使用 (Python) Gstreamer 解码音频（为 PCM 数据）
我正在编写一个使用 Python Gstreamer 绑定来播放音频的应用程序，但我现在也尝试解码音频 - 也就是说，我想使用 decodebin 并接收原始 PCM 缓冲区。具体来说，我想增量读取文件的块，而不是将整个文件读入内存。
一些具体问题：我如何使用 Gstreamer 来完成此任务？特别是 pygst 吗？我需要使用特定的“接收器”元素来从流中读取数据吗？是否有从 pygst Buffer 读取数据的首选方法对象？如何控制消耗数据的速率（而不是仅仅进入“主循环”）？
I'm writing an application that uses the Python Gstreamer bindings to play audio, but I'm now trying to also just decode audio -- that is, I'd like to read data using a decodebin and receive a raw PCM buffer. Specifically, I want to read chunks of the file incrementally rather than reading the whole file into memory.
Some specific questions: How can I accomplish this with Gstreamer? With pygst specifically? Is there a particular "sink" element I need to use to read data from the stream? Is there a preferred way to read data from a pygst Buffer object? How do I go about controlling the rate at which I consume data (rather than just entering a "main loop")?
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要将数据返回到应用程序中，推荐的方法是 appsink。
基于一个简单的音频播放器，例如这个（并替换oggdemux/vorbisdec 通过decodebin & capsfilter with caps = "audio/x-raw-int")，将autoaudiosink更改为appsink，并连接"new-buffer" 向 python 函数发送信号+ 将“发出信号”设置为 True。该函数将接收解码后的 PCM/int 数据块。解码的速率取决于您可以解码和消费的速率。由于 new-buffer 信号位于 Gstreamer 线程上下文中，因此您可以在该函数中休眠/等待来控制或减慢解码速度。
To get the data back in your application, the recommended way is appsink.
Based on a simple audio player like this one (and replace the oggdemux/vorbisdec by decodebin & capsfilter with caps = "audio/x-raw-int"), change autoaudiosink to appsink, and connect "new-buffer" signal to a python function + set "emit-signals" to True. The function will receive decoded chunks of PCM/int data. The rate of the decoding will depend on the rate at which you can decode and consume. Since the new-buffer signal is in the Gstreamer thread context, you could just sleep/wait in that function to control or slow down the decoding speed.