Ubuntu 14.04 Gstreamer 自动视频接收器

Question

我正在尝试让 Gstreamer 视频流在 Ubuntu 14.04 上运行，但接收端无法正确显示视频。我有一个发送 MJPEG 图像的发送器管道，我这样开始：

gst-launch-1.0 -v videotestsrc ! jpegenc ! rtpjpegpay ! udpsink host=127.0.0.1 port=5200

输出是：

Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
/GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0.GstPad:src: caps = video/x-raw, width=(int)320, height=(int)240, framerate=(fraction)30/1, format=(string)I420, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
/GstPipeline:pipeline0/GstJpegEnc:jpegenc0.GstPad:sink: caps = video/x-raw, width=(int)320, height=(int)240, framerate=(fraction)30/1, format=(string)I420, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
/GstPipeline:pipeline0/GstJpegEnc:jpegenc0.GstPad:src: caps = image/jpeg, sof-marker=(int)0, width=(int)320, height=(int)240, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1
/GstPipeline:pipeline0/GstRtpJPEGPay:rtpjpegpay0.GstPad:src: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)JPEG, a-framerate=(string)30.000000, a-framesize=(string)320-240, payload=(int)96, ssrc=(uint)1970481773, timestamp-offset=(uint)1012832172, seqnum-offset=(uint)21614
/GstPipeline:pipeline0/GstUDPSink:udpsink0.GstPad:sink: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)JPEG, a-framerate=(string)30.000000, a-framesize=(string)320-240, payload=(int)96, ssrc=(uint)1970481773, timestamp-offset=(uint)1012832172, seqnum-offset=(uint)21614
/GstPipeline:pipeline0/GstRtpJPEGPay:rtpjpegpay0.GstPad:sink: caps = image/jpeg, sof-marker=(int)0, width=(int)320, height=(int)240, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1
/GstPipeline:pipeline0/GstRtpJPEGPay:rtpjpegpay0: timestamp = 1012832172
/GstPipeline:pipeline0/GstRtpJPEGPay:rtpjpegpay0: seqnum = 21614
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock

接收管道是：

gst-launch-1.0 udpsrc port=5200 caps="application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)JPEG, a-framerate=(string)30.000000, a-framesize=(string)320-240, payload=(int)96" ! rtpjpegdepay ! jpegdec ! xvimagesink

请注意，我已从发件人信息中复制了大写字母。

但是，我不断收到“无法发送粘性事件”错误，并且接收器立即终止。我可能做错了什么？我的输出如下：

Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
0:00:00.016961467 12229      0x266a400 WARN                GST_PADS gstpad.c:3669:gst_pad_peer_query:<jpegdec0:src> could not send sticky events
0:00:00.017297845 12229      0x266a400 WARN                 basesrc gstbasesrc.c:2865:gst_base_src_loop:<udpsrc0> error: Internal data flow error.
0:00:00.017306308 12229      0x266a400 WARN                 basesrc gstbasesrc.c:2865:gst_base_src_loop:<udpsrc0> error: streaming task paused, reason not-negotiated (-4)
ERROR: from element /GstPipeline:pipeline0/GstUDPSrc:udpsrc0: Internal data flow error.
Additional debug info:
gstbasesrc.c(2865): gst_base_src_loop (): /GstPipeline:pipeline0/GstUDPSrc:udpsrc0:
streaming task paused, reason not-negotiated (-4)
Execution ended after 0:00:00.000651039
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
Setting pipeline to NULL ...
Freeing pipeline ...

我尝试了 autovideosink、ximagesink，结果相同。

谢谢。

Answer 1

好吧，你只需要添加 videoconvert - jpegdec 生成 xvimagesink 不理解的视频：

gst-launch-1.0 udpsrc port=5200 ! application/x-rtp\,\ media\=\(string\)video\,\ clock-rate\=\(int\)90000\,\ encoding-name\=\(string\)JPEG\,\ a-framerate\=\(string\)\"30\\\,000000\"\,\ payload\=\(int\)26\,\ ssrc\=\(uint\)2512101225\,\ timestamp-offset\=\(uint\)1627080146\,\ seqnum-offset\=\(uint\)4727 ! rtpjpegdepay ! jpegdec ! videoconvert ! xvimagesink

我是怎么想出来的？通过这种方式使用 fakesink：

udpsrc ! fakesink -v

工作，然后

udpsrc ! rptjpegdepay ! fakesink 

再次工作..所以我继续这样，发现问题确实出在 xvimagesink 中.. 奇怪的是我们没有收到更明确的错误消息..

您还可以使用以下方法调试应用程序：

GST_DEBUG=4 gst-launch-1.0 udpsrc .....

您可以滚动到未协商的部分并环顾四周。