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• ffmpeg not finding audio streams ?

  24 septembre 2013, par Jim Miller

  I'm doing some video conversion with ffmpeg v. N-54271-g7f866c1 (a fresh pull from the git sources in late June 2013) on Fedora 19. One of the things I want to do is to concatenate two videos and then convert the result to an mp4. The following code is working well for me :

  ffmpeg -i video_a.mov -i video_b.mov -acodec libfaac -vcodec libx264 
  
       -preset fast -crf 22  -s 940x528 -pix_fmt yuv420p 
  
       -filter_complex '[0:1] [0:0] [1:1] [1:0]  concat=n=2:v=1:a=1 [v] [a]' 
  
       -map '[v]' -map '[a]' output.mp4

  except for a couple of older hunks of test video I've been using. On those, ffmpeg isn't finding the audio stream, and so the above call dies with ffmpeg complaining that Stream specifier ':1' in filtergraph description [0:1][0:0][1:1][1:0] concat=n=2:v=1:a=1 [v] [a] matches no streams. The catch, of course, is that there is an audio stream in the video ; it's just not getting found.

  When ffmpeg starts, I get a description of the input like so :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/priv/videorising7/raw_take_video/v2261-MTQxMzgwMDM4NzAx.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537199360
  
      compatible_brands: qt  
  
      creation_time   : 2011-10-13 16:08:18
  
    Duration: 00:00:25.52, start: 0.000000, bitrate: 49 kb/s
  
      Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 608x342, 47 kb/s, 10.03 fps, 10 tbr, 1k tbn, 2k tbc
  
      Metadata:
  
        creation_time   : 2011-10-13 16:08:18
  
        handler_name    : Apple Alias Data Handler

  I suppose the video might just be so old (2006 ?) that I should be lucky that it plays at all. However, I'm able to run these videos through some other ffmpeg jobs (converting from .mov to .mp4, for instance), but those don't require explicitly referencing the audio and video tracks. Any insights out there ?

• Cut and assemble audio clips

  16 août 2022, par Kruglianin

  Can you tell me if it's possible to make a script for my task ?

  


  Or tell me the right sequence of steps.

  


  An example of the task :

  


  There is an audio file "example.mp3" with duration of 60 seconds.

  


  I want to implement the following sequence of actions.

  


  Cut the first audio fragment from "example.mp3" from second 5 to 15 and cut the second audio fragment from second 50 to 60.

  


  Then, these two audio segments should be merged into one audio file and saved in a new folder named "example.mp3".

  


  That is, the resulting new "example.mp3" would be 20 seconds long and would consist of a first and second audio fragment.

  


• HTML5 : _resetProperties() when setting Audio().src, fix sound1.play() -> sound2.play() -> sound1.play() case on iOS 4.1 not correctly re-assigning original sound URL (related to global audio object.)

  29 janvier 2011, par Scott Schiller

  m script/soundmanager2-jsmin.js m script/soundmanager2-nodebug-jsmin.js m script/soundmanager2-nodebug.js m script/soundmanager2.js HTML5 : _resetProperties() when setting Audio().src, fix sound1.play() -> sound2.play() -> sound1.play() case on iOS 4.1 not correctly re-assigning original sound (...)