question about raspberry camera video straming with gstreamer

Fri May 8 17:05:16 UTC 2020

Dear Sebastian,

thanks for your responses.. I hope you are enjoying your time here
especially now that it is like summer..
I'm just trying to accomplish a video streaming between raspberry camera
and a computer without much latency and without having dropped frames and
pixelated images.. The video streaming will be between a drone (raspberry
is on the drone) and a computer so i need a clean image without a lot of
latency..

I'm not familiar with gstreamer at all.. I have no programming experience..
So its more difficult for me to achieve my goal.. I just search  over the
internet and try several commands other people have used so far until i
find one that works adequately..

So after searching i found the github page of a guy named Jan Schmidt which
as far as i understood he works for gstreamer.. And raspicamsrc that you
proposed, can be found on his github page and i have already installed it..
That guy Jan, after he saw how i am currently streaming video (same
commands that i told you in my previous email) ,he proposed me to use the
SRT protocol. Yesterday he replied to me saying:

Without some kind of retransmission, packet loss will always cause trouble
> like that. You need to switch away from a raw RTP stream, really.
> If you have a recent enough GStreamer available, look at using the SRT
> protocol for streaming instead.

So yesterday i searched how i can do video streaming with raspberry camera
using gstreamer with SRT protocol.. And luckily i found a guy in github
that has already done exactly what i want to do.. His page
https://github.com/PietroAvolio/Building-Gstreamer-Raspberry-Pi-With-SRT-Support

So i followed his instructions which are quite straightforward even for
novice users and i was almost sure that finally i will make things work. He
actually says to install SRT from the SRT github page, then execute a
script that installs several Gstreamer things and then install the
RPICAMSRC element. After doing all these, once i give in raspberry the
command:

gst-launch-1.0 -v rpicamsrc preview=true sensor-mode=5
bitrate=8000000!
video/x-h264,width=1640,height=922,framerate=40/1,profile=baseline !
mpegtsmux ! srtsink uri=srt://:8888

I get the error   *WARNING: erroneous pipeline: no element "srtsink"*

As far as I understood i am close to make it run, I just feel that the
Gstreamer cannot see the srtsink plugin , although I followed the
instructions to install SRT. I guess Gstreamer is looking for srtsink in
different locations than where SRT is actually installed. When i run
*gst-inspect-1.0
srt * , i get no results.. When i run  * gst-inspect-1.0 x264*   i get
results for this plugin and for several other plugins i tried.

DO you know how can i fix this  ??  Probably its something easy and i just
dont know how to fix it.. How to make  Gstreamer see the srt  plugin..

Unfortunately , i cannot contact that guy that wrote this process with
Raspberry camera, srt and gstreamer.. I cannot find his email..

I would really appreaciate if you could propose any fix for this .. Thanks
a lot

Best Regards,

On Fri, May 8, 2020 at 12:05 PM Sebastian Dröge <sebastian at centricular.com>
wrote:

> On Thu, 2020-05-07 at 22:13 +0300, apostolis paraschoudis wrote:
> > Hello,
> >
> > Unfortunately I am not an advanced user with raspberries , Gstreamer
> > and networks and I couldn't find a solution to my problem in several
> > forums (i couldn't find any dedicated forum for Gstreamer ! ) .
> > I am trying to transmit video from my rapsberry camera (connected to
> > RPI 3 B+) to my windows laptop through gstreamer.
> >
> > In my laptop i give the command :
> > gst-launch-1.0.exe -v udpsrc port=5600 caps=“application/x-rtp,
> > media=(string)video, clock-rate=(int)90000, encoding-
> > name=(string)H264” ! rtph264depay ! avdec_h264 ! videoconvert !
> > autovideosink sync=f
> >
> > and on my raspberry the command:
> > raspivid -n -w 1280 -h 720 -b 1000000 -fps 15 -t 0 -o - | gst-launch-
> > 1.0 -v fdsrc ! h264parse ! rtph264pay config-interval=10 pt=96 !
> > udpsink host=xxx.xxx.xxx.xxx port=5600
>
> There are two things to improve here, on both sides.
>
> For the receiver, can you add an `rtpjitterbuffer` element between the
> `udpsrc` and the `rtph264depay`? That would allow for some buffering,
> fix up packet reordering and create more useful timestamps, among other
> things.
>
> On the sender side I would recommend using the `rpicamsrc` element from
>   https://github.com/thaytan/gst-rpicamsrc
> instead of piping the `raspivid` output to `gst-launch-1.0`. That's
> going to work more robust and reliable, and also provide better
> timestamp and other metadata to GStreamer.
>
> Once changing that it should work better, maybe already well enough.
>
> --
> Sebastian Dröge, Centricular Ltd · https://www.centricular.com
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
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