Question / Help CBR faster than VBR?

[jincuteguy]

Is using CBR a bit faster than compare to VBR? I had frame drops when I used VBR 1080p @ 60 fps, but when I do CBR (with everything unchanged i.e same bitrate and everything), I didn't have a single frame drop. So any infos on this is appreciated.

 

[dodgepong]

It's not about one being "faster" than another. CBR keeps bit rate more constant, while VBR makes bit rate vary more. You were getting frame drops because VBR was using more bandwidth than your connection could handle.

Though streaming at 1080p60 is usually a bad idea no matter what the bit rate...

 

[jincuteguy]

I was only streaming at half of my upload bandwidth (50%), I don't get how I didnt have enough bandwidth when i was using only 50% of it. I was also looking at the bitrate in OBS during the streaming, and it didnt really go over the bitrate that I set it to. So I still don't know how I got frame drops.

 

[dodgepong]

The speed at which you can stream isn't necessarily bound by your quoted upload speed. Your upload speed can be limited by a lot of things. The fact of the matter is that frame drops are caused by insufficient bandwidth to the streaming server, so if your bit rate gets too high, you'll drop frames. CBR is not only required by Twitch, but it's an excellent way to keep bit rate from getting too high or low.

 

[Krazy]

Expanding a bit on what dodgepong said, it's not just about how much bitrate you can sustain, it's more about what the entire connection between yourself and the Twitch server can sustain. Generally there are about a dozen different nodes your data goes through before it actually gets to the Twitch server, and if any one of those "hops" as they are called are overloaded or faulty (including the Twitch server or your connection) then you could experience network congestion. It's not as simple as "I have 25Mbps upload, so I surely can always stream at 3Mbps!"

 

[jincuteguy]

Yea I understand that it is also depend on the route between me and the twitch server. So it 's prob the server is having issue.

 

[Momentum]

What i have noticed is, i set bitrate to 1000 CBR, but when i stream, it constantly shows around 1150 bitrate, sometimes goes to 1200. Is this normal behaviour? If its worth mentioning, my audio is 48kbps AAC

 

[dodgepong]

It's normal for the displayed bit rate to fluctuate up and down from what you set your bit rate to.

 

[Krazy]

Also, there's a problem with the AAC encoder and it won't actually go lower than 128Kbps, no matter what you set it to.