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Python - Reading a large audio file to a stream?

The Question
I want to load an audio file of any type (mp3, m4a, flac, etc) and write it to an output stream.
I tried using pydub, but it loads the entire file at once which takes forever and runs out of memory easily.
I also tried using python-vlc, but it's been unreliable and too much of a black box.
So, how can I open large audio files chunk-by-chunk for streaming?
Edit #1
I found half of a solution here, but I'll need to do more research for the other half.
TL;DR: Use subprocess and ffmpeg to convert the file to wav data, and pipe that data into np.frombuffer. The problem is, the subprocess still has to finish before frombuffer is used.
...unless it's possible to have the pipe written to on 1 thread while np reads it from another thread, which I haven't tested yet. For now, this problem is not solved.

I think the python package https://github.com/irmen/pyminiaudio can be of helpful. You can stream an audio file like this
import miniaudio
audio_path = "my_audio_file.mp3"
target_sampling_rate = 44100 #the input audio will be resampled a this sampling rate
n_channels = 1 #either 1 or 2
waveform_duration = 30 #in seconds
offset = 15 #this means that we read only in the interval [15s, duration of file]
waveform_generator = miniaudio.stream_file(
filename = audio_path,
sample_rate = target_sampling_rate,
seek_frame = int(offset * target_sampling_rate),
frames_to_read = int(waveform_duration * target_sampling_rate),
output_format = miniaudio.SampleFormat.FLOAT32,
nchannels = n_channels)
for waveform in waveform_generator:
#do something with the waveform....
I know for sure that this works on mp3, ogg, wav, flac but for some reason it does not on mp4/acc and I am actually looking for a way to read mp4/acc

Extract delay between each GIF frame in Python

I am developing a program in Python which creates a video from an HTML file.
The HTML file may contain one animated GIF, and I need to keep the animation in the final video.
I already managed to extract each frame from the GIF, inspired by the method provided in the following GitHub Gist:
https://gist.github.com/revolunet/848913
import os
from PIL import Image
def extractFrames(inGif, outFolder):
frame = Image.open(inGif)
nframes = 0
while frame:
frame.save( '%s/%s-%s.gif' % (outFolder, os.path.basename(inGif), nframes ) , 'GIF')
nframes += 1
try:
frame.seek( nframes )
except EOFError:
break;
return True
extractFrames('ban_ccccccccccc.gif', 'output')
I replaced the GIF source in the HTML with each of these frames, and generated all the frames of the final video using PhantomJS.
Now, I need to get the duration of each frame in the source GIF file, in order to reproduce it in the corresponding frame of the video.
I found no way to achieve this in Python.

How to convert video into millisecond frames instead of converted from basic framerate using OpenCV

Hi I am currently trying to convertvideos into millisecond frames using opencv python. The things is, right now I know how to convert the video based on it's frame rates, instead of millisecond. I don't know how to tweak the code in order to convert the video into series of image from milliseconds rate.
I found my code on this stackoverflow:
import cv2
import numpy as np
import os
vidcap = cv2.VideoCapture('S001-100.avi')
count = 0
success = True
while success:
vidcap.set(cv2.CAP_PROP_POS_MSEC,(count*1000))
success,image=vidcap.read()
last = cv2.imread("frame{}.png".format(count-1))
if np.array_equal(image,last):
break
if not os.path.exists('imgvid'):
os.makedirs('imgvid')
cv2.imwrite("imgvid/frame%d.png" % count,image)
print('{}.sec reading a new frame: {}'.format(count,success))
count +=1
the reason I want to convert into millisecond is because I am trying to make facial expression pattern below than 1 seconds. hopefully there will be an answer for this.

MoviePy: Concatenating video clips causes weird glitches in final video

Is there a way to successfully always patch up any clips together in such a way that prevents weird glitches? I put together a .mp4 from smaller .mp4 files and I got a final video with weird glitches. I am running Python 3.6.1 on Windows 10 through Sublime Text 3. I used MoviePy to do the concatenation.
The code:
from moviepy.editor import VideoFileClip, concatenate_videoclips
import os.path
path = "C:/Users/blah/videos/out/"
cliparray = []
for filename in os.listdir(path):
cliparray.append(VideoFileClip(path + filename))
final_clip = concatenate_videoclips(cliparray)
final_clip.write_videofile(path + "concatenatedvideo.mp4", codec = "libx264")
The weird glitches:
One of the clips turns into a 3x3 grid of smaller clips.
Another has the audio not lined up with the video
Another is sped up faster than what was normal.

I had also glitch while concatenating different video clips. Some had different resolutions and that was making output video file with some sort of glitches. I fixed it with
final_clip = concatenate_videoclips(cliparray, method='compose')
Resulting output was without any glitch, but since they have different resolutions, the moviepy assigns highest resolution among video clips. To fix this you might just crop to same size.

from moviepy.editor import *
#load video 1 in to variable
video_1 = VideoFileClip('video1.mp4')
#load video 2 in to variable
video_2 = VideoFileClip('video2.mp4')
clips = [video_1, video_2]
# concatenating both the clips
final = concatenate_videoclips(clips,method='compose')
#writing the video into a file / saving the combined video
final.write_videofile("merged.mp4")

how to adjust the volume of the audio file by serially getting the voltage signals from the potentiometer using arduino board and python scripts

I want to adjust the volume of the mp3 file while it is being playing by adjusting the potentiometer. I am reading the potentiometer signal serially via Arduino board with python scripts. With the help of pydub library i can able to read the file but cannot adjust the volume of the file while it is being playing. This is the code i have done after a long search
I specified only the portion of Pydub part. for your information im using vlc media player for changing the volume.
>>> from pydub import AudioSegment
>>> song = AudioSegment.from_wav("C:\Users\RAJU\Desktop\En_Iniya_Ponnilave.wav")
While the file is playing, i cannot adjust the value. Please, someone explain how to do it.

First you need decode your audio signal to raw audio and Split your signal in X frames, and you can manipulate your áudio and at every frame you can change Volume or change the Pitch or change the Speed, etc!
To change the volume you just need multiply your raw audio vector by one factor (this can be your potentiometer data signal).
This factor can be different if your vector are in short int or float point format !
One way to get raw audio data from wav files in python is using wave lib
import wave
spf = wave.open('wavfile.wav','r')
#Extract Raw Audio from Wav File
signal = spf.readframes(-1)
decoded = numpy.fromstring(signal, 'Float32');
Now you can multiply the vector decoded by one factor, for example if you want increase 10dB you need calculate 10^(DbValue/20) then in python 10**(10/20) = 3.1623
newsignal = decoded * 3.1623;
Now you need encode the vector again to play the new framed audio, you can use "from struct import pack" and pyaudio to do it!
stream = pyaud.open(
format = pyaudio.paFloat32,
channels = 1,
rate = 44100,
output = True,
input = True)
EncodeAgain = pack("%df"%(len(newsignal)), *list(newsignal))
And finally Play your framed audio, note that you will do it at every frame and play it in one loop, this process is too fast and the latency can be imperceptibly !
stream.write(EncodeAgain)
PS: This example is for float point format !

Ederwander,As u said I have treid coding but when packing the data, im getting total zero. so it is not streaming. I understand the problem may occur in converting the format data types.This is the code i have written. Please look at it and say the suggestion
import sys
import serial
import time
import os
from pydub import AudioSegment
import wave
from struct import pack
import numpy
import pyaudio
CHUNK = 1024
wf = wave.open('C:\Users\RAJU\Desktop\En_Iniya_Ponnilave.wav', 'rb')
# instantiate PyAudio (1)
p = pyaudio.PyAudio()
# open stream (2)
stream = p.open(format = p.get_format_from_width(wf.getsampwidth()),channels = wf.getnchannels(),rate = wf.getframerate(),output = True)
# read data
data_read = wf.readframes(CHUNK)
decoded = numpy.fromstring(data_read, 'int32', sep = '');
data = decoded*3.123
while(1):
EncodeAgain = struct.pack(h,data)
stream.write(EncodeAgain)