Concepts:
Bitrate refers to the amount of data being sent in your stream. We usually measure bitrate in Kbps (Kilobits per second) or Mbps (Megabits per second).
Resolution refers to the size of a video stream, measured in pixels.
426 x 240 pixels — Also known as 240p, recommended bitrate = 500 Kbps
640 x 360 — AKA 360p, recommended bitrate = 1 Mbps
854 x 480 — 480p, recommended bitrate = 3 Mbps
1280 x 720 — 720p, recommended bitrate = 5 Mbps
1920 x 1080 — 1080p, recommended bitrate = 8 Mbps
3840 x 2160 — 4K, recommended bitrate = 25 Mbps (rarely used for live streaming)
Multi-bitrate streaming is almost always the correct choice for broadcasters. However, keep in mind that it’s more demanding in multiple ways. It takes more data, greater internet bandwidth, and more processing power. Generally, most modern internet connections and computers can deal with this. In most cases, the benefits outweigh the downsides.
Video codec should be H.264. Sometimes H.264 is labeled x264, which is simply an open-source implementation of the encoder. Most platforms and users can’t yet support the next evolution of the H.264 codec.
Audio codec should be AAC. This is the best audio codec for every broadcast. While it may sound less familiar than MP3 to some users, it provides better audio quality at lower bitrates.
Audio sample rate should be set to 44100 Khz. This setting is well-supported, provides excellent quality, and is standard across most audio equipment and recording.
Audio bitrate should match the video resolution. For 360p video or lower, use 64 Kbps mono. For 480p and 720p video, use 128 Kbps stereo. For 1080p and above, use 256 Kbps stereo.
Keyframe interval should be 2 seconds. Other numbers here can cause issues with seeking and other quality problems.
Total required bandwidth = (The sum of all your video bitrates) + (The sum of all your audio bitrates).
In practice, say you’re streaming at three bitrates:
- 426 x 240 pixels — Also known as 240p, recommended bitrate = 500 Kbps (audio bitrate = 64 Kbps)
- 854 x 480 — 480p, recommended bitrate = 3 Mbps (audio bitrate = 128 Kbps)
- 1280 x 720 — 720p, recommended bitrate = 5 Mbps (audio bitrate = 128 Kbps)
In this example, your total video bitrate is 8.5 Mbps (500 Kbps + 3 Mbps + 5 Mbps). Your total audio bitrate is 320 Kbps (128 Kbps + 128 Kbps + 64 Kbps). Adding these two numbers together means your total bitrate is 8.82 Mbps. You’ll want an upload speed that is roughly double this—around 18 Mbps—to ensure a quality stream.
References:
https://www.dacast.com/blog/best-encoding-software-settings/
Streaming Live from Remote Locations with Teradek Sharelink:
https://www.dacast.com/blog/streaming-live-remote/
LiveU Broadcast solutions:
https://www.liveu.tv/
