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• Split a video with ffmpeg, without reencoding, at timestamps given in a txt file

  16 février, par Basj

  Let's say we have a video input.mp4, and a file split.csv containing :

  


  start;end;name
00:00:27.132;00:07:42.422;"Part A.mp4"
00:07:48.400;00:17:17.921;"Part B.mp4"


  


  (or I could format the text file in any other format, but the timestamps must be hh:mm:ss.ddd)

  


  How to split the MP4 into different parts with the given start / end timestamps, and the given filename for each part ?

  


  Is it possible directly with ffmpeg, and if not with a Python script ?

  


• Add PNG image overlay to video starting with non-key frame

  8 mai 2020, par RamRick

  Alright, so I'm trying to edit a bunch of short to very long videos.
The goal is to mute a 1 minute part within each video and overlay that small part with a PNG image for the full duration.

  



  Because this all has to be done as fast as possible, I figured it would be the best idea to split every video into 3 parts, then mute and add the overlay to part #2 and put all 3 parts back together.

  



  The first problem I ran into was that part #2 and #3 always started with a 1-2 second freeze in video, while the audio was fine.

  



  I found out that this was caused by me cutting at key frames and ignoring non-key frames at the beginning.

  



  I fixed that by adding the -copyinkf parameter to also copy all non-key frames, like so :

  



  ffmpeg -i "in.mp4" \
-to 0:04:00 -c:v copy -c:a copy -copyinkf "p1.mp4" \
-ss 0:04:00 -to 0:05:00 -c:v copy -c:a copy -copyinkf "p2.mp4" \
-ss 0:05:00 -c:v copy -c:a copy -copyinkf "p3.mp4"


  



  So I went on and proceeded to mute part #2, like so :

  



  ffmpeg -i "p2.mp4" -af "volume=0" -c:v copy -copyinkf "p2_muted.mp4"


  



  All fine until this point, and IF I put the parts back together right now it would also be quick and accurate, like so :

  



  --parts.txt
file 'p1.mp4'
file 'p2_muted.mp4'
file 'p3.mp4'

ffmpeg -f concat -safe 0 -i parts.txt -c copy "out.mp4"


  



  But now comes the problem :

  



  Since I have to re-encode part #2 to overlay the PNG image, I get the 1-2 seconds freeze frame problem at the beginning again and I can't for the life of me figure out the "equivalent" of -copyinkf for re-encoding a video.

  



  Right now I'm overlaying the PNG image like so :

  



  ffmpeg -i "p2_muted.mp4" -i "../banner.png" -filter_complex "[1][0]scale2ref[i][v];[v][i]overlay" -c:a copy "p2_edited.mp4"


  



  So my question is, what would the equivalent to -copyinkf be, or in case there is a better way than mine, what would that be to achieve my task.

  


• Audio Watermark Repeat with blank in between

  4 mars 2019, par Kathan Shah

  I followed answer at ffmpeg : How to repeat an audio "watermark"

  ffmpeg -i beep.mp3 -af apad -t 5 beep.wav
  
  
  
  ffmpeg -i main.mp3 -filter_complex "amovie=beep.wav:loop=0,asetpts=N/SR/TB[beep];
  
                                      [0][beep]amix=duration=shortest,volume=2"   out.mp3

  First Command makes beep.wav lengthy with remaining part void audio

  but second command trims the empty / void part making beep play immediately and not after 5 seconds

  How can i avoid trimming of empty part in second command ?

  Thanks in Advance