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• How to bulk insert an audio clip into a batch of videos using ffmpeg

  6 décembre 2018, par Date Captain

  I have a batch of videos, all in MP4 with different lenghts. I would like to insert a specific audio file exactly at the 30 second mark on ALL of the videos.

  For example. if the video file were 1 min & the audio file that i wanted to insert was about 3 seconds long.

  It would go like

  0.0-0.30- Original video with it’s audio
  0.30-0.33- Original video with the Custom audio cue
  0.33-1.00- Original Video with its audio

  ffmpeg -i a.mp4 -itsoffset 00:00:10 -i b.mp3 -map 0:0 -map 1:0 -preset ultrafast o.mp4

  • This does something close to the end result. But
    1. It the entirely mutes the videos audio
    2. Will only work for a single video. Need to batch convert everything in the folder.

• Is it possible to use nvidia hardware to decode videos in opencv ?

  1er janvier 2016, par Mickey Shine

  I am using opencv 3.1 and try to deal with some video files and also streaming videos (rtps ://..). I installed vdpau and compiled ffmpeg 2.8.4 with vdpau enabled. But opencv seems still not using hardware to deocde videos. I don’t use GPU for video output but the integrated graphics.

  [root@localhost ~]# nvidia-smi dmon
  
  # gpu   pwr  temp    sm   mem   enc   dec  mclk  pclk
  
  # Idx     W     C     %     %     %     %   MHz   MHz
  
      0    72    49     0     0     0     0  3505  1001
  
      1    49    47     0     0     0     0  3505  1001
  
      0    73    49     0     0     0     0  3505  1001

  The ’dec’ were always 0. So any advices ?

• Combine many videos in list using FFMPEG

  2 septembre 2022, par anoor1234

  I have a bunch of videos that are MP4s with different FPS, resolution, aspect ratio, basically everything. I'm trying to see if its possible to use FFMPEG to combine them into a single 1080/720 video using a single command, or at least make them all similar format so that combining is easy. Speed and less CPU power would be preferred but I'm in no rush and

  


  I found this command on another stack overflow question :

  


  ffmpeg -i 1.mp4 -i 2.mp4 -i 3.mp4 -filter_complex \
"[0:v]scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:-1:-1,setsar=1,fps=30,format=yuv420p[v0];
 [1:v]scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:-1:-1,setsar=1,fps=30,format=yuv420p[v1];
 [2:v]scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:-1:-1,setsar=1,fps=30,format=yuv420p[v2];
 [v0][0:a][v1][1:a][v2][2:a]concat=n=3:v=1:a=1[v][a]" \
-map "[v]" -map "[a]" -c:v libx264 -c:a aac -movflags +faststart output.mp4


  


  The problem is that I have more that 3 videos to combine and I don't know how to work this command with more, I have an entire list of videos in a list.txt file structured as such :

  


  file './videos/video1.mp4'
file './videos/video2.mp4'
file './videos/video3.mp4'


  


  The code that somewhat worked for me was this

  


  ffmpeg -safe 0 -f concat -i list.txt -c copy output.mp4


  


  It combines the video well and fairly fast but I get weird glitches with the audio and the resolution is weird (I'm hoping for 1920x1080). I suspect this is due to the varying attributes of each video but I'm not sure. I'm familiar with Python but I have found no Python script that can do what I ask. If there any way to combine my list into one video (using FFMPEG or not) reliably ?