当然不是吃饱了撑着平白无故想这个问题，对这个问题的疑惑来自于Moblin平台上的Clutter Destop上一个GTK程序调用gtk_widget_show时的CoreDump问题，该GTK程序在Gnome Destop下运行正常。于是想，是不是3D的UI仍然依赖于XServer?

想深一层：Linux原有的XServer系统会接管屏幕的各种输入事件，例如，键盘、鼠标、触摸屏,其配置放在Xorg.conf中。这一点从Xerver的原理图及维基百科上对Xserver的描述可以了解到。an X server communicates with various client programs. The server accepts requests for graphical output (windows) and sends back user input (from keyboard, mouse, or touchscreen). 如果3D的应用不挂在XServer上，用户的输入事件如何到达应用？

在网上查找资料的时候发现了台湾黄敬群大牛的讲解的PPT《支援硬体加速的OPENGL/ES实做》，该大牛不愧为敬业乐群的好名字，技术精湛，乐于分享，读后深有启发。

GLX (OpenGL Extension to the X Window System)为X Windows System提供Open GL的扩展。因此3D的APP不是抛离X Server，而是与之共存。下图是敬群大牛PPT中GLX的图。

GLX包含了下面的内容：

1、X Window System application中的OpenGL API扩展

2、X 协议的扩展， 上图中的除了原有的Xpackets，新扩展一种GLX Packets。使客户端(the OpenGL application)发送 3D 渲染命令给 X server (the software responsible for the display)。 我的理解是，原有的X 协议不变基础上添加新的GLX扩展，因此，原有的用户事件输入处理流程是不变的。

3、X server的功能扩展，使之可以接收渲染命令。 (如果无硬件加速的OpenGL类库则使用 Mesa 类库)。

如果X Window System application和X server运行在同一台机器上，并且3D加速的图形卡及驱动能够支持，可以使用DRI(Direct Rendering Infrastructure)直接访问图形硬件设备。

直接的3D图形渲染和间接的3D图形渲染。如下图所示：

1、机器环境，某个牌子NetBook
uname -a
Linux localhost 2.6.29.1-18.1.moblin2-netbook #1 SMP PREEMPT Fri Apr 17 17:25:17 UTC 2009 i686 i686 i386 GNU/Linux

2.播放MP3

2.1运行gst -launch filesrc location="bb.mp3" ! mad ! alsasink 报错

2.2.下载、编译、安装 gst-plugins-ugly-0.10.11及libmad-0.15.1b，需要解决一些编译问题。前者包含了系列的ugly的plugins，包括GStreamer的mad，mad依赖于libmad-0.15.1b。

2.3、运行成功。能够正确听到MP3中的音乐。
[root@localhost shallon]# gst-launch -v filesrc location="bb.mp3" ! mad ! alsasink

Setting pipeline to PAUSED ...
/GstPipeline:pipeline0/GstMad:mad0.GstPad:src: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)32, depth=(int)32, rate=(int)44100, channels=(int)2
Pipeline is PREROLLING ...
/GstPipeline:pipeline0/GstAlsaSink:alsasink0.GstPad:sink: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)32, depth=(int)32, rate=(int)44100, channels=(int)2
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstAudioSinkClock
^CCaught interrupt -- handling interrupt.
Interrupt: Stopping pipeline ...
Execution ended after 6135758110 ns.
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
/GstPipeline:pipeline0/GstAlsaSink:alsasink0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstMad:mad0.GstPad:src: caps = NULL
Setting pipeline to NULL ...
FREEING pipeline ...

3、播放视频文件

3.1播放视频文件出错。 gst-launch -v filesrc location="cc.avi" ! decodebin ! xvimagesink

[root@localhost VERBATIM]# gst-launch -v filesrc location="cc.avi" ! decodebin ! xvimagesink

Setting pipeline to PAUSED ...
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src: caps = video/x-msvideo
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstAviDemux:avidemux0.GstPad:sink: caps = video/x-msvideo
Pipeline is PREROLLING ...
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstQueue:queue0.GstPad:sink: caps = audio/mpeg, mpegversion=(int)1, layer=(int)3, rate=(int)48000, channels=(int)2, codec_data=(buffer)010002000000800401007105
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstQueue:queue0.GstPad:src: caps = audio/mpeg, mpegversion=(int)1, layer=(int)3, rate=(int)48000, channels=(int)2, codec_data=(buffer)010002000000800401007105
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMPEGAudioParse:mpegaudioparse0.GstPad:sink: caps = audio/mpeg, mpegversion=(int)1, layer=(int)3, rate=(int)48000, channels=(int)2, codec_data=(buffer)010002000000800401007105
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMPEGAudioParse:mpegaudioparse0.GstPad:src: caps = audio/mpeg, mpegversion=(int)1, mpegaudioversion=(int)1, layer=(int)3, rate=(int)48000, channels=(int)2, parsed=(boolean)true
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMad:mad0.GstPad:sink: caps = audio/mpeg, mpegversion=(int)1, mpegaudioversion=(int)1, layer=(int)3, rate=(int)48000, channels=(int)2, parsed=(boolean)true
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)32, depth=(int)32, rate=(int)48000, channels=(int)2
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMad:mad0.GstPad:src: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)32, depth=(int)32, rate=(int)48000, channels=(int)2
ERROR: from element /GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstAviDemux:avidemux0: Internal data stream error.
Additional debug info:
gstavidemux.c(4163): gst_avi_demux_loop (): /GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstAviDemux:avidemux0:
streaming stopped, reason not-linked
ERROR: pipeline doesn't want to preroll.
Setting pipeline to NULL ...
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMad:mad0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMad:mad0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMPEGAudioParse:mpegaudioparse0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMPEGAudioParse:mpegaudioparse0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstQueue:queue0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstQueue:queue0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstAviDemux:avidemux0.GstPad:audio_00: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstAviDemux:avidemux0.GstPad:video_00: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstAviDemux:avidemux0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src: caps = NULL
FREEING pipeline ...
[root@localhost VERBATIM]#

3.2安装gst-ffmpeg-0.10.7

3.3运行gst-launch -v filesrc location="cc.avi" ! decodebin ! xvimagesink 成功看到连续的图像播放，但是无法听到声音

[root@localhost VERBATIM]# gst-launch -v filesrc location="cc.avi" ! decodebin ! xvimagesink Setting pipeline to PAUSED ...
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src: caps = video/x-msvideo
Pipeline is PREROLLING ...
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstAviDemux:avidemux0.GstPad:sink: caps = video/x-msvideo
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstQueue:queue0.GstPad:sink: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstQueue:queue0.GstPad:src: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstQueue:queue1.GstPad:sink: caps = audio/mpeg, mpegversion=(int)1, layer=(int)3, rate=(int)48000, channels=(int)2, codec_data=(buffer)010002000000800401007105
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstQueue:queue1.GstPad:src: caps = audio/mpeg, mpegversion=(int)1, layer=(int)3, rate=(int)48000, channels=(int)2, codec_data=(buffer)010002000000800401007105
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMPEGAudioParse:mpegaudioparse0.GstPad:sink: caps = audio/mpeg, mpegversion=(int)1, layer=(int)3, rate=(int)48000, channels=(int)2, codec_data=(buffer)010002000000800401007105
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_mpeg4:ffdec_mpeg40.GstPad:sink: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_mpeg4:ffdec_mpeg40.GstPad:src: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMPEGAudioParse:mpegaudioparse0.GstPad:src: caps = audio/mpeg, mpegversion=(int)1, mpegaudioversion=(int)1, layer=(int)3, rate=(int)48000, channels=(int)2, parsed=(boolean)true
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMad:mad0.GstPad:sink: caps = audio/mpeg, mpegversion=(int)1, mpegaudioversion=(int)1, layer=(int)3, rate=(int)48000, channels=(int)2, parsed=(boolean)true
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src1: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)32, depth=(int)32, rate=(int)48000, channels=(int)2
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMad:mad0.GstPad:src: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)32, depth=(int)32, rate=(int)48000, channels=(int)2
/GstPipeline:pipeline0/GstXvImageSink:xvimagesink0.GstPad:sink: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0.GstProxyPad:proxypad1: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
ERROR: from element /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0: Output window was closed
Additional debug info:
xvimagesink.c(1235): gst_xvimagesink_handle_xevents (): /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0
Execution ended after 24260868050 ns.
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
/GstPipeline:pipeline0/GstXvImageSink:xvimagesink0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src1: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src1: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMad:mad0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMad:mad0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMPEGAudioParse:mpegaudioparse0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstMPEGAudioParse:mpegaudioparse0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstQueue:queue1.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstQueue:queue1.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_mpeg4:ffdec_mpeg40.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_mpeg4:ffdec_mpeg40.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstQueue:queue0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstQueue:queue0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstAviDemux:avidemux0.GstPad:audio_00: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstAviDemux:avidemux0.GstPad:video_00: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstAviDemux:avidemux0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src: caps = NULL
Setting pipeline to NULL ...
FREEING pipeline ...
[root@localhost VERBATIM]#

3.4 使用avidemux同时播放语音和图像

[root@localhost VERBATIM]# gst-launch -v filesrc location=cc.avi ! avidemux name=demux demux.audio_00 ! mad ! alsasink demux.video_00 ! queue ! decodebin ! ffmpegcolorspace ! videoscale ! xvimagesink

Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
/GstPipeline:pipeline0/GstQueue:queue0.GstPad:sink: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstQueue:queue0.GstPad:src: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstMad:mad0.GstPad:sink: caps = audio/mpeg, mpegversion=(int)1, layer=(int)3, rate=(int)48000, channels=(int)2, codec_data=(buffer)010002000000800401007105
/GstPipeline:pipeline0/GstMad:mad0.GstPad:src: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)32, depth=(int)32, rate=(int)48000, channels=(int)2
/GstPipeline:pipeline0/GstAlsaSink:alsasink0.GstPad:sink: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)32, depth=(int)32, rate=(int)48000, channels=(int)2
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:sink: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink.GstProxyPad:proxypad0: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_mpeg4:ffdec_mpeg40.GstPad:sink: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_mpeg4:ffdec_mpeg40.GstPad:src: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstFFMpegCsp:ffmpegcsp0.GstPad:src: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstFFMpegCsp:ffmpegcsp0.GstPad:sink: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0.GstProxyPad:proxypad1: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstVideoScale:videoscale0.GstPad:src: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstVideoScale:videoscale0.GstPad:sink: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstXvImageSink:xvimagesink0.GstPad:sink: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstAudioSinkClock
ERROR: from element /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0: Output window was closed
Additional debug info:
xvimagesink.c(1235): gst_xvimagesink_handle_xevents (): /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0
Execution ended after 40043404401 ns.
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
/GstPipeline:pipeline0/GstXvImageSink:xvimagesink0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstAlsaSink:alsasink0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstVideoScale:videoscale0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstVideoScale:videoscale0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstMad:mad0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstMad:mad0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstFFMpegCsp:ffmpegcsp0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstFFMpegCsp:ffmpegcsp0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_mpeg4:ffdec_mpeg40.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_mpeg4:ffdec_mpeg40.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink: caps = NULL
/GstPipeline:pipeline0/GstQueue:queue0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstQueue:queue0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstAviDemux:demux.GstPad:audio_00: caps = NULL
/GstPipeline:pipeline0/GstAviDemux:demux.GstPad:video_00: caps = NULL
Setting pipeline to NULL ...
FREEING pipeline ...
[root@localhost VERBATIM]#

3.5 使用avidemux同时播放语音和图像，所谓的gst-launch 的{} 能够使{}中间部分运行在单独的线程中。

[root@localhost VERBATIM]# gst-launch -v filesrc location=cc.avi ! avidemux name=demux demux.audio_00 ! mad ! alsasink {demux.video_00 ! queue ! decodebin ! ffmpegcolorspace ! videoscale ! xvimagesink}

Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
/GstPipeline:pipeline0/GstQueue:queue0.GstPad:sink: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstQueue:queue0.GstPad:src: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstMad:mad0.GstPad:sink: caps = audio/mpeg, mpegversion=(int)1, layer=(int)3, rate=(int)48000, channels=(int)2, codec_data=(buffer)010002000000800401007105
/GstPipeline:pipeline0/GstMad:mad0.GstPad:src: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)32, depth=(int)32, rate=(int)48000, channels=(int)2
/GstPipeline:pipeline0/GstAlsaSink:alsasink0.GstPad:sink: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)32, depth=(int)32, rate=(int)48000, channels=(int)2
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:sink: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink.GstProxyPad:proxypad0: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_mpeg4:ffdec_mpeg40.GstPad:sink: caps = video/x-divx, divxversion=(int)5, framerate=(fraction)30000/1001, width=(int)720, height=(int)480
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_mpeg4:ffdec_mpeg40.GstPad:src: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstFFMpegCsp:ffmpegcsp0.GstPad:src: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstFFMpegCsp:ffmpegcsp0.GstPad:sink: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0.GstProxyPad:proxypad1: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstVideoScale:videoscale0.GstPad:src: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstVideoScale:videoscale0.GstPad:sink: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
/GstPipeline:pipeline0/GstXvImageSink:xvimagesink0.GstPad:sink: caps = video/x-raw-yuv, width=(int)720, height=(int)480, framerate=(fraction)30000/1001, format=(fourcc)I420, pixel-aspect-ratio=(fraction)1/1
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstAudioSinkClock
ERROR: from element /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0: Output window was closed
Additional debug info:
xvimagesink.c(1235): gst_xvimagesink_handle_xevents (): /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0
Execution ended after 14081223436 ns.
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
/GstPipeline:pipeline0/GstXvImageSink:xvimagesink0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstAlsaSink:alsasink0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstVideoScale:videoscale0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstVideoScale:videoscale0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstMad:mad0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstMad:mad0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstFFMpegCsp:ffmpegcsp0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstFFMpegCsp:ffmpegcsp0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_mpeg4:ffdec_mpeg40.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_mpeg4:ffdec_mpeg40.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink: caps = NULL
/GstPipeline:pipeline0/GstQueue:queue0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstQueue:queue0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstAviDemux:demux.GstPad:audio_00: caps = NULL
/GstPipeline:pipeline0/GstAviDemux:demux.GstPad:video_00: caps = NULL
Setting pipeline to NULL ...
FREEING pipeline ...
[root@localhost VERBATIM]#