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我正在尝试实现一个简单的管道，该管道可以通过使用 python 的gstreamer终端命令（）正常工作。gst-launch-1.0 filesrc location=sample.264 ! h264parse ! decodebin ! videoconvert ! autovideosink这是我的完整代码：

import sys
import platform
import configparser

import gi

gi.require_version('Gst', '1.0')

from gi.repository import GObject, Gst, GLib

def bus_call(bus, message, loop):
    t = message.type
    if t == Gst.MessageType.EOS:
        sys.stdout.write("End-of-stream\n")
        loop.quit()
    elif t==Gst.MessageType.WARNING:
        err, debug = message.parse_warning()
        sys.stderr.write("Warning: %s: %s\n" % (err, debug))
    elif t == Gst.MessageType.ERROR:
        err, debug = message.parse_error()
        sys.stderr.write("Error: %s: %s\n" % (err, debug))
        loop.quit()
    return True

def main(args):
    if len(args) != 2:
        sys.stderr.write("usage: %s <media file or uri>\n" % args[0])
        sys.exit(1)
        
    GObject.threads_init()
    Gst.init(None)
    
    print("Creating Pipeline \n ")
    pipeline = Gst.Pipeline()
    
    if not pipeline:
        sys.stderr.write(" Unable to create Pipeline \n")
        
    print("Creating Source \n ")
    source = Gst.ElementFactory.make("filesrc", "file-source")
    if not source:
        sys.stderr.write(" Unable to create Source \n")
    
    print("Creating H264Parser \n")
    h264parser = Gst.ElementFactory.make("h264parse", "h264-parser")
    if not h264parser:
        sys.stderr.write(" Unable to create h264 parser \n")
        
    print("Creating Decoder \n ")
    decoder = Gst.ElementFactory.make("decodebin", "decode")
    if not decoder:
        sys.stderr.write(" Unable to create Decode \n")
        
    print("Creating Video Converter \n ")
    converter = Gst.ElementFactory.make("videoconvert", "converter")
    if not source:
        sys.stderr.write(" Unable to create Video Converter \n")
        
    print("Creating Sink \n ")
    sink = Gst.ElementFactory.make("autovideosink", "video-sink")
    if not source:
        sys.stderr.write(" Unable to create Sink \n")
        
    print("Playing file %s " %args[1])
    source.set_property('location', args[1])
    
    print("Adding elements to Pipeline \n")
    pipeline.add(source)
    pipeline.add(h264parser)
    pipeline.add(decoder)
    pipeline.add(converter)
    pipeline.add(sink)
    
    print("Linking elements in the Pipeline \n")
    source.link(h264parser)
    h264parser.link(decoder)
    decoder.link(converter)
    converter.link(sink)
    
    loop = GLib.MainLoop()
    
    bus = pipeline.get_bus()
    bus.add_signal_watch()
    bus.connect ("message", bus_call, loop)
    
    print("Starting pipeline \n")
    
    pipeline.set_state(Gst.State.PLAYING)
    try:
        loop.run()
    except:
        pass
        
    pipeline.set_state(Gst.State.NULL)
    
if __name__ == '__main__':
    sys.exit(main(sys.argv))

当我运行此脚本时，终端在启动管道后显示错误：

Error: gst-stream-error-quark: Internal data stream error. (1): gstbaseparse.c(3634): gst_base_parse_loop (): /GstPipeline:pipeline0/GstH264Parse:h264-parser:
streaming stopped, reason not-linked (-1)

这是完整的终端输出：

sudo python3 pipe.py sample.264

Creating Pipeline 
 
Creating Source 
 
Creating H264Parser 

Creating Decoder 
 
Creating Video Converter 
 
Creating Sink 
 
Playing file sample.264 
Adding elements to Pipeline 

Linking elements in the Pipeline 

Starting pipeline 

Error: gst-stream-error-quark: Internal data stream error. (1): gstbaseparse.c(3634): gst_base_parse_loop (): /GstPipeline:pipeline0/GstH264Parse:h264-parser:
streaming stopped, reason not-linked (-1)

有没有办法解决这个问题？

4

1 回答 1

1

使用便捷功能（如gst_parse_launch(). 这将使用您提供给的相同语法构造管道gst-launch-1.0。

在 python 和你的例子中，沿着这个：

pipeline = Gst.parse_launch("filesrc location=sample.264 ! h264parse ! decodebin ! videoconvert ! autovideosink")

您可以在该管道上设置总线回调并将其设置为 PLAYING 等，就像您在示例中所做的那样。

对原始代码的一些解释：您使用decodebin元素。一旦管道运行，那个只会暴露焊盘。所以你不能在此之前将它链接到任何东西。这是必须通过挂钩回调手动完成的事情。

如需进一步阅读动态管道示例：

https://gstreamer.freedesktop.org/documentation/tutorials/basic/dynamic-pipelines.html?gi-language=c

gst-launch-1.0以及在gst_parse_launch()内部为您自动创建此逻辑。

于 2020-11-18T08:46:38.313 回答