这个问题的目标是试图找出如何使用pyglet播放流式音频。第一个是确保你能够使用pyglet播放mp3文件，这就是第一个片段的目的：
import sys
import inspect
import requests
import pyglet
from pyglet.media import *
pyglet.lib.load_library('avbin')
pyglet.have_avbin = True
def url_to_filename(url):
return url.split('/')[-1]
def download_file(url, filename=None):
filename = filename or url_to_filename(url)
with open(filename, "wb") as f:
print("Downloading %s" % filename)
response = requests.get(url, stream=True)
total_length = response.headers.get('content-length')
if total_length is None:
f.write(response.content)
else:
dl = 0
total_length = int(total_length)
for data in response.iter_content(chunk_size=4096):
dl += len(data)
f.write(data)
done = int(50 * dl / total_length)
sys.stdout.write("\r[%s%s]" % ('=' * done, ' ' * (50 - done)))
sys.stdout.flush()
url = "https://freemusicarchive.org/file/music/ccCommunity/DASK/Abiogenesis/DASK_-_08_-_Protocell.mp3"
filename = "mcve.mp3"
download_file(url, filename)
music = pyglet.media.load(filename)
music.play()
pyglet.app.run()
如果您已经安装了库pip install pyglet requests并且此时还安装了AVBin，那么您应该能够在下载后收听mp3。
一旦我们达到这一点，我想弄清楚如何玩和使用pyglet +请求以与大多数现有Web视频/音频播放器类似的方式缓冲文件。这意味着播放文件时无需等待文件完全下载。
阅读pyglet媒体docs后，您可以看到这些类可用：
media
sources
base
AudioData
AudioFormat
Source
SourceGroup
SourceInfo
StaticSource
StreamingSource
VideoFormat
player
Player
PlayerGroup
我已经看到有另外类似的SO问题，但它们没有得到妥善解决，其内容也没有提供很多相关细节：
这就是为什么我创建了一个新问题。你如何使用pyglet播放流音频？你能用上面的mcve作为基础提供一个小例子吗？
答案 0 :(得分：6)
假设您不想导入新程序包来为您执行此操作-可以花些功夫。
首先，让我们看一下Pyglet源代码，看看media.load中的media/__init__.py。
"""Load a Source from a file.
All decoders that are registered for the filename extension are tried.
If none succeed, the exception from the first decoder is raised.
You can also specifically pass a decoder to use.
:Parameters:
`filename` : str
Used to guess the media format, and to load the file if `file` is
unspecified.
`file` : file-like object or None
Source of media data in any supported format.
`streaming` : bool
If `False`, a :class:`StaticSource` will be returned; otherwise
(default) a :class:`~pyglet.media.StreamingSource` is created.
`decoder` : MediaDecoder or None
A specific decoder you wish to use, rather than relying on
automatic detection. If specified, no other decoders are tried.
:rtype: StreamingSource or Source
"""
if decoder:
return decoder.decode(file, filename, streaming)
else:
first_exception = None
for decoder in get_decoders(filename):
try:
loaded_source = decoder.decode(file, filename, streaming)
return loaded_source
except MediaDecodeException as e:
if not first_exception or first_exception.exception_priority < e.exception_priority:
first_exception = e
# TODO: Review this:
# The FFmpeg codec attempts to decode anything, so this codepath won't be reached.
if not first_exception:
raise MediaDecodeException('No decoders are available for this media format.')
raise first_exception
add_default_media_codecs()
此处的关键行是loaded_source = decoder.decode(...)。本质上，要加载音频，Pyglet会获取一个文件并将其传输到媒体解码器（例如FFMPEG），然后，该媒体解码器会返回Pyglet可以使用内置Player类播放的“帧”或数据包列表。如果压缩了音频格式（例如mp3或aac），则Pyglet将使用外部库（当前仅支持AVBin）将其转换为原始的解压缩音频。您可能已经知道其中一些。
因此，如果我们想了解如何将字节流填充到Pyglet的音频引擎中而不是文件中，则需要查看其中一个解码器。对于此示例，让我们使用FFMPEG，因为它是最容易访问的。
在media/codecs/ffmpeg.py中：
class FFmpegDecoder(object):
def get_file_extensions(self):
return ['.mp3', '.ogg']
def decode(self, file, filename, streaming):
if streaming:
return FFmpegSource(filename, file)
else:
return StaticSource(FFmpegSource(filename, file))
它继承的“对象”是MediaDecoder中的media/codecs/__init__.py。回到load中的media/__init__.py函数，您将看到pyglet将基于文件扩展名选择MediaDecoder，然后返回其decode函数并将该文件作为参数以获取音频。数据包流的形式。该数据包流是Source对象；每个解码器都有自己的风格，形式为StaticSource或StreamingSource。前者用于将音频存储在内存中，后者用于立即播放。 FFmpeg的解码器仅支持StreamingSource。
我们可以看到FFMPEG是FFmpegSource，也位于media/codecs/ffmpeg.py中。我们找到了这个类的巨人：
class FFmpegSource(StreamingSource):
# Max increase/decrease of original sample size
SAMPLE_CORRECTION_PERCENT_MAX = 10
def __init__(self, filename, file=None):
if file is not None:
raise NotImplementedError('Loading from file stream is not supported')
self._file = ffmpeg_open_filename(asbytes_filename(filename))
if not self._file:
raise FFmpegException('Could not open "{0}"'.format(filename))
self._video_stream = None
self._video_stream_index = None
self._audio_stream = None
self._audio_stream_index = None
self._audio_format = None
self.img_convert_ctx = POINTER(SwsContext)()
self.audio_convert_ctx = POINTER(SwrContext)()
file_info = ffmpeg_file_info(self._file)
self.info = SourceInfo()
self.info.title = file_info.title
self.info.author = file_info.author
self.info.copyright = file_info.copyright
self.info.comment = file_info.comment
self.info.album = file_info.album
self.info.year = file_info.year
self.info.track = file_info.track
self.info.genre = file_info.genre
# Pick the first video and audio streams found, ignore others.
for i in range(file_info.n_streams):
info = ffmpeg_stream_info(self._file, i)
if isinstance(info, StreamVideoInfo) and self._video_stream is None:
stream = ffmpeg_open_stream(self._file, i)
self.video_format = VideoFormat(
width=info.width,
height=info.height)
if info.sample_aspect_num != 0:
self.video_format.sample_aspect = (
float(info.sample_aspect_num) /
info.sample_aspect_den)
self.video_format.frame_rate = (
float(info.frame_rate_num) /
info.frame_rate_den)
self._video_stream = stream
self._video_stream_index = i
elif (isinstance(info, StreamAudioInfo) and
info.sample_bits in (8, 16) and
self._audio_stream is None):
stream = ffmpeg_open_stream(self._file, i)
self.audio_format = AudioFormat(
channels=min(2, info.channels),
sample_size=info.sample_bits,
sample_rate=info.sample_rate)
self._audio_stream = stream
self._audio_stream_index = i
channel_input = avutil.av_get_default_channel_layout(info.channels)
channels_out = min(2, info.channels)
channel_output = avutil.av_get_default_channel_layout(channels_out)
sample_rate = stream.codec_context.contents.sample_rate
sample_format = stream.codec_context.contents.sample_fmt
if sample_format in (AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_U8P):
self.tgt_format = AV_SAMPLE_FMT_U8
elif sample_format in (AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S16P):
self.tgt_format = AV_SAMPLE_FMT_S16
elif sample_format in (AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S32P):
self.tgt_format = AV_SAMPLE_FMT_S32
elif sample_format in (AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_FLTP):
self.tgt_format = AV_SAMPLE_FMT_S16
else:
raise FFmpegException('Audio format not supported.')
self.audio_convert_ctx = swresample.swr_alloc_set_opts(None,
channel_output,
self.tgt_format, sample_rate,
channel_input, sample_format,
sample_rate,
0, None)
if (not self.audio_convert_ctx or
swresample.swr_init(self.audio_convert_ctx) < 0):
swresample.swr_free(self.audio_convert_ctx)
raise FFmpegException('Cannot create sample rate converter.')
self._packet = ffmpeg_init_packet()
self._events = [] # They don't seem to be used!
self.audioq = deque()
# Make queue big enough to accomodate 1.2 sec?
self._max_len_audioq = 50 # Need to figure out a correct amount
if self.audio_format:
# Buffer 1 sec worth of audio
self._audio_buffer = \
(c_uint8 * ffmpeg_get_audio_buffer_size(self.audio_format))()
self.videoq = deque()
self._max_len_videoq = 50 # Need to figure out a correct amount
self.start_time = self._get_start_time()
self._duration = timestamp_from_ffmpeg(file_info.duration)
self._duration -= self.start_time
# Flag to determine if the _fillq method was already scheduled
self._fillq_scheduled = False
self._fillq()
# Don't understand why, but some files show that seeking without
# reading the first few packets results in a seeking where we lose
# many packets at the beginning.
# We only seek back to 0 for media which have a start_time > 0
if self.start_time > 0:
self.seek(0.0)
---
[A few hundred lines more...]
---
def get_next_video_timestamp(self):
if not self.video_format:
return
if self.videoq:
while True:
# We skip video packets which are not video frames
# This happens in mkv files for the first few frames.
video_packet = self.videoq[0]
if video_packet.image == 0:
self._decode_video_packet(video_packet)
if video_packet.image is not None:
break
self._get_video_packet()
ts = video_packet.timestamp
else:
ts = None
if _debug:
print('Next video timestamp is', ts)
return ts
def get_next_video_frame(self, skip_empty_frame=True):
if not self.video_format:
return
while True:
# We skip video packets which are not video frames
# This happens in mkv files for the first few frames.
video_packet = self._get_video_packet()
if video_packet.image == 0:
self._decode_video_packet(video_packet)
if video_packet.image is not None or not skip_empty_frame:
break
if _debug:
print('Returning', video_packet)
return video_packet.image
def _get_start_time(self):
def streams():
format_context = self._file.context
for idx in (self._video_stream_index, self._audio_stream_index):
if idx is None:
continue
stream = format_context.contents.streams[idx].contents
yield stream
def start_times(streams):
yield 0
for stream in streams:
start = stream.start_time
if start == AV_NOPTS_VALUE:
yield 0
start_time = avutil.av_rescale_q(start,
stream.time_base,
AV_TIME_BASE_Q)
start_time = timestamp_from_ffmpeg(start_time)
yield start_time
return max(start_times(streams()))
@property
def audio_format(self):
return self._audio_format
@audio_format.setter
def audio_format(self, value):
self._audio_format = value
if value is None:
self.audioq.clear()
您将在此处感兴趣的行是self._file = ffmpeg_open_filename(asbytes_filename(filename))。这再次将我们带到media/codecs/ffmpeg.py：
def ffmpeg_open_filename(filename):
"""Open the media file.
:rtype: FFmpegFile
:return: The structure containing all the information for the media.
"""
file = FFmpegFile() # TODO: delete this structure and use directly AVFormatContext
result = avformat.avformat_open_input(byref(file.context),
filename,
None,
None)
if result != 0:
raise FFmpegException('Error opening file ' + filename.decode("utf8"))
result = avformat.avformat_find_stream_info(file.context, None)
if result < 0:
raise FFmpegException('Could not find stream info')
return file
事情变得一团糟：它调用ctypes函数（avformat_open_input），当给定文件时，它将获取其详细信息并填写FFmpegSource类所需的所有信息。通过一些工作，您应该能够使avformat_open_input接受一个字节对象，而不是将其打开以获取相同信息的文件路径。我很乐意这样做，并提供了一个可行的示例，但是我现在没有时间。然后，您需要使用新的avformat_open_input函数创建一个新的ffmpeg_open_filename函数，然后使用新的ffmpeg_open_filename函数创建一个新的FFmpegSource类。您现在所需要的就是利用新的FFmpegSource类的新的FFmpegDecoder类。
然后可以通过将其直接添加到pyglet包中来实现此目的。之后，您想在load（）函数（位于media/__init__.py中添加对字节对象参数的支持，并将解码器覆盖为新的解码器。在那里，您现在就可以流音频而无需保存它。
或者，您可以简单地使用已经支持它的软件包。 Python-vlc可以。您可以使用示例here来播放链接中想要的任何音频。如果您不只是为了挑战而这样做，我强烈建议您使用其他软件包。否则：祝你好运。