如何接收"icecast"消息?互联网广播流，可以立即使用Python播放? [英] How to receive "icecast" internet radio stream for immediate playback with Python?
问题描述
我想获取Internet音频/广播流(特别是 Longplayer ，单击以获取直接流URL)并使用python播放.
I'm wanting to take an internet audio/radio stream (specifically Longplayer, click for direct stream URL) and play it with python.
最好是后台运行，以便脚本能够继续运行其主循环.(例如，作为游戏背景音乐之类的东西，尽管Pyglet，PyGame等可能会为此提供自己的工具.)
It's preferable that it's backgrounded, such that the script able to continue running its main loop. (e.g. as game background music or something, though Pyglet, PyGame et al. may provide their own tools for that.)
我已经看到一些使用 requests 并将其转储到文件中的录制网络广播的可能过时的示例，但这并不是我想要的，答案的评论似乎有关于 requests 的问题，还有其他争论吗?(请参见此处)
I've seen some likely out of date examples of recording internet radio using requests and dumping it into a file but this isn't exactly what I want and the answers' comments seemed to have arguments about requests being problematic among other things? (see here)
我愿意使用任何可以 pip 的软件包，只要它与Python 3.X兼容即可.(当前使用3.6纯粹是因为我还没有花大力气安装3.7)
I'm open to using any packages you can pip so long as it works with Python 3.X. (Currently using 3.6 purely because I haven't gathered the effort to install 3.7 yet)
重申一下，我不想保存该流，只需将其立即播放(或在需要时进行缓冲?)返回给用户即可.最好是在不阻止脚本的情况下进行脚本，我想这需要多线程/多处理，但这仅是获得播放的第二要领.)
To reiterate, I don't want to save the stream, just play it immediately (or with buffering if that's needed?) back to the user. This is preferably without blocking the script, which I imagine would need multithreadng/multiprocessing but this is secondary to just getting playback.)
推荐答案
对于这些看似简单的问题，似乎总是如此，但细节在于魔鬼.我最终写了一些代码来解决这个问题.可以使用 python3 -m pip install ffmpeg-python PyOpenAL 安装pip依赖项.代码的工作流程可以分为两个步骤:
As it always seems to be the case with these kinds of apparently simple questions, the devil is in the details. I ended up writing some code that should solve this question. The pip dependencies can be installed using python3 -m pip install ffmpeg-python PyOpenAL. The workflow of the code can be divided into two steps:
- 该代码必须从在线流中下载mp3文件数据的二进制块并将其转换为原始PCM数据(基本带符号的uint16_t振幅值)以进行播放.这是通过 ffmpeg-python库完成的，该库是 FFmpeg .该包装器在单独的进程中运行FFmpeg，因此此处不会发生阻塞.
- 然后，代码必须将这些块排队播放.这是通过 PyOpenAL 完成的，它是
- The code must download binary chunks of mp3 file data from an online stream and convert them to raw PCM data (basically signed uint16_t amplitude values) for playback. This is done using the ffmpeg-python library, which is a wrapper for FFmpeg. This wrapper runs FFmpeg in a separate process, so no blocking occurs here.
- The code must then queue these chunks for playback. This is done using PyOpenAL, which is a wrapper for OpenAL. After creating a device and context to enable audio playback, a 3d-positioned source is created. This source is continuously queued with buffers (simulating a "ring buffer") that are filled with data piped in from FFmpeg. This runs on a separate thread from the first step, making downloading new audio chunks run independently from audio chunk playback.
这是该代码的样子(带有一些注释).如果您对代码或此答案的任何其他部分有任何疑问，请告诉我.
Here is what that code looks like (with some commenting). Please let me know if you have any questions about the code or any other part of this answer.
import ctypes
import ffmpeg
import numpy as np
from openal.al import *
from openal.alc import *
from queue import Queue, Empty
from threading import Thread
import time
from urllib.request import urlopen
def init_audio():
#Create an OpenAL device and context.
device_name = alcGetString(None, ALC_DEFAULT_DEVICE_SPECIFIER)
device = alcOpenDevice(device_name)
context = alcCreateContext(device, None)
alcMakeContextCurrent(context)
return (device, context)
def create_audio_source():
#Create an OpenAL source.
source = ctypes.c_uint()
alGenSources(1, ctypes.pointer(source))
return source
def create_audio_buffers(num_buffers):
#Create a ctypes array of OpenAL buffers.
buffers = (ctypes.c_uint * num_buffers)()
buffers_ptr = ctypes.cast(
ctypes.pointer(buffers),
ctypes.POINTER(ctypes.c_uint),
)
alGenBuffers(num_buffers, buffers_ptr)
return buffers_ptr
def fill_audio_buffer(buffer_id, chunk):
#Fill an OpenAL buffer with a chunk of PCM data.
alBufferData(buffer_id, AL_FORMAT_STEREO16, chunk, len(chunk), 44100)
def get_audio_chunk(process, chunk_size):
#Fetch a chunk of PCM data from the FFMPEG process.
return process.stdout.read(chunk_size)
def play_audio(process):
#Queues up PCM chunks for playing through OpenAL
num_buffers = 4
chunk_size = 8192
device, context = init_audio()
source = create_audio_source()
buffers = create_audio_buffers(num_buffers)
#Initialize the OpenAL buffers with some chunks
for i in range(num_buffers):
buffer_id = ctypes.c_uint(buffers[i])
chunk = get_audio_chunk(process, chunk_size)
fill_audio_buffer(buffer_id, chunk)
#Queue the OpenAL buffers into the OpenAL source and start playing sound!
alSourceQueueBuffers(source, num_buffers, buffers)
alSourcePlay(source)
num_used_buffers = ctypes.pointer(ctypes.c_int())
while True:
#Check if any buffers are used up/processed and refill them with data.
alGetSourcei(source, AL_BUFFERS_PROCESSED, num_used_buffers)
if num_used_buffers.contents.value != 0:
used_buffer_id = ctypes.c_uint()
used_buffer_ptr = ctypes.pointer(used_buffer_id)
alSourceUnqueueBuffers(source, 1, used_buffer_ptr)
chunk = get_audio_chunk(process, chunk_size)
fill_audio_buffer(used_buffer_id, chunk)
alSourceQueueBuffers(source, 1, used_buffer_ptr)
if __name__ == "__main__":
url = "http://icecast.spc.org:8000/longplayer"
#Run FFMPEG in a separate process using subprocess, so it is non-blocking
process = (
ffmpeg
.input(url)
.output("pipe:", format='s16le', acodec='pcm_s16le', ac=2, ar=44100, loglevel="quiet")
.run_async(pipe_stdout=True)
)
#Run audio playing OpenAL code in a separate thread
thread = Thread(target=play_audio, args=(process,), daemon=True)
thread.start()
#Some example code to show that this is not being blocked by the audio.
start = time.time()
while True:
print(time.time() - start)
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