我写了一个使用 Adder
的小 Python 脚本将两个源流混合在一起的插件。
启动程序后,您会听到 audiotestsrc
生成的 1kHz 音调插入。当您按 Enter 时,另一个 500Hz 测试音连接到 Adder
所以你听到他们在一起。 (顺便说一句,我真的不明白为什么我应该在这里再次将管道设置为播放状态以听到混音。有什么方法可以插入新源而无需重新启动管道?)
当您再次按下 Enter 时,1kHz 音调应该从混音中移除,500Hz 音调应该继续播放,但我再也听不到任何声音了。我得到一个pulse pulsesink.c:528:gst_pulsering_stream_underflow_cb:<pulseaudio_output> Got underflow
在调试输出中作为最后一行。我真的不知道接下来要尝试什么。
这里是完整的源代码:
#!/usr/bin/python
# On-the-go source removal doesn't work this way with GStreamer. Why?
import gobject;
gobject.threads_init()
import gst;
if __name__ == "__main__":
pipe = gst.Pipeline("mypipe")
adder = gst.element_factory_make("adder","audiomixer")
pipe.add(adder)
buzzer = gst.element_factory_make("audiotestsrc","buzzer")
buzzer.set_property("freq",1000)
pipe.add(buzzer)
pulse = gst.element_factory_make("pulsesink", "pulseaudio_output")
pipe.add(pulse)
buzzer.link(adder)
adder.link(pulse)
pipe.set_state(gst.STATE_PLAYING)
raw_input("1kHz test sound. Press <ENTER> to continue.")
buzzer2=gst.element_factory_make("audiotestsrc","buzzer2")
buzzer2.set_property("freq",500)
pipe.add(buzzer2)
buzzer2.link(adder)
pipe.set_state(gst.STATE_PLAYING)
raw_input("1kHz + 500Hz test sound playing simoultenously. Press <ENTER> to continue.")
buzzer.unlink(adder)
pipe.set_state(gst.STATE_PLAYING)
raw_input("Only 500Hz test sound. Press <ENTER> to stop.")
最佳答案
我自己找到了解决方案。我必须将请求板与 Adder
一起使用并使用 pad blocking GStreamer 的能力。
这是带有一些描述的工作源代码:
#!/usr/bin/python
import gobject;
gobject.threads_init()
import gst;
if __name__ == "__main__":
# First create our pipeline
pipe = gst.Pipeline("mypipe")
# Create a software mixer with "Adder"
adder = gst.element_factory_make("adder","audiomixer")
pipe.add(adder)
# Gather a request sink pad on the mixer
sinkpad1=adder.get_request_pad("sink%d")
# Create the first buzzer..
buzzer1 = gst.element_factory_make("audiotestsrc","buzzer1")
buzzer1.set_property("freq",1000)
pipe.add(buzzer1)
# .. and connect it's source pad to the previously gathered request pad
buzzersrc1=buzzer1.get_pad("src")
buzzersrc1.link(sinkpad1)
# Add some output
output = gst.element_factory_make("autoaudiosink", "audio_out")
pipe.add(output)
adder.link(output)
# Start the playback
pipe.set_state(gst.STATE_PLAYING)
raw_input("1kHz test sound. Press <ENTER> to continue.")
# Get an another request sink pad on the mixer
sinkpad2=adder.get_request_pad("sink%d")
# Create an another buzzer and connect it the same way
buzzer2 = gst.element_factory_make("audiotestsrc","buzzer2")
buzzer2.set_property("freq",500)
pipe.add(buzzer2)
buzzersrc2=buzzer2.get_pad("src")
buzzersrc2.link(sinkpad2)
# Start the second buzzer (other ways streaming stops because of starvation)
buzzer2.set_state(gst.STATE_PLAYING)
raw_input("1kHz + 500Hz test sound playing simoultenously. Press <ENTER> to continue.")
# Before removing a source, we must use pad blocking to prevent state changes
buzzersrc1.set_blocked(True)
# Stop the first buzzer
buzzer1.set_state(gst.STATE_NULL)
# Unlink from the mixer
buzzersrc1.unlink(sinkpad1)
# Release the mixers first sink pad
adder.release_request_pad(sinkpad1)
# Because here none of the Adder's sink pads block, streaming continues
raw_input("Only 500Hz test sound. Press <ENTER> to stop.")
关于python - 随时随地向 GStreamer 管道添加和删除音频源,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3899666/