Gstreamer rtspsrc+decodebin 对比 uridecodebin

Question

考虑以下 gstreamer 命令(我正在 Windows 中尝试它们):

1. gst-launch-1.0 rtspsrc location=rtsp://<path-to-stream> ! decodebin ! autovideosink
   

2. gst-launch-1.0 uridecodebin uri=rtsp://<path-to-stream> ! autovideosink
   

这两个命令都应该在自动创建的窗口上播放视频。但就我而言，第一个只能在 5 次尝试中的 1 次开始播放。而第二个每次都有效。

如果失败，第一个命令会打印出以下消息:

Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Progress: (open) Opening Stream
Progress: (connect) Connecting to rtsp://<path-to-stream-here>
Progress: (open) Retrieving server options
Progress: (open) Retrieving media info
Progress: (request) SETUP stream 0
Progress: (request) SETUP stream 1
Progress: (open) Opened Stream
Setting pipeline to PLAYING ...
New clock: GstSystemClock
Progress: (request) Sending PLAY request
Progress: (request) Sending PLAY request
Progress: (request) Sent PLAY request
WARNING: from element /GstPipeline:pipeline0/GstDecodeBin:decodebin0: Delayed linking failed.
Additional debug info:
./grammar.y(506): gst_parse_no_more_pads (): /GstPipeline:pipeline0/GstDecodeBin:decodebin0:
failed delayed linking some pad of GstDecodeBin named decodebin0 to some pad of 
GstAutoVideoSink named autovideosink0
ERROR: from element /GstPipeline:pipeline0/GstRTSPSrc:rtspsrc0/GstUDPSrc:udpsrc0: Internal data flow error.
Additional debug info:
gstbasesrc.c(2948): gst_base_src_loop (): /GstPipeline:pipeline0/GstRTSPSrc:rtsp
src0/GstUDPSrc:udpsrc0:
streaming task paused, reason not-linked (-1)
Execution ended after 0:00:02.289918784
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
Setting pipeline to NULL ...
Freeing pipeline ...

从用户的角度来看，这些命令之间的主要区别是什么？是否有可能使第一个命令更可靠(即像第二个命令一样无错误地工作)？

Answer 1

是否设置了其他属性，例如caps="application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264"。如果参数不匹配，就会报错!