Streaming video and bandwidth

[MoparShaha]

I've set up a streaming video system for an organization, but I'm not sure what level of compression to use for the video. Sadly, they use Windows, so I'm using WMP Encoder, but that's irrelevant to my question. They are using a DSL line that has 768Kb/s upload speed, which is pretty good. At most, I expect 30 users to be accessing the stream, and thats like once a year maybe. Usually there might be a few people watching it. So, my question in a nutshell, is what level of compression should I use for the video so it won't exceed the upload bandwidth. I'm currently compressing the video at 180 Kb/s, and it's at an acceptable video quality. I just don't know how the video compression and upload speed correlate. I think there's more to it than dividing the upload bandwidth by the compression level to figure out how many users we can accomodate. Anyone have any experience with this?

 

[Rower_CPU]

I've got an Excel spreadsheet at work that calculates this for you that I'll try to post tomorrow.

You can definitely ballpark it though and at 180 Kb/s you're only going to get about 4 connections at a time before they start fighting each other for bandwidth.

 

[MoparShaha]

Originally posted by Rower_CPU
I've got an Excel spreadsheet at work that calculates this for you that I'll try to post tomorrow.

You can definitely ballpark it though and at 180 Kb/s you're only going to get about 4 connections at a time before they start fighting each other for bandwidth.

Thanks for the response. So it is as easy as dividing the bandwidth by the compression to get total numbers of users?

Also, I don't know if Windows Media Encoder does this, but would it dynamically increase compression to compensate for an additional load of users? Do other streaming programs like Quicktime Broadcaster do this?

 

[Rower_CPU]

I'm not familiar enough with Windows Media Encoder to say if it does or not, but from what I've seen, QT Broadcaster won't dynamically adjust the compression.

 

[MoparShaha]

Thank you very much Rower_CPU, you've been a great help. Looks like we're going to need more bandwidth or more compression. Probably more compression, T1 lines are expensive .

 

[Rower_CPU]

OK, I found the spreadsheet. It only goes down to T1, but you can extrapolate the numbers.

 

[MoparShaha]

Thank you for the spreadsheet, very cool.

 

[Nermal]

I think only RealServer can automatically adjust the bandwidth (they call it SureStream). Personally, I think that the RealNetworks streaming suite is the best out of the 3 main providers. Microsoft Media Services (Windows Media) is horrible, the MMS protocol isn't even capable of doing 100% accurate transfers. Now, if only there was a way to convert RealVideo files into some "normal" format.