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• Is it possible to combine audio and video from ffmpeg-python without writing to files first ?

  22 janvier 2021, par nullUser

  I'm using the ffmpeg-python library.

  


  I have used the example code : https://github.com/kkroening/ffmpeg-python/tree/master/examples to asynchronously read in and process audio and video streams. The processing is custom and not something a built-in ffmpeg command can achieve (imagine something like tensorflow deep dreaming on both the audio and video). I then want to recombine the audio and video streams that I have created. Currently, the only way I can see to do it is to write both streams out to separate files (as is done e.g. in this answer : How to combine The video and audio files in ffmpeg-python), then use ffmpeg to combine them afterwards. This has the major disadvantage that the result cannot be streamed, i.e. the audio and video must be completely done processing before you can start playing the combined audio/video. Is there any way to combine them without going to files as an intermediate step ?

  


  Technically, the fact that the streams were initially read in from ffmpeg is irrelevant. You may as well assume that I'm in the following situation :

  


  def audio_stream():
    for i in range(10):
        yield bytes(44100 * 2 * 4) # one second of audio 44.1k sample rate, 2 channel, s32le format

def video_stream():
    for i in range(10):
        yield bytes(60 * 1080 * 1920 * 3) # one second of video 60 fps 1920x1080 rgb24 format

# how to write both streams of bytes to file without writing each one separately to a file first?


  


  I would like to use ffmpeg.concat, but this requires ffmpeg.inputs, which only accept filenames as inputs. Is there any other way ? Here are the docs : https://kkroening.github.io/ffmpeg-python/.

  


• avdevice/avdevice : Deprecate AVDevice Capabilities API

  24 janvier 2021, par Andreas Rheinhardt

  avdevice/avdevice : Deprecate AVDevice Capabilities API
  It has been added in 6db42a2b6b22e6f1928fafcf3faa67ed78201004,
  
  yet since then none of the necessary create/free_device_capabilities
  
  functions has been implemented, making this API completely useless.
  Because of this one can already simplify
  
  avdevice_capabilities_free/create and can already remove the function
  
  pointers at the next major bump ; given that the documentation explicitly
  
  states that av_device_capabilities is not to be used by a user, it's
  
  options can already be removed (save for the sentinel).
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] doc/APIchanges
  • [DH] libavdevice/avdevice.c
  • [DH] libavdevice/avdevice.h
  • [DH] libavdevice/version.h
  • [DH] libavformat/avformat.h

• How to create a spectrogram image from an audio file in Python just like how FFMPEG does ?

  2 mai 2020, par hamandishe Mk

  My code :

  



  import matplotlib.pyplot as plt
from matplotlib.pyplot import specgram
import librosa
import librosa.display
import numpy as np
import io
from PIL import Image

samples, sample_rate = librosa.load('thabo.wav')
fig = plt.figure(figsize=[4, 4])
ax = fig.add_subplot(111)
ax.axes.get_xaxis().set_visible(False)
ax.axes.get_yaxis().set_visible(False)
ax.set_frame_on(False)
S = librosa.feature.melspectrogram(y=samples, sr=sample_rate)
librosa.display.specshow(librosa.power_to_db(S, ref=np.max))
buf = io.BytesIO()
plt.savefig(buf,  bbox_inches='tight',pad_inches=0)

# plt.close('all')
buf.seek(0)
im = Image.open(buf)
# im = Image.open(buf).convert('L')
im.show()
buf.close()


  



  Spectrogram produced

  



  

  



  Using FFMPEG

  



  ffmpeg -i thabo.wav -lavfi showspectrumpic=s=224x224:mode=separate:legend=disabled spectrogram.png

  



  Spectrogram produced

  



  

  



  Please help, i want a spectrogram that is exactly the same as the one produced by FFMPEG, for use with a speech recognition model exported from google's teachable machine.
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