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• Overlay system time with milliseconds in ffmpeg

  8 septembre 2017, par userDtrm

  I need to overlay the current system time with milliseconds in ffmpeg. The solutions I’ve come here across simply displays the pts or gmtime (doesn’t show milliseconds). Please find below the script that I’m currently using for this. This simply shows the pts time stamp.

  ffmpeg -f v4l2 -input_format yuyv422 -framerate 30 -s 640x480 -i /dev/video0 -filter_complex "drawtext=fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='frame %{n}\\: %{pict_type}\\: pts=%{pts\\:hms}': x=100: y=50: fontsize=24: fontcolor=yellow@0.8: box=1: boxcolor=blue@0.9" -analyzeduration 5 -c:v libx264 -profile:v baseline -trellis 0 -subq 1 -level 32 -preset ultrafast -tune zerolatency -me_method epzs -r 50 -crf 20 -threads 0 -bufsize 1 -coder 0 -b_strategy 0 -bf 0 -sc_threshold 0 -x264-params vbv-maxrate=2000:vbv-bufsize=100:slice-max-size=200:keyint=10:min-keyint=10:partitions=-parti8x8-partp8x8:me=dia:qpmin=10:qpmax=51:qpstep=4:ref=1: -pix_fmt yuv420p -an -f mpegts - | nc -u 131.227.87.152 7001

  Can someone please let me know how to get the current system time with milliseconds into the ffmpeg output ?

  Thanks.

• os.system() returning False for some reason

  22 février 2017, par Kendall Weihe

  I have a rather large program (memory-wise), it’s a neural network with Tensorflow. I’m working with volumetric data. My end goal is to use ffmpeg to create a video through the volume — where each frame is a z-slice. I’ve successfully done this before using the os python library. The code looks like this :

  videoFile = self.slicesPath + "/0.mp4"
  
  sliceFiles = self.slicesPath + "/%04d.jpg"
  
  os.system("ffmpeg -y -framerate 10 -start_number 0 -i " + sliceFiles + " -vcodec mpeg4 " + videoFile)

  When I step through this with pdb and I try to execute the os.system() command I get -1 as if there were some error.

  (Pdb) os.system("ffmpeg -y -framerate 10 -start_number 0 -i " + sliceFiles + " -vcodec mpeg4 " + videoFile)
  
  -1

  So then I printed the two variables...

  (Pdb) sliceFiles
  
  '/home/volcart/UnsupervisedResults/HercFragment/VAE/0/1/%04d.jpg'
  
  (Pdb) videoFile
  
  '/home/volcart/UnsupervisedResults/HercFragment/VAE/0/1/0.mp4'

  Opened up a python console in a new terminal tab, copy and pasted the exact same line of code (with the strings above instead of variable names), and BAM ! it magically works.

  Why is this ? It works in a separate python console, it works in bash, but it doesn’t work inside my program (when it is the exact same thing). My only guess is something to do with memory, but I know for certain I am not out of memory... my machine has 64GB and python has no limits.

  EDIT

  I just tried a subprocess instead and got this :

  (Pdb) subprocess.call("ffmpeg -y -framerate 10 -start_number 0 -i " + sliceFiles + " -vcodec mpeg4 " + videoFile, shell=True)
  
  *** OSError: [Errno 12] Cannot allocate memory

  But how is it unable to allocate memory ? Python doesn’t have memory bounds right ? I have 64GB of memory, and I can execute the ffmpeg command outside the program, so something is bounding my program.

• Python use ffmpeg not running when using os.system

  4 août 2019, par GILO

  I have been trying to convert mp3 audio to wav file using subprocess. I have installed ffmpeg and libav using home-brew. However whenever I run my code.

  import subprocess
  
  
  
  subprocess.call(['ffmpeg', '-i', 'input.mp3',
  
                 'output.wav'])

  I get this error

  FileNotFoundError : [Errno 2] No such file or directory : ’ffmpeg’ : ’ffmpeg’

  1. I have tried to use pydub but always get ffprobe errors
  2. I have tried
     using os.system alternatively

  For reference I am using macOS Mojave, python 3.7

  Edit :

  Instead of using [’ffmpeg’, ’-i’, ’input.mp3’, ’output.wav’]

  Use [’path/to/ffmpeg’, ’-i’, ’input.mp3’, ’output.wav’]

  Ways to find the path to ffmpeg-----------------------

  Unix(Linux, Mac) : find ffmpeg

  Windows : Where ffmpeg