"Keyframes, CBR and encoders: why your stream stutters"

Updated 2026-10-19 · 404 words

Streaming software has dozens of settings, but a handful cause almost every "my stream looks bad" complaint. Here's what they do and where to start.

Rate control: use CBR

Constant bitrate (CBR) sends a steady amount of data every second. Variable bitrate (VBR) spends more on busy scenes and less on calm ones. VBR is great for recordings, but live platforms and viewers' connections cope best with a steady stream, so most platforms recommend CBR for live. Set the bitrate from the calculator.

Keyframe interval: 2 seconds

Video is compressed by sending a full picture (a keyframe) now and then, and only the changes in between. Platforms need keyframes at regular intervals to start viewers' playback and to switch qualities. 2 seconds is the setting most platforms ask for. "0" or "auto" can produce irregular keyframes, which can cause buffering or a stream that won't start for some viewers.

Encoder: hardware first

• Hardware encoders (NVIDIA NVENC, AMD AMF, Intel Quick Sync, Apple VideoToolbox) use a dedicated part of the graphics chip. They barely touch game performance, and on recent cards the quality is very good.
• x264 (software) runs on the CPU. At slower presets it can look excellent, but it competes with your game for CPU time and can make both stutter.

If you're streaming and gaming on one PC, start with the hardware encoder.

Preset and profile

Presets trade quality against processing time. If your encoder warns that it's "overloaded", choose a faster preset or lower the output resolution. Leave the profile at "high" unless the platform says otherwise.

Three different kinds of stutter

It helps to know which one you have:

1. Dropped frames (network). The software can't send data fast enough. Fix: lower bitrate, use a cable, stop background uploads.
2. Skipped frames (encoding). The encoder can't keep up. Fix: hardware encoder, faster preset, lower resolution.
3. Lagged frames (rendering). The PC can't draw the scene fast enough, usually because the game is using all the GPU. Fix: cap the game's frame rate, lower game settings, simplify scenes.

OBS and most streaming apps show these counters separately in their stats window. Read them before changing anything.

A safe starting set

Change one thing at a time, run a short test stream, and check the counters.