The Delay in the VLC streaming

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yKevin
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The Delay in the VLC streaming

Postby yKevin » 15 Oct 2008 10:03

Hello, everyone

First, I thank all the people who helped me or paid attention to all my questions. :mrgreen:
Now I'm working on the Streaming with DirectShow part of VLC, I want to talk about the delay in
streaming play. I got a camera in my PC, and I want to capture video in one VLC terminal, but to play the video in another one.
It works well--thanks to ALL the developers of the VLC :mrgreen: , then I test the delay, it's about 1.7s, that's not acceptable, I think.
So I post this message to ask help about the delay in VLC.
In the beginning, I thought it's the network issues the delay, but it's not that long.
And now I focus on the VLC modules, such as buffer allocation, the package parses, etc.
How is your suggestion? You can give me a reply.
ANY information is WELCOMED.

Regards,
yKevin

Jean-Baptiste Kempf
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Re: The Delay in the VLC streaming

Postby Jean-Baptiste Kempf » 15 Oct 2008 10:55

Decrease caching. Use UDP or RTP streaming.
Jean-Baptiste Kempf
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VLC media player developer, VideoLAN President and Sites administrator
If you want an answer to your question, just be specific and precise. Don't use Private Messages.

yKevin
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Re: The Delay in the VLC streaming

Postby yKevin » 15 Oct 2008 11:26

I used UDP streaming.
But I think decrease catching may work, and how can I do that? Need I configure with VLC or modify the source code? :mrgreen:

Thanks
yKevin

yKevin
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Re: The Delay in the VLC streaming

Postby yKevin » 15 Oct 2008 11:45

F.Y.I, I used the 0.8.6e version.
:mrgreen:
Thanks
yKevin

georgesdev
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Re: The Delay in the VLC streaming

Postby georgesdev » 15 Oct 2008 17:06

You should configure the cache on the receiving vlc player.

input/access modules/udp

NB by default it is 300ms, so no big hope of reducing dramatically the delay there

On "server side", you have stream output/access output/udp that is also at 300ms and maybe you can tune it down a bit.

now to get to 1.7 second of delay, there must be something in the transcoding layer that is also caching.
Maybe choosing a smaller GOP size helps (maybe vlc caches a full gop, and that could be a second.
If that can be tuned, it may improve your delay.
Georges

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Re: The Delay in the VLC streaming

Postby georgesdev » 15 Oct 2008 17:12

remember that lowering cache value will have side effects on you video quality ...
1.7 seconds of delay is quite commonly accepted. Although I understand you may want to try to lower his
Georges

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Re: The Delay in the VLC streaming

Postby Jean-Baptiste Kempf » 15 Oct 2008 17:16

No, you can do way better than 1.7 seconds, especially on LAN.
Jean-Baptiste Kempf
http://www.jbkempf.com/ - http://www.jbkempf.com/blog/category/Videolan
VLC media player developer, VideoLAN President and Sites administrator
If you want an answer to your question, just be specific and precise. Don't use Private Messages.

yKevin
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Re: The Delay in the VLC streaming

Postby yKevin » 16 Oct 2008 10:02

Thanks to georgesdev and j-b,
and I think 1.7s is not that acceptable in the project,
so I'll work on decrease catching in the source code of VLC. :mrgreen:

Regards,
yKevin

Jean-Baptiste Kempf
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Re: The Delay in the VLC streaming

Postby Jean-Baptiste Kempf » 16 Oct 2008 11:51

You can decrease your dshow caching to something pretty low in a normal machine.

Mux in TS/udp and set your client caching in UDP a bit lower than usual.
Jean-Baptiste Kempf
http://www.jbkempf.com/ - http://www.jbkempf.com/blog/category/Videolan
VLC media player developer, VideoLAN President and Sites administrator
If you want an answer to your question, just be specific and precise. Don't use Private Messages.


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