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• Matplotlib animation error : Requested MovieWriter (ffmpeg) not available, while ffmpeg is installed

  3 juillet 2020, par Vivien Bonnot

  I'm trying to animate colormapping representations of parametric complex fonctions using Python.
I gradually put some things together, and checked that they worked properly. But I can't get the animation to be saved.

  


  I encountered this error :

  


  Requested MovieWriter (ffmpeg) not available

  


  However, ffmpeg is indeed installed on my system,
on Windows console ffmpeg -version returns all sorts of informations about ffmpeg. Additionnaly, I also installed ffmpeg in Python scripts directory using pip pip install ffmpeg, which was successfull. I also set up ffmepg path in my code : plt.rcParams['animation.ffmpeg_path'] = "C:\FFmpeg\bin\ffmpeg.exe"

  


  I'm runing out of ideas.

  


  Here is my code.
Thank you for reading.

  


  import numpy as np
import math
import matplotlib
import matplotlib.pyplot as plt
import matplotlib.animation as animation
pi=math.pi
plt.rcParams['animation.ffmpeg_path'] = "C:\FFmpeg\bin\ffmpeg.exe"
fig = plt.figure()

def complex_array_to_rgb(X, theme='dark', rmax=None):
  absmax = rmax or np.abs(X).max()
  Y = np.zeros(X.shape + (3,), dtype='float')
  Y[..., 0] = np.angle(X) / (2 * pi) % 1
  if theme == 'light':
    Y[..., 1] = np.clip(np.abs(X) / absmax, 0, 1)
    Y[..., 2] = 1
  elif theme == 'dark':
    Y[..., 1] = 1
    Y[..., 2] = np.clip(np.abs(X) / absmax, 0, 1)
  Y = matplotlib.colors.hsv_to_rgb(Y)
  return Y

# Set up formatting for the movie files
Writer = animation.writers['ffmpeg']
writer = Writer(fps=15, metadata=dict(artist='Me'), bitrate=1800)

fps = 10
nSeconds = 1
snapshots = [ complex_array_to_rgb(np.array([[3*(x + 1j*y)**(2.9+p/300) + 1/(x + 1j*y)**2 for x in np.arange(-1,1,0.05)] for y in np.arange(-1,1,0.05)])) for p in range( nSeconds * fps ) ]

fig = plt.figure( figsize=(3,3) )

Z2=snapshots[0]
im=plt.imshow(Z2, extent=(-1,1,-1,1))

def animate_func(i):
    if i % fps == 0:
        print( '.')

    im.set_array(snapshots[i])
    return [im]
    
anim = animation.FuncAnimation(
                               fig, 
                               animate_func, 
                               frames = nSeconds * fps,
                               interval = 1000 / fps, # in ms
                               )

anim.save('test_anim.mp4', writer=writer)


  


• Problem updating drawtext with file using ffmpeg [duplicate]

  17 novembre 2020, par drmobbins

  I have a shell script that runs to combine a 24/7 AAC audio stream with a 720p HD picture/background and streams that output live to YouTube. This is for an internet radio station. The script works perfectly except for the drawtext option. The drawtext option references a file that is updated every 15 seconds (using Python and Cron) with the correct song metadata (from the radio automation suite) and is supposed to print the contents of the metadata file to the screen. This happens one time when the ffmpeg command is run in the script, but doesn't update after a song change.

  


  I would assume that since the metadata file is changing every 15 seconds on the server that it would update the song details in the output video that could be seen on YouTube...but it doesn't.

  


  #!/bin/bash

#Quality settings
VBR="1500k"
FPS="30"
QUAL="ultrafast"
AUDIO_ENCODER="aac"

#Youtube settings
YOUTUBE_URL=" rtmp://a.rtmp.youtube.com/live2"
YOUTUBE_KEY="xxxx-xxxx-xxxx-xxxx-xxxx"

#Sources
VIDEO_SOURCE="bg720p.jpg"
AUDIO_SOURCE="http://stream.url"

#Metadata settings
TRACK_METADATA=$(cat metadata.txt)

ffmpeg \
 -loop 1 \
 -re \
 -framerate $FPS \
 -i "$VIDEO_SOURCE" \
 -thread_queue_size 512 \
 -i "$AUDIO_SOURCE" \
 -vf "drawtext=fontfile=OpenSans-Light.ttf:text=$TRACK_METADATA:x=10:y=680:fontsize=20:fontcolor=white" \
 -c:v libx264 -tune stillimage -pix_fmt yuv420p -preset $QUAL -r $FPS -g $(($FPS *2)) -b:v $VBR \
 -c:a $AUDIO_ENCODER -threads 6 -ar 44100 -b:a 64k -bufsize 512k -pix_fmt yuv420p \
 -f flv $YOUTUBE_URL/$YOUTUBE_KEY


  


  What am I missing that will make the output continually check for file changes and use drawtext to display the contents. Thanks in advance !

  


• Change file format from flv to anything android will play

  19 octobre 2011, par Bilthon

  I need to take this file which encoded is in h264 but in a flv container and just put it in a mp4, 3gp or whatever file format the android MediaPlayer will understand.

  I want to do this natively. As I will not be decoding nor encoding anything I think I will not be wasting a lot of power (am I wrong ?)

  I followed the instructions from here http://www.roman10.net/?p=394 and could sucessfully compile and use ffmpeg and use it with mp4 and 3gp files.

  But when it comes to flv files it fails. I understand there is no format definition for flv files in that specific port of ffmpeg for android.

  There is no libavformat/flv.h header file for instance.

  Maybe that's why this works :

  extern AVInputFormat ff_mov_demuxer ;
  av_register_input_format(&ff_mov_demuxer) ;

  While this fails :

  extern AVInputFormat ff_flv_demuxer;
  
  av_register_input_format(&ff_flv_demuxer);

  Question is, is there a light at the end of the tunnel ? has someone done something similar ? is it useful ? I mean, I can always just throw the flv media file into a flash player and voila.. the thing is that this would be a parcial solution, as it will not work for all those folks running slower devices that can't yet run Flash.

  Nelson

  PS. Just in case. Here's some info about the file I'm talking about :

  ffmpeg -i rio.flv 
  
  ffmpeg version N-32624-gea8de10, Copyright (c) 2000-2011 the FFmpeg developers
  
    built on Sep 15 2011 23:31:42 with gcc 4.5.2
  
    configuration: --enable-libfaac --enable-libmp3lame --enable-librtmp --enable-libtheora --enable-libx264 --enable-libxvid --enable-gpl --enable-nonfree
  
    libavutil    51. 16. 0 / 51. 16. 0
  
    libavcodec   53. 15. 0 / 53. 15. 0
  
    libavformat  53. 12. 0 / 53. 12. 0
  
    libavdevice  53.  3. 0 / 53.  3. 0
  
    libavfilter   2. 42. 0 /  2. 42. 0
  
    libswscale    2.  1. 0 /  2.  1. 0
  
    libpostproc  51.  2. 0 / 51.  2. 0
  
  
  
  Seems stream 0 codec frame rate differs from container frame rate: 2000.00 (2000/1) -> 14.99 (15000/1001)
  
  Input #0, flv, from 'rio.flv':
  
    Duration: 00:01:00.06, start: 0.000000, bitrate: 783 kb/s
  
      Stream #0.0: Video: h264 (Main), yuv420p, 704x480 [SAR 10:11 DAR 4:3], 14.99 tbr, 1k tbn, 2k tbc