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Stream Switching Lags

Posted: 05 Feb 2007 18:47
by rahim_pardhan
I will begin with a bit of background on my project.

I have a server which has 16 instances of VLC open. Each instance is streaming a UDP multicast video. I have multiple clients which open the UDP streams. I am having some difficulty switching between streams on my client.

I have a VLC ActiveX control in my application software and i proceed by adding a stream to the playlist. When I want to switch streams I clear the playlist and then add the new stream. This produced considerable lag (maximum 10 seconds between switching). When the streams were switching the VLC orange pylon came up in my activex control.

Then I thought it would be faster to switch between streams if I loaded all 16 into the playlist. Then I would only have to switch between playlist items instead of re-creating the playlist. However this has proven to be just as slow as the previous method.

My question: is there a way to seamlessly switch streams on the client side without delays (or a way to reduce delays). Basically I do not want to be able to see the VLC logo in my activex control during switching.

If it helps i'm using NI LABView 7.1 as my application development package.

Any help is greatly appreciated

Thanks,

Rahim

Posted: 05 Feb 2007 23:33
by rahim_pardhan
So I just found out something interesting that may help you help me :P

I have 3 instances of VLC streaming a file via UDP multicast on my server. I opened up VLC player on my client and added the 3 UDP addresses to my playlist. I let one stream load and then selected another stream from the playlist. The window with the video closed (only the base VLC player with controls was visible) and there was a delay (about a second or 2) after which the new stream loaded.

Basically I eliminated my software and activex control from the equation and just used VLC to test to see if the issue was still present....and it is.

I should mention that sometimes the video window doesn't close and instantly loads with the new stream. I'd like for this to happen all the time.

Any ideas?

Thanks

Rahim

Posted: 06 Feb 2007 03:56
by DJ
Each time a file starts it loads all the libraries, DirectX and etc. When the file finishes everything is released and the process starts over again. When the formats and container are identical Windows cache memory is used to speed the process. There are no settings to change this action.

Posted: 06 Feb 2007 15:19
by rahim_pardhan
Is there any way, then, to increase the amount of windows cache memory available to VLC? The files are the exact same format/resolution.

Thanks,

Rahim

Posted: 07 Feb 2007 10:08
by DJ
This is NOT the audio and or video cache buffers this is program cache and I have never seen a way to change this action as it would change the way all programs work (load & unload) under Windows. A faster Machine perhaps???

I can split a video file and run the two parts in full screen back to back and never know where the split was. However, some users can't do this.

Posted: 07 Feb 2007 23:08
by rahim_pardhan
Thanks for the tips DJ. I tried opening a different video file and doing the same procedure. Everything works great--switches are instantaneous! Looks like the file I was using to do my testing was causing all the problems.

Thanks for all of your help

Rahim