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• How to solve file path error while using ffprobe to find length of video file in python ?

  4 février 2018, par Mitchell Faas

  So, I’m trying to find the length of a video file by the methods discussed here : How to get the duration of a video in Python ?, Using ffmpeg to obtain video durations in python. But in doing so I run in to a problem which I haven’t been able to solve : I get

  FileNotFoundError:[WinError 2] The system cannot find the file specified

  after trying a bunch of troubleshooting steps I’ve started running in IPython and in cmd seperately to see where things might break down. Using a stripped down version of this code in IPython gives me

  In [11]: subprocess.Popen([ffmpeg_path+'ffprobe'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
  
  Out[11]: 

  which seems to be fine, as is CMD at this point. So to adding slight complexity :

  In [17]: subprocess.Popen([ffmpeg_path+'ffprobe -i "F:/tst.mp4"'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
  
  ---------------------------------------------------------------------------
  
  FileNotFoundError                         Traceback (most recent call last)
  
   in <module>()
  
  ----> 1 subprocess.Popen([ffmpeg_path+'ffprobe -i "F:/tst.mp4"'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
  
  
  
  C:\Python\Anaconda3\lib\subprocess.py in __init__(self, args, bufsize, executable, stdin, stdout, stderr, preexec_fn, close_fds, shell, cwd, env, universal_newlines, startupinfo, creationflags, restore_signals, start_new_session, pass_fds, encoding, errors)
  
      705                                 c2pread, c2pwrite,
  
      706                                 errread, errwrite,
  
  --> 707                                 restore_signals, start_new_session)
  
      708         except:
  
      709             # Cleanup if the child failed starting.
  
  
  
  C:\Python\Anaconda3\lib\subprocess.py in _execute_child(self, args, executable, preexec_fn, close_fds, pass_fds, cwd, env, startupinfo, creationflags, shell, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite, unused_restore_signals, unused_start_new_session)
  
      988                                          env,
  
      989                                          cwd,
  
  --> 990                                          startupinfo)
  
      991             finally:
  
      992                 # Child is launched. Close the parent's copy of those pipe
  
  
  
  FileNotFoundError: [WinError 2] The system cannot find the file specified
  
  </module>

  This crashes IPython. Running the very same command ffprobe -i "F:/tst.mp4" in CMD works like a charm.

  Here’s what I tried : Changing / to \ and \ , adding and removing quotes around the file path, changing the path to C :\tst.mp4.

  Running the command os.system(ffmpeg_path+'ffprobe -i "F:/tst.mp4") does work.

  What could possibly be going wrong here ?

• Produce an adaptive multi-resolution mpeg-dash file from an input video file

  1er mars 2021, par Tariq Hasan

  I can produce different resolution mpeg-dash videos from running these commands separately and get one .mpd file for each of the resolutions :

  


  ffmpeg -i /path/to/input.mp4 -vf scale=1920:1080 /path/to/output.mpd
ffmpeg -i /path/to/input.mp4 -vf scale=1280:720 /path/to/output.mpd
ffmpeg -i /path/to/input.mp4 -vf scale=720:480 /path/to/output.mpd
ffmpeg -i /path/to/input.mp4 -vf scale=640:360 /path/to/output.mpd


  


  The question is, how do I get a single .mpd file that maps to all these different resolution videos which would be adaptive in resolution when streamed over the network ?

  


• ffmpeg : Make output file duration that of the file with the longest length [closed]

  27 février 2024, par losercantcode

  I'm going crazy trying to figure this out.

  


  Essentially I'm trying to apply sidechain compression using ffmpeg (for the sake of speed and automation). a2.mp3 in this example is the full length track and a1.wav is a short 5 second, spoken-word clip. The code currently applies the sidechain compression well, but the output file is only that of the spoken-word clips length, so 5 seconds. Is it at all possible to make the output match that of a2.mp3's length instead ? Switching around the input order is not something that's possible as it'll apply the compression to the incorrect track.

  


  Essentially, i'm trying to make it so i'm just layering the spoken-word file on top of the audio track without having to pre-pad the file. I'd rather, if it's possible, this just happen with one block of code within the in one program. I'm interested to see if this is at all possible within ffmpeg.

  


  ffmpeg -i a2.mp3 -i a1.wav -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress=threshold=0.000976563:ratio=10:level_sc=0.015625:release=100:attack=10[compr];[compr][mix]amix=duration=longest[aout]" -map "[aout]" output.wav


  


  a1.wav is mon, a2.mp3 is stereo.

  


  Attempted to implement amix=duration=longest to no avail. Research similar problems on the Stack Exchange that gave unrelated answers.