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()

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.

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

Are there any advantages of using pyaudio over just that? Ffplay sure seems easier, but I'm not sure if it is the better solution