Question / Help Please explain "custom buffer size"

[Videophile]

Hey guys,

I was experimenting around with custom buffer sizes. I stream BF4 from my PC at 1080p downscaled to 720p30. I stream using 3500 kbps, but for shits-n-gigs I tried a 4000kbps buffer. The quality was a lot better. Can anyone explain in what exactly the buffer does VS the stream bit rate?

Thanks a bunch,

-Shrimp

 

[Boildown]

Was hoping to find a good explanation here: http://mewiki.project357.com/wiki/X264_ ... V_Encoding

But I'm kind of left wanting after reading that. I'm pretty sure it had to do with how much extra bits the stream can utilize in a given period of time to make up for highly complex scenes that would otherwise look bad. The downside is that by using extra bits, it spikes your connection on the upload, and every viewer's connection on the download. If you're partnered it probably doesn't matter because Twitch will smooth it out on the re-encode (assuming spiking your upload doesn't lag your game). If you're not partnered, its probably a bad idea to ever have your buffer greater than your bitrate (rule of thumb).

I only get 5Mb up (tests to 4.6 at testmy) and if I try to do 3000/3000, my gameplay suffers. So I do 3000/2000. I stream 720p60 (Planetside 2, FPS) and I think the quality is pretty good.

 

[Videophile]

I think you might be right.

I read that same article, but it wasnt well explained.

Thanks anyways!

-Shrimp

 

[dodgepong]

Sigh...VBV buffer is extremely complicated to describe...one of these days, I should write my own writeup of how it works, because I've never read a decent explanation of it.

 

[Krazy]

This is the only decent info I've ever found on how it actually works, but it takes some sorting through as it's an IRC log:

https://trac.handbrake.fr/wiki/VBVRateControl

 

[Boildown]

That was an interesting read. The only semi-important question I still have is whether a large buffer changes the low-end of the bitrate variability. For example, if you do a bitrate of 3500 and buffer of only 1000, will that mean that the bitrate stays closer to 3500 during static very-little-bitrate-needed scenes, compared to a bitrate/buffer of 3500/3500, which may be free to lower the bitrate to close to 0?