我想知道如何在 python-vlc 中编写音频播放回调

如何解决我想知道如何在 python-vlc 中编写音频播放回调

我编写了如下简单的流音频代码。

如果没有注册回调（部分 **），此代码工作正常。

但我想注册一个播放回调来预处理流数据。

如何注册回调函数可以查看python-vlc文档。

但是我不知道如何编写回调函数。

回调函数的第二个参数 samples 是指向要播放的数据的指针。

如何用这个指针在(*)部分写一个回调函数？

任何答复将不胜感激。

import vlc
import re
import requests
import ctypes

url = "http://serpent0.duckdns.org:8088/kbsfm.pls"
res = requests.get(url)
res.raise_for_status()

# retrieve url
p = re.compile("https://.+")
m = p.search(res.text)
url = m.group()

# AudioPlayCb = ctypes.CFUNCTYPE(None,ctypes.c_void_p,ctypes.c_uint,ctypes.c_int64)
@vlc.CallbackDecorators.AudioPlayCb
def play_callback(opaque,samples,count,pts):
    """
    @param data: data pointer as passed to L{libvlc_audio_set_callbacks}() [IN].
    @param samples: pointer to a table of audio samples to play back [IN].
    @param count: number of audio samples to play back.
    @param pts: expected play time stamp (see libvlc_delay()).
    """
    
    # HOW DO I RETURN SOMETHING FROM HERE? (*)
    pass
    
    return buffer

instance = vlc.Instance(["--prefetch-buffer-size=2000 --prefetch-read-size=5000 --network-caching=1000"]) #define VLC instance
media = instance.media_new(url)

player = media.player_new_from_media()
player.audio_set_format("f32l",48000,2)

# PLAYS WELL WITHOUT THIS LINE (**)
player.audio_set_callbacks(play=play_callback,pause=None,resume=None,flush=None,drain=None,opaque=None)

player.play() #Play the media   

c = input()

我写的播放回调函数如下。 我认为应该将传入的 buffer_array 复制到另一个缓冲区以播放样本。

@vlc.CallbackDecorators.AudioPlayCb
def play_callback(data,pts):
    bytes_read = count * 4 * 2
    buffer_array = ctypes.cast(samples,ctypes.POINTER(ctypes.c_char * bytes_read))
    
    # This code is invalid. To do it right,where should buffer_array be copied to? 
    buffer = bytearray(bytes_read)
    buffer[:] = buffer_array.contents