GStreamer pipeline to show an RTSP stream

Question

I am pretty new to Gstreamer.

I need to write a video client able to stream data from an RTSP source using GStreamer. I configured VLC to stream a video I have on my laptop using RTSP and I want to create a pipeline to get that stream and show it. I tried using playbin and everything works fine. The point is that I need to fine tune the latency used to stream the video but it seems I cannot do that with playbin.

I tried rtspsrc because it allows to work on the latency but I don't know how to show the video on any window. That's the pipeline I created:

gst-launch-1.0 rtspsrc location=rtsp://localhost:8554/test latency=300 ! decodebin ! autovideosink

I get the error "streaming task paused, reason not-negotiated (-4)".

I tried different pipelines after deeply looking on the internet but I definitely miss something. How can I write a gstreamer pipeline to show a video from RTSP?

The final goal is to have a pipeline which can be adjustable at least in terms of latency, so I have two choices:

• set the latency of playbin element, if possible. (This element correctly shows the video)
• Show the video with the correct pipeline since rtspsrc allows me to set the latency.

I use Xubuntu 16.04, gstreamer-tools-1.0 (used 0.10 as well) and the video I stream with VLC has mp4 extension.

Answer 1

you can adjust the latency by setting the right property and using playbin component:

gst-launch-1.0 -v playbin uri=rtsp://localhost:8554/test uridecodebin0::source::latency=300

Hope you find this useful :)

Answer 2

Assume the rtsp stream is h264 format, use explicit h264 decoder and encoder to parse the stream. Use videoconvert and videoscale to change the frame shape.

gst-launch-1.0 rtspsrc location=rtsp://localhost:8554/test latency=100 ! queue ! rtph264depay ! h264parse ! avdec_h264 ! videoconvert ! videoscale ! video/x-raw,width=640,height=480 ! autovideosink

Answer 3

playbin does have a latency option last time I have checked. Note that its scale is different from the one of rtspsrc. rtspsrc is in milliseconds while playbin is in nanoseconds. It may still not go below a certain threshold - depending on the input video requirements (vbv buffer limitations).

For your rtspsrc pipeline you probably miss a videoconvert or autovideosonvert element right before the autovideosink.

Answer 4

I've been trying to get this work and was successful on a raspberry pi 3 so I thought "Well since that was so easy I'll try it on the rpi4" Followed the same steps to get gstream installed but when running the command:

gst-launch-1.0 rtspsrc location=rtsp://localhost:8554/test latency=100 ! queue ! rtph264depay ! h264parse ! avdec_h264 ! videoconvert ! videoscale ! video/x-raw,width=640,height=480 ! autovideosink

It looks like a thermal camera. Still works on the rpi3 just fine though. Not sure what would be making the difference here.

Answer 5

In my case I was receiving a video stream with impressive latency from an android smartphone(server) to an nvidia jetson nano(client) for later inference processing and the following string worked:

pipeline = "rtspsrc location=rtsp://admin:[email protected]:xxxx latency=0 ! queue ! rtph264depay ! h264parse ! avdec_h264 ! videoconvert ! videoscale ! video/x-raw,width=640,height=480 ! appsink"

After replacing the "omxh264dec" decoder with "avdec_h264" in the pipeline they disappeared the following deprecations:

(

python3:10659): GStreamer-CRITICAL **: 22:47:22.966: gst_caps_is_empty: assertion 'GST_IS_CAPS (caps)' failed

(python3:10659): GStreamer-CRITICAL **: 22:47:22.966: gst_caps_truncate: assertion 'GST_IS_CAPS (caps)' failed

(python3:10659): GStreamer-CRITICAL **: 22:47:22.966: gst_caps_fixate: assertion 'GST_IS_CAPS (caps)' failed

(python3:10659): GStreamer-CRITICAL **: 22:47:22.966: gst_caps_get_structure: assertion 'GST_IS_CAPS (caps)' failed

(python3:10659): GStreamer-CRITICAL **: 22:47:22.966: gst_structure_get_string: assertion 'structure != NULL' failed

(python3:10659): GStreamer-CRITICAL **: 22:47:22.966: gst_mini_object_unref: assertion 'mini_object != NULL' failed

I hope i was helpful