_packet(),
  
  to ensure a packet is reference counted.
  Reviewed-by : Michael Niedermayer <michael@niedermayer.cc>
  
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] doc/APIchanges
  • [DH] libavcodec/avcodec.h
  • [DH] libavcodec/avpacket.c
  • [DH] libavcodec/version.h