Posted: September 08 2004 at 1:18pm | IP Logged

Our problem is that the streaming output of the card fluctuates greatly after 2 min of webcasting. 

We have an Osprey 230 card in a Shuttle XPC (Intel 865G chipset) box with a P-4 2.x ghz and a gig of ram running Win2K.  The box was custom built just to handle our streaming needs. 

Our networks tests show that when the card was set to output at 350Kbps, the fluctuation was +/- 30K. When the card was set to 450Kbps, the fluctuation was +/- 120K.  We are connecting through a dedicated T-1 directly from UUNet.  This is the only computer sending/receiving on the network. 

Is there some technical issue that would cause the Osprey 230's output to fluctuate so much? Why would it, in each instance, drop to "just below 350" before recovering? 

When the output drops below 350Kbps, our webcast is terminated (we are directing the output to our own servers which monitor the incoming stream - and then terminates it when the signal drops below 350Kbps).  We MUST maintain 350Kbps or higher for our applications/products to work (long explanation, just trust me on that).

Our setup varies, the following are typical:

1. Canon XL1S s-video output connected directly to the Osprey 230 S-video input. Audio Technica lav mics connected to the XLR L/R inputs.

2. Camera and other video/audio sources (dvd player, etc.) connected to a Videonics MX PRO mixer, with output (s-video and audio-rca l/r) connected to the Osprey 230 s-video input and XLR L/R inputs.

Any suggestions, tips, tricks, etc. you can provide would be greatly appreciated. 

Posted: September 15 2004 at 2:38pm | IP Logged

Hi, you don't mention whether you are encoding a Windows MBR (multi bit rate) file or a Real SureStream file but if this is the case then what you are experiencing is the expected result.

When MBR or SureStream is used then the Player negotiates for the highest possible bandwidth in the stream.  Should the network become congested and less bandwidth becomes availble, it may "fluctuate" down until it is able to negotiate for a higher stream again. 

My recommendation is to encode a CBR or Single rate stream at the optimum bitrate desired.  For additional bitrates, use a 2nd card or SimulStream for the Osprey, to encode additional streams at the desired bitrates.

Posted: September 17 2004 at 12:43pm | IP Logged

Thanks for the response. 

It is Windows MBR that we're using.

MORE INFO:

When the computer is connected to a single T-1 line (1.5mbs), it streams fine with little or no fluctuation in the outgoing stream.

When the computer is connected to a Bundled T-1 line (3 T-1's ~ 4.5mbs), we experience significant fluctuation in the outgoing stream.

Do you have any idea why the fluctuation would occur on the bundled T-1's (which effectively provide greater dedicated bandwidth)?

Would setting the device to use CBR fix this problem?

Thanks,

Webitt