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• How to hide/disable ffmpeg erros when using OpenCV (python) ?

  29 septembre 2013, par Mehran

  I'm using OpenCV python to capture a video.
  This is my code

  import cv2
  
  
  
  cap = cv2.VideoCapture("vid.mp4")
  
  while True:
  
      flag, frame =  cap.read()
  
  
  
      if not flag:
  
          cv2.imshow('video', frame)
  
  
  
      if cv2.waitKey(10) == 27:
  
          break

  When a frame is not ready it produces an error like this

  

  or

  Truncating packet of size 2916 to 1536
  
  [h264 @ 0x7ffa4180be00] AVC: nal size 2912
  
  [h264 @ 0x7ffa4180be00] AVC: nal size 2912
  
  [h264 @ 0x7ffa4180be00] no frame!
  
  
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7ffa41803000] stream 0, offset 0x14565: partial file

  I wanted to find a way to hide this error ! I guess that this error is being produced by ffmpeg. Is there any way to hide or disable it ?

  This error is produced when I call cap.read(). And I also tried to wrap it with try ... except ... but it doesn't work because it doesn't throw any exceptions.

• Merge two or more video files of any format using FFmpeg in iPhone

  20 juillet 2012, par Subhash

  Is there any direct command in FFmpeg to merge videos in iPhone. I need to do this programmatically by setting the command line argument to the FFmpeg containing the input movie files to merge and the output file name.

  ---

  I just wanted to merge two .mov movie files using FFmpeg. I was trying to do this in iPhone where I was creating a command line argument containing two video fies to merge as an input parameter and the destination video file as output parameter and then calling main method of FFmpeg. But for merging videos using FFmpeg first we need to convert it to mpg format and then pass the movie files in mpg format in the command line format. This is the only way found to merge the video using FFmpeg as far as I know. Is there anybody out there done this in a different way ?

• Can't use -shortest parameter when using multiple audio streams ffmpeg

  20 février 2024, par scob_

  I want to add a second audio stream to an mp4 video file already containing sound.

  


  The second audio stream is a little longer than the video, but I want the final product to be the same length.

  


  I tried using the -shortest feature but the second audio stream I wanted to add want not audible at all.

  


  I think -shortest only allows for one stream, so what can I do to keep the video the same length and keep both audio streams ?

  


  Here is the full command I used before asking this question :

  


  ffmpeg -i input.mp4 -i input.m4a -map 0:v -map 0:a -shortest output.mp4


  


  Output of ffmpeg -i output.mp4 :

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:32.08, start: 0.000000, bitrate: 1248 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 480x600 [SAR 1:1 DAR 4:5], 1113 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler