video-streaming - 使用GStreamer播放传入的RTP流

Question

我正在开发GStreamer应用程序，并为实现传入RTP流的播放器而苦苦挣扎。我正在尝试围绕gstrtpbin元素构建管道。我正在尝试使用gst-launch构造对管道进行建模:

VIDEO_CAPS="application/x-rtp,media=(string)video,clock-rate=(int)90000,encoding-name=(string)H264"

gst-launch -v udpsrc caps=$VIDEO_CAPS port=4444 \
              ! gstrtpbin .recv_rtp_sink_0 \
              ! rtph264depay ! ffdec_h264 ! xvimagesink

当我启动脚本时，GStreamer会报告以下错误:

Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpSession:rtpsession0: ntp-ns-base = 3469468914024449000
New clock: GstSystemClock
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpSession:rtpsession0.GstPad:recv_rtp_sink: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264
/GstPipeline:pipeline0/GstRtpBin:rtpbin0.GstGhostPad:recv_rtp_sink_0: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264
/GstPipeline:pipeline0/GstRtpBin:rtpbin0.GstGhostPad:recv_rtp_sink_0.GstProxyPad:proxypad0: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpSession:rtpsession0.GstPad:recv_rtp_src: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpSsrcDemux:rtpssrcdemux0.GstPad:sink: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpJitterBuffer:rtpjitterbuffer0.GstPad:src: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpJitterBuffer:rtpjitterbuffer0.GstPad:sink: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpPtDemux:rtpptdemux0.GstPad:sink: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264
/GstPipeline:pipeline0/GstRtpBin:rtpbin0.GstGhostPad:recv_rtp_src_0_960476599_33.GstProxyPad:proxypad1: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264, payload=(int)33
ERROR: from element /GstPipeline:pipeline0/GstUDPSrc:udpsrc0: Internal data flow error.
Additional debug info:
gstbasesrc.c(2378): gst_base_src_loop (): /GstPipeline:pipeline0/GstUDPSrc:udpsrc0:
streaming task paused, reason not-linked (-1)
Execution ended after 209381685 ns.
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
/GstPipeline:pipeline0/GstRtpBin:rtpbin0.GstGhostPad:recv_rtp_src_0_960476599_33: caps = NULL
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpPtDemux:rtpptdemux0.GstPad:src_33: caps = NULL
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpPtDemux:rtpptdemux0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpJitterBuffer:rtpjitterbuffer0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpJitterBuffer:rtpjitterbuffer0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpSsrcDemux:rtpssrcdemux0.GstPad:src_960476599: caps = NULL
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpSsrcDemux:rtpssrcdemux0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpSession:rtpsession0.GstPad:recv_rtp_src: caps = NULL
/GstPipeline:pipeline0/GstRtpBin:rtpbin0/GstRtpSession:rtpsession0.GstPad:recv_rtp_sink: caps = NULL
/GstPipeline:pipeline0/GstRtpBin:rtpbin0.GstGhostPad:recv_rtp_sink_0: caps = NULL
/GstPipeline:pipeline0/GstUDPSrc:udpsrc0.GstPad:src: caps = NULL
Setting pipeline to NULL ...
Freeing pipeline ...

我应该提及的是，它可以与playbin和SDP文件一起使用。例如，此文件:

v=0
o=- 1188340656180883 1 IN IP4 127.0.0.1
s=Session streamed by GStreamer
i=server.sh
t=0 0
a=tool:GStreamer
a=type:broadcast
m=video 4444 RTP/AVP 96
c=IN IP4 127.0.0.1
a=rtpmap:96 H264/90000

可以像这样播放视频流:

gst-launch -vvv playbin uri=file://`pwd`/stream.sdp

为了完整性:我正在使用VLC发送数据。这是命令:

vlc -I rc /usr/local/movies/sample.mp4 \
    --screen-fps=10 :screen-caching=100 \
    --sout='#transcode{vcodec=h264,venc=x264{bframes=0,keyint=40},vb=512}:\
                   rtp{mux=ts,dst=127.0.0.1,port=4444}'

有人可以帮助我理解为什么gst-launch脚本失败吗？错误“原因未链接”使我认为gstrtpbin和rtph264depay元素之间的链接已断开。但是我不知道如何解决它。

编辑
按照RAOF的建议，我修复了命令中的一些错误。但是我使用的是ffdec_h264和autovideosink，因为在我的Windows系统上，我没有安装fluh264dec和xvimage接收器插件:

gst-launch-0.10 udpsrc port=4444 caps="application/x-rtp,media=(string)video,clock-rate=(int)90000,encoding-name=(string)H264" ! .recv_rtp_sink_0 gstrtpbin ! rtpmp2tdepay ! mpegtsdemux ! ffdec_h264 ! autovideosink 

导致新的错误:

0:00:00.743000000   516   024070A8 ERROR                 ffmpeg .:0:: non-existing PPS referenced
0:00:00.744000000   516   024070A8 ERROR                 ffmpeg .:0:: non-existing PPS referenced
0:00:00.745000000   516   024070A8 ERROR                 ffmpeg .:0:: decode_slice_header error
0:00:00.745000000   516   024070A8 ERROR                 ffmpeg .:0:: no frame!
0:00:00.812000000   516   024070A8 ERROR                 ffmpeg .:0:: non-existing PPS referenced
0:00:00.813000000   516   024070A8 ERROR                 ffmpeg .:0:: non-existi
...
ERROR: from element /GstPipeline:pipeline0/GstUDPSrc:udpsrc0: Internal data flow
 error.
Additional debug info:
..\Source\gstreamer\libs\gst\base\gstbasesrc.c(2378): gst_base_src_loop (): /Gst
Pipeline:pipeline0/GstUDPSrc:udpsrc0:
streaming task paused, reason not-negotiated (-4)
Execution ended after 4790000000 ns.
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
Setting pipeline to NULL ...
Freeing pipeline ...

我仍在尝试找出解决方法。如果可以提供帮助，请随时提供帮助。

编辑2
我再次使用SDP解决方案进行了测试，发现“不存在的PPS”错误也会发生，但是视频确实可以播放。另一方面，致命的“内部数据流错误”仅在使用自定义管道解决方案时显示。
我怀疑“不存在的PPS”错误是由x264编码器引起的。 “内部数据流错误”必须由我的管道中的错误或某些Windows插件中的错误引起。我会做一些进一步的研究...

Answer 1

据我所知，您有两个问题:

首先，接收器规范的顺序似乎很重要:您需要... ! gstrtpbin .recv_rtp_sink_0 ! ...而不是... ! .recv_rtp_sink_0 gstrtpbin ! ...。

其次，vlc正在发送MPEG2传输流-您已在rtp流输出描述符中添加了mux=ts-但您正尝试对原始h264流进行有效负载处理。您需要先卸载ts流，然后再对其进行解复用以获取h264流数据。

所以，最后，管道

gst-launch-0.10 -v udpsrc port=4444 \
caps="application/x-rtp,media=(string)video,clock-rate=(int)90000,encoding-name=(string)H264" \
! .recv_rtp_sink_0 gstrtpbin ! rtpmp2tdepay \
! mpegtsdemux ! fluh264dec ! xvimagesink

使用TS demuxer(mpegtsdemux)和h264解码器(fluh264dec)为我工作。