Play an audio file using FFMPEG, PortAudio, and Python

ffmpeg-pyaudio.py

# FFMPEG example of Blocking Mode Audio I/O https://people.csail.mit.edu/hubert/pyaudio/docs/

"""PyAudio Example: Play a wave file."""

import pyaudio
import wave
import sys
import subprocess

CHUNK = 1024

if len(sys.argv) < 2:
    print("Plays an audio file.\n\nUsage: %s filename.wav" % sys.argv[0])
    sys.exit(-1)

song = subprocess.Popen(["ffmpeg.exe", "-i", sys.argv[1], "-loglevel", "panic", "-vn", "-f", "s16le", "pipe:1"],
                        stdout=subprocess.PIPE)

# instantiate PyAudio (1)
p = pyaudio.PyAudio()

# open stream (2)
stream = p.open(format=pyaudio.paInt16,
                channels=2,         # use ffprobe to get this from the file beforehand
                rate=44100,         # use ffprobe to get this from the file beforehand
                output=True)

# read data
data = song.stdout.read(CHUNK)

# play stream (3)
while len(data) > 0:
    stream.write(data)
    data = song.stdout.read(CHUNK)

# stop stream (4)
stream.stop_stream()
stream.close()

# close PyAudio (5)
p.terminate()

Surprised no one has made an example of this. I also attempted to get the asynchronous demo going but that didn't end well. Maybe some other day.

If you have an ffmpeg binary and pyaudio (PortAudio) installed, you can play this on Windows, Mac, and Linux. Nifty!

Any special point in using ffmpeg to read the audio file as a spawned process, rather than using something like the imported wave for that?

The wave library is only able to read .wav files. By using ffmpeg, you can decode and play as many audio types as it can.

Hello,
I want to do the exact opposite, process audio in PyAudio and write to an ffmpeg stream. Is that possible?

I think you should be able to just feed it through stdin, you'll need to specify the incoming codec type with the -f flag before your -i flag, and your -i flag should be -i pipe: to tell FFmpeg to read from stdin. Here's a general stackoverflow article on that https://stackoverflow.com/questions/45899585/pipe-input-in-to-ffmpeg-stdin I think PyAudio will probably output a raw PCM stream but I don't know exactly what kind, s16le might be a good first try

This should work on windows not tested on Unix yet.

channels=2
audiofps=44100
chunk=1024*2
sample_format=pyaudio.paInt16
audio=pyaudio.PyAudio()
stream = audio.open(format=sample_format,
            channels=channels,
            rate=audiofps,
            frames_per_buffer=chunk,
            input=True)
def audiorun():
    recordcommand=[ffmpeg,
       
        '-f', 's16le',
        '-c:a' ,'pcm_s16le',
        "-ac",str(channels),
  
        "-i","pipe:0",
        '-vn',
     
        #"","",
        # 'b:a',"22k",
        # '-strict','2',
        # "-ac",str(channels),
        "-sample_size",str(chunk),
        "-sample_rate","44100",
        # '-ar','44100',
        # '-c:a' ,'pcm_s16le',
        # '-f','s16le',
        # '-acodec','acc',
        #"pipe:1"]
        #"pipe:1",
        "-acodec","libmp3lame",
        "-f","mp3",
        "game.mp3"
        ]
    B=time.time()
    try:
     
        proc=sp.Popen(recordcommand,stderr=sp.PIPE,stdin=sp.PIPE,stdout=sp.PIPE)
    except Exception as E:
            print("Error",proc.stderr.read())
            raise E

    while True:
        try:
            proc.stdin.write(stream.read(chunk))
        except:
            break
  
        print("Audio running")
        if int(time.time()-B)==20:
            print("Breaking")
            break 
    cap.release()
    proc.stdin.close()
    proc.stderr.close()
    `proc.stdout.close()```

I found using a simple one-liner os.popen call to ffplay which is bundled with ffmpeg works well.