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• Concatenate multiple videos with a black screen interval into one video

  21 mars 2016, par AHC

  I am using ffmpeg to join a bunch of videos together.
  I am using the classic join ffmpeg code :
  

  ffmpeg -f concat -i joinlist.txt -c copy joinedfile.mp4

  but the problem is that the videos are of different formats, encodings, but the same size : all 640x480. I want to join them all and put a black screen video with no sound every other video :

  video1 + black_screen_video + video2 + black_screen_video + video3 ...

  I generated a black screen video of 2 seconds duration using :

  ffmpeg -f lavfi -i color=c=black:s=640x480:d=2 black_screen_video.mp4

  so all of the videos are of the same size : 640x480, and 25 fps but different codecs. The videos have sound, except for the black screen video.
  I can’t do anything manual, because the number of videos are around several hundred. So it has got to be an automatic way to do all this.

  When I joined them together using the above code, the resulting video does not play correctly at all.

  I know that I have to re-encode them, but how to do this to all these videos at once, with one line of code ?

  Update :
  I am already using with success this code to join them together, but only three, if I have more than one hundred, it is time consuming to write down one by one :

  ffmpeg -i vid1.avi -i vid2.avi -i vid3.avi -filter_complex "[0:v:0] [0:a:0] [1:v:0] [1:a:0] [2:v:0] [2:a:0] concat=n=3:v=1:a=1 [v] [a]" -map "[v]" -map "[a]" output.mp4

  but this is joining only the videos, not looping the black screen video. When I do with black screen, ffmpeg gives me stream matching errors.

• How to concatenate multiple M4P videos with FFMPEG without audio sync issues ?

  16 mars 2016, par sb3k

  I have been trying to concatenate a number of MP4 clips (h264,aac) using the FFMPEG concat protocol documented here. The clips concatenate successfully, however there are multiple errors in the logs including :

  • Non-monotonous DTS in output stream
  • Past duration too large

  Additionally, it seems that the audio and video go slightly out of sync as more clips are added - though it is more noticeable on certain players (Quicktime & Chrome HTML5).

  Here is the code I am using, any tips would be appreciated !

  Convert each video to temp file

  ffmpeg -y -i <input file="file" /> -vcodec libx264 -acodec aac -f mpegts -bsf:v h264_mp4toannexb -mpegts_copyts 1 <temp file="file"></temp>

  Concat temp files

  ffmpeg -i concat  -map 0 -vcodec copy -aprofile aac_low -acodec aac -strict experimental -cutoff 15000 -vbsf aac_adtstoasc -b:a 32k <output file="file"></output>

• avformat/mxfdec : do not log warning of multiple ANC packets if count is 0

  4 août 2022, par Gavin Smith

  avformat/mxfdec : do not log warning of multiple ANC packets if count is 0
  Some NLVEs may insert a KLV packet for EIA-608 data even though
  
  the number of encapsulated ANC packets is zero.
  

  • [DH] libavformat/mxfdec.c