MPEG-TS stream shaping problem: please help

[STod]

Hi to all!

I need to stream video from a capture device. The original video is 1920x1080, and the image isn't very "dynamic", so my needs are:
- 10 fps
- no audio
- h264 encoding
- no B-frames
- one I-frame every 5 secs. (I have to record the stream, and this setting helps the seek...)
- no peak when the I-frames are streamed

Therefore when I set VLC I use the following settings:

MRL:

Code: Select all

v4l2:///dev/video0

Input options:

Code: Select all

:v4l2-aspect-ratio=16\:9 :v4l2-audio-input=-1 :v4l2-width=1920 :v4l2-height=1080 :live-caching=1000

sout string:

Code: Select all

:sout=#transcode{venc=x264{keyint=50,qp=0,bframes=0,b-bias=-100,bpyramid=none,ref=1},vcodec=h264,fps=10,vb=0,scale=0,acodec=none}:rtp{dst=192.168.0.150,port=50040,mux=ts{shaping=6000,use-key-frames}}

All seems work correctly, the video is showed on the destination workstation (received with VLC), but if I capture the stream with Wireshark I see a burst of packets every 5 secs, and no traffic in the meantime. This is exactly the opposite of what is described in the "VLC command-line help" about the "--sout-ts-shaping" and "--sout-ts-use-key-frames" options...

You can find a pcap file here:
https://drive.google.com/drive/folders/ ... sp=sharing

With the same sout string, but without "shaping" and "use-key-frames" options, I obtain a "smooth" stream, with peaks every 5 secs (the I-frames) and several packets in the meantime.


What is wrong in the settings I'm using?

I'm using "VLC 2.2.2 Weatherwax" on an "Ubuntu server 16.04" pc (with Lubuntu desktop).
The same settings works ok on a Windows 7 pc with "VLC 2.0.0 Twoflower".


Thanks a lot in advance for the answers!!

[STod]

No answers?

If my question isn't clear enough, or further informations are needed, please let me know.

Thanks!!

[Rémi Denis-Courmont]

This is a very specific question that would need somebody to investigate. And that's just not likely to happen on a free support forum... Consider getting a consultant or investigating yourself.

[STod]

Thank you for your reply!
I will consider to get a consultant...

However I thought that knowing how to correctly use two VLC's parameters ("shaping" and "use-key-frames"), and what should be the VLC behavior when using them, were of general interest.
Unless I'm the only VLC user to use these parameters ....

[HiZ]

I too see the same 5 second behaviour. Wireshark shows the bursts proceeded by an RTCP packet.

Without shaping there are bursts so was hoping this command would improve things rather than make it worse.

Did you make any further progress?