The VideoLAN Forums

Posted: **18 Jun 2011 13:35**

Hi everybody!

I'm trying to implement a Multicast Stream (mainly videos but also music) on a local arey network. Latest VLC version on Ubuntu machines.
Since it's a very confusing thing when your clients are not synchronized, im asking you which is the best way to "force" it to be always synchronized?

I tryied using the network synchronisatoin feature.

using cvlc --network-synchronisation --netsync-master [..] on server
vlc --netsync-master-ip "hostip" rtsp://[..] on clients.

But it seems to have simply no effect. As long as there is no connection issue streams keep on very high synchronisation (~20ms dely, unoticable, half on a frame) but if i encounter some trouble, like unplugging a cable and stuff. The synchronisation is lost, with or without network synchronisation. All reports about this feature i found, were about v0.8.6.

However --clock-jitter 0 works fine to me (without netsync-master) , i can't force a desync via unplugging cables. How ever i haven't tested this configuration via WLAN so far and i expecting some issue there, with --clock-jitter 0.

Any ideads how to make the --network-synchronisation work? All ideas to get a rockstable multicast stream are welcome, too!

Also i want which is the best container/encoding format to stream on low latency, pls add a reasonable explanation why this container/encoding is the best ("FLASH is used everywhere" is no reason to me

).

Thanks in advance!

Hardt

Posted: **01 Jul 2011 15:29**

Hi,

Im still working on this

Well I'm experiencing trouble streaming 720p Movies to the Intel Atom CPU based Clients, the movie works fine if i play it on the local PC (50% CPU consumption).
While streaming i get multiple errors resulting in artefacts, the worst point is, the errors are reproduceable, same errors at the same playbacktime (While streaming).

Code: Select all

[0xb4b0118c] main input error: ES_OUT_SET_(GROUP_)PCR  is called too late (pts_delay increased to 1200 ms)
[0xb4b0118c] main input debug: ES_OUT_RESET_PCR called
[0x9982c1c] xcb_window window debug: key: 0x00000066
[0x996b714] main generic debug: VoutDisplayEvent 'resize' 1024x768 fullscreen
[0x996b714] main generic debug: VoutDisplayEvent 'resize' 1024x768 fullscreen
[0x99228b4] ts demux warning: discontinuity received 0x1 instead of 0x9 (pid=68)
warning: first frame is no keyframe
[0xb4b0118c] main input debug: Buffering 0%
[0xb4b0118c] main input debug: Buffering 5%
1. marker bit missing in 3. esc
Error at MB: 2688
[0xb4b0118c] main input debug: Buffering 11%
libdvbpsi error (PSI decoder): TS discontinuity (received 2, expected 11) for PID 0
[0x99228b4] ts demux debug: PATCallBack called
libdvbpsi error (PSI decoder): TS discontinuity (received 2, expected 11) for PID 66
[0x99228b4] ts demux debug: PMTCallBack called
[0xb4b0118c] main input debug: Buffering 17%
[0xb4b0118c] main input debug: Buffering 23%

Maybe it depends on my configuration?

My reference Video is Elephants Dream 1280x720 http://video.blendertestbuilds.de/downl ... D_1280.avi

Server configuration:

new chanel1 broadcast enabled loop
setup chanel1 input Open Source Film/ED_1280.avi
setup chanel1 output '#rtp{mux=ts, dst=239.1.1.1, port=20010, sdp=rtsp://10.0.0.1:8080/chanel1.sdp}'

Client(s) configuration:

cvlc -vv --loop rtsp://10.0.0.1:8080/chanel1.sdp

The best idea is to use a slightly lower quality (1024x576 works fine) but it is part of my Bachelor Thesis and i need to do some investigation here.

Also i wonder about the rtp{mus=ts... without this Option most videos won't play comfortable, but i thought Transport Stream was about MPEG2, this option seem to have a (positive) effect on mpeg4 vids like Elephants Dream to.

Looking forward to some feedback

greetings Hardt

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