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• Python extract wav from video file

  31 octobre 2015, par xolodec

  Related :

  How to extract audio from a video file using python ?

  Extract audio from video as wav

  How to rip the audio from a video ?

  My question is how could I extract wav audio track from video file, say video.avi ?
  I read many articles and everywhere people suggest to use (from Python) ffmpeg as a subprocess (because there are no reliable python bindings to ffmpeg - the only hope was PyFFmpeg but i found it is unmaintaned now). I don’t know if it is right solution and i am looking for good one.
  I looked to gstreamer and found it nice but unable to satisfy my needs — the only way I found to accomplish this from command line looks like

   gst-launch-0.10 playbin2 uri=file://`pwd`/ex.mp4  audio-sink='identity single-segment=true ! audioconvert ! audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)16000, channels=(int)1 ! wavenc !  filesink location=foo.wav’ 

  But it is not efficient because i need to wait ages while playing video and simultaneously writing to wav file.

  ffmpeg is much better :

  avconv  -i foo.mp4  -ab 160k -ac 1 -ar 16000 -vn ffaudio.wav

  But i am unable to launch it from python (not as a command line subprocess). Could you please point me out pros and cons of launching ffmpeg from python as a command line utility ? (I mean using python multiprocessing module or something similar).

  And second question.

  What is simple way to cut long wav file into pieces so that i don’t break any words ? i mean pieces of 10-20 sec length with start and end during the pause in sentences/words ?

  i know how to break them on arbitrary pieces :

  import wave
  
  
  
  
  
  win= wave.open('ffaudio.wav', 'rb')
  
  wout= wave.open('ffsegment.wav', 'wb')
  
  
  
  t0, t1= 2418, 2421 # cut audio between 2413, 2422 seconds
  
  s0, s1= int(t0*win.getframerate()), int(t1*win.getframerate())
  
  win.readframes(s0) # discard
  
  frames= win.readframes(s1-s0)
  
  
  
  wout.setparams(win.getparams())
  
  wout.writeframes(frames)
  
  
  
  win.close()
  
  wout.close()

• Using Python script to cut long videos into chunks in FFMPEG

  23 février 2016, par Michael Hamilton

  Starting off by saying I’m not a programmer, but I really need the application this Python script I found says it can do.

  Auto-Splitting Script by Antarctic Nest of Icephoenix

  Basically I have a directory of long .MP4s that need to be cut into equal parts based on a total running time of 3 hours 15 minutes. For example, I would have an 8 hour video that needs to be cut into smaller parts each under 3:15:00.

  We’ve been manually crating FFMPEG codes to do this, but I found the Python script above that seems like it will do what we are needing. The issue is that I have no Python experience. I don’t know where in the script to enter in the folder path with the videos, or where to specify my codecs, or where to tell the program that the max time for each video chunk is 3:15:00.

  I’m on a 64-bit windows system working in command prompt

  Here’s what I have done :

  • Installed python 3
  • downloaded the script
  • I can click on the script to see the cmd window flash to indicate it’s running
  • I enter "C :\Python34\python.exe V :\ffmpeg\ffmpeg-split.py" into cmd

  • output is

    File "V :\ffmpeg\ffmpeg-split.py", line 16
    print "Split length can’t be 0"

      SyntaxError: Missing parentheses in call to 'print'

  I have no idea where to go from here. It seems like the script is loading properly, but I haven’t entered my variables. Any help with where to put the information would be appreciated.

  Here is the FFMPEG code we usually use :

  ffmpeg -i V :\ffmpeg\88518_63c392af.mp4 -vcodec libx264 -acodec copy -vf fps=fps=30000/1001 -ss 00:05:01.000 -t 02:43:49.000 V :\events\88518.mp4

  The ffmpeg codes we use :

  -i is a .mp4

  -vcodec h.264 codec

  -acodec should be “copy” or can be “libvo_aacenc”

  -vf fps=30000/1000 a forced fps of 29.97

  -ss is start time (we would use this to manually cut into parts along with -t)

  -t is duration (we would calculate the duration for each part as the total run time divided by the equal time under 3:15:00 be it two, three, or four parts)

  Thank you a million dollars

• How to use concat-demuxer in ffmpeg-python ?

  21 août 2024, par user12355248

  I want to merge 2 or more videos in short time.

  


  I think that concat-demuxer is best, but it need TXT file.

  


  In python, is it possible to use ffmpeg concat-demuxer without TXT file ?