The Effects of Uplink Speed on Video Quality

[Sinc747]

How important is the uplink speed for quality video?

For those of us that are uplink-challenged, having to stream in 300-400k bps limits what we can do. But, how much difference does speed really make?

Let's look at three scenarios (based on my Core2Duo rig).

First
Slow uplink (300). VB/FMLE stream quality set at 296k bps (Stereo sound of 96k bps steals 48k bps vs. mono). Video resolution set to 320x240. Frame rate is 30 fps. Output in Program module is of fair quality (not great or good, but fair). - This is my typical set up.

Second
Fast uplink (1,000). VB/FMLE stream quality set at 528k bps (Stereo sound of 128K stealing 64K vs. mono). Video resolution set at 320x240. Frame rate is 30 fps. What will the output (Program module) look like? Better? Same? A lot better?

Third
Super fast uplinlk (2,000+). VB/FMLE stream quality set at 1128k bps (Who cares about stereo vs. mono, lots of uplink to spare). Video resolution set at 320x240. Frame rate is 30 fps. What will the output (Program module) look like? As good as the 320x240 DV from the cameras?

Notes
- It would be nice to have some intermediate stream quality settings: 700, 850, etc. to match whatever speed is available.
- It would be nice to concerve what little speed there is by having a mono option.

[wiav8r]

Tom,
Are you asking if "Program" output on VB will improve if you up-link speed changes? Or are you referring to "program' on you CDN?

Up-link speed wont effect VB Program will it? That is matter for CPU, video capture right Mike?

[Sinc747]

Allan,

"Are you asking if "Program" output on VB will improve if you up-link speed changes?" No. Sorry for the confusion.

"Or are you referring to "program' on your CDN?" Yes.

The way I understand FMLE is that you can set the encoder bit rate, and the higher the bit rate, the better quality the video stream. But the bit rate can't exceed the upload speed or you'll end up with a FMLE buffer that fills/overflows, and then you lose frames or quality degrades.

I know that my 320x240 VB/FMLE output (to Ustream, in my case) does not have near the quality and fine detail of my 320x240 camera input into VB. But, my bite rate is less than 300 due to upload limits.

My understanding is that the way up-link speed affects VB is that you can't allow VB/FMLE to encode faster than you can stream.

Am I way off base?