使用Gtreamer获得摄像头数据并显示(Webcam streaming using Python--pyGTK, wxPython and Gstreamer)

1. 使用gst-launch工具测试摄像头能否使用，在终端中键入命令如下：

gst-launch v4l2src ! autovideosink

这样就可以看到摄像头中的自己了，效果如下图所示：

 

2. 使用 python脚本实现

使用gst-launch工具，只是为了测试摄像头是否能用，以及所使用的管道。强烈建议在用具体的语言实现Gstreamer前，用gst-launch工具做一些简单的测试。

如果我们要做一个视频聊天的软件，我们更需要对输出的视频进行控制，比如在指定的GUI中显示，控制视频大小等等，下面的代码使用pyGTK实现的在一个window里面显示视频：

参考链接：http://pygstdocs.berlios.de/pygst-tutorial/webcam-viewer.html

部分代码略有改动

 

import sys, os
import pygtk, gtk, gobject
import pygst
pygst.require("0.10")
import gst
class GTK_Main:
    def __init__(self):
        window = gtk.Window(gtk.WINDOW_TOPLEVEL)
        window.set_title("Webcam-Viewer")
        window.set_default_size(500, 400)
        window.connect("destroy", gtk.main_quit, "WM destroy")
        vbox = gtk.VBox()
        window.add(vbox)
        self.movie_window = gtk.DrawingArea()
        vbox.add(self.movie_window)
        hbox = gtk.HBox()
        vbox.pack_start(hbox, False)
        hbox.set_border_width(10)
        hbox.pack_start(gtk.Label())
        self.button = gtk.Button("Start")
        self.button.connect("clicked", self.start_stop)
        hbox.pack_start(self.button, False)
        self.button2 = gtk.Button("Quit")
        self.button2.connect("clicked", self.exit)
        hbox.pack_start(self.button2, False)
        hbox.add(gtk.Label())
        window.show_all()
        # Set up the gstreamer pipeline
        #self.player = gst.parse_launch ("v4l2src ! autovideosink")
        self.player = gst.Pipeline("pipeline")
        src = gst.element_factory_make("v4l2src", "source")
        self.player.add(src)
        vsink = gst.element_factory_make("autovideosink", "video-sink")
        self.player.add(vsink)
        src.link(vsink)
        bus = self.player.get_bus()
        bus.add_signal_watch()
        bus.enable_sync_message_emission()
        bus.connect("message", self.on_message)
        bus.connect("sync-message::element", self.on_sync_message)
    def start_stop(self, w):
        if self.button.get_label() == "Start":
            self.button.set_label("Stop")
            self.player.set_state(gst.STATE_PLAYING)
        else:
            self.player.set_state(gst.STATE_NULL)
            self.button.set_label("Start")
    def exit(self, widget, data=None):
        gtk.main_quit()
    def on_message(self, bus, message):
        t = message.type
        if t == gst.MESSAGE_EOS:
            self.player.set_state(gst.STATE_NULL)
            self.button.set_label("Start")
        elif t == gst.MESSAGE_ERROR:
            err, debug = message.parse_error()
            print "Error: %s" % err, debug
            self.player.set_state(gst.STATE_NULL)
            self.button.set_label("Start")
    def on_sync_message(self, bus, message):
        if message.structure is None:
            return
        message_name = message.structure.get_name()
        if message_name == "prepare-xwindow-id":
            # Assign the viewport
            imagesink = message.src
            imagesink.set_property("force-aspect-ratio", True)
            imagesink.set_xwindow_id(self.movie_window.window.xid)
GTK_Main()
gtk.gdk.threads_init()
gtk.main()

运行结果图如下：

 

使用wxPython重写代码如下：

"""rewrite the serweb.py code with wxpython"""
import sys, os
import pygtk, gtk, gobject
import pygst
pygst.require("0.10")
import gst
import wx

class Frame(wx.Frame):
    """Frame class that displays an image."""
    def __init__(self, parent=None, id=-1,
                 pos=wx.DefaultPosition, title='Hello, wxPython!'):
        wx.Frame.__init__(self, parent, id, title, pos, (400,300))
        #self.windows = wx.PaintDC(self)
        self.Bind(wx.EVT_CLOSE, self.OnCloseWindow)
        self.player = gst.parse_launch ("v4l2src ! autovideosink")
        bus = self.player.get_bus()
        bus.add_signal_watch()
        bus.enable_sync_message_emission()
        bus.connect("message", self.on_message)
        bus.connect("sync-message::element", self.on_sync_message)
        self.player.set_state(gst.STATE_PLAYING)
    def OnCloseWindow(self, event):
        self.player.set_state(gst.STATE_NULL);
        event.Skip()
    def on_message(self, bus, message):
        t = message.type
        if t == gst.MESSAGE_EOS:
            self.player.set_state(gst.STATE_NULL)
        elif t == gst.MESSAGE_ERROR:
            err, debug = message.parse_error()
            print "Error: %s" % err, debug
            self.player.set_state(gst.STATE_NULL)
    def on_sync_message(self, bus, message):
        if message.structure is None:
            return
        message_name = message.structure.get_name()
        if message_name == "prepare-xwindow-id":
            # Assign the viewport
            imagesink = message.src
            imagesink.set_property("force-aspect-ratio", True)
            imagesink.set_xwindow_id(self.GetHandle())
class App(wx.App):
    """Application class."""
    def OnInit(self):
        self.frame = Frame()
        self.frame.Show()
        self.SetTopWindow(self.frame)
        return True
def main():
    gtk.gdk.threads_init()
    app = App()
    app.MainLoop()
if __name__ == '__main__':
    main()

运行结果如下：

分享到：