Guides
Live streaming bitrate settings: a practical guide
Bitrate is the single setting that most affects how your stream looks. Here are sensible numbers by resolution, and the arithmetic behind them.
By CastNest TeamUpdated 4 min read
What bitrate can and cannot fix
Bitrate is the amount of encoded data sent each second. More bitrate gives the encoder room to preserve detail, but cannot repair an out-of-focus camera or distorted audio. A clean 720p picture can be more useful than blocky 1080p on an unstable connection.
The right setting depends on resolution, frame rate, codec, scene complexity and destination requirements. A speaker against a plain background needs less data than a moving crowd. Test your most demanding scene in the player your audience will use.
H.264 starting ranges for rehearsal
These are practical starting ranges, not published limits for every platform. They describe video bitrate only; audio and transport overhead are additional. Your destination may recommend a different range, so its current requirements take precedence. Start presentations at 30 fps and use 60 fps when movement justifies the extra data.
- 720p30: test 2,500-4,000 kbps.
- 720p60: test 3,500-5,000 kbps.
- 1080p30: test 4,500-6,000 kbps.
- 1080p60: test 6,000-9,000 kbps where accepted.
- AAC stereo audio: test 128-192 kbps where supported.
Calculate upload headroom
Add video and audio first. A 6,000 kbps video stream plus 160 kbps audio is 6.16 Mbps before overhead. A planning target of roughly twice that combined rate gives about 12.3 Mbps of sustained available upload. This is a rehearsal target, not a reliability guarantee.
Measure at the venue at a comparable time of day and leave capacity for other users. Cloud multistreaming receives one upload and distributes it onward. Sending several outputs directly from your encoder consumes upload bandwidth for each copy.
Budget viewer delivery separately
Upload capacity and hosting bandwidth measure different parts of the workflow. As a decimal estimate, data in GB equals bitrate in Mbps multiplied by hours multiplied by 0.45. A continuous 6 Mbps feed uses about 2.7 GB per hour before overhead.
If 100 viewers each watch a full hour at 6 Mbps, delivery is about 270 GB before overhead. Actual delivery depends on watch time and the renditions received. Do not budget as though every viewer will receive the lowest quality level.
Set keyframes and rate control deliberately
Use the rate-control mode and keyframe interval required by your ingest service. Constant bitrate is commonly used for live H.264 contribution to keep outgoing load predictable. A demanding quality preset can improve compression but overload the encoder during complex scenes.
If one unchanged feed goes to several platforms, choose a profile accepted by all of them. Cloud replication alone does not change codec, resolution or bitrate. Separate transcoding is needed for outputs with different requirements.
Understand adaptive bitrate
Adaptive playback offers multiple renditions so a player can choose one suited to a viewer. It helps a slow viewer connection, but cannot repair a source already dropping frames before it reaches the service.
Confirm that transcoding is included and enabled. The current CastNest comparison places ABR transcoding from Premium; check included usage and limits. An embedded player does not by itself mean multiple quality levels exist.
Test and keep a stable fallback
Record your settings, broadcast a representative segment and watch on desktop and mobile. If motion looks blocky with a healthy connection, test more bitrate within the allowed range or lower resolution. If upload frames drop, reduce outgoing load and investigate the network.
If the encoder remains healthy but only some viewers buffer, investigate delivery and available renditions. Save the best tested profile as a fallback. A slightly softer picture that stays live is more useful than repeated interruptions at a higher resolution.