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Required RTMP streaming encoder settings

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When streaming to RingCentral Events via RTMP, it's crucial to ensure your configuration meets our requirements. This guide covers the necessary encoder and network settings for optimal performance.

Resolution/Bitrate/FPS settings

Bitrate, frame rate (frames-per-second, or FPS), and resolution are interrelated. Start with the values recommended below and adjust as needed to find the best configuration for your software. Increasing frame rate and/or resolution increases overall streaming quality, but you should always consider your encoder and network bandwidth limitations.

  Acceptable Quality (SD) 480p (852x480) Good Quality (HD) 720p (1280x720) High Quality (Full HD) 1080p (1920x1080)
Average Bitrate Up to 1500 Kbps Up to 4500 Kbps
(3000 Kbps recommended)		 Up to 8500 Kbps
(5000 Kbps recommended)
FPS 30 30 30
Keyframe interval 2 seconds 2 seconds 2 seconds

Note:

  • Resolution: The resolutions listed are for landscape orientation (horizontal x vertical). Reverse the values for portrait orientation.
  • Quality limits: We currently do not support 4K streams. Streams over 1080p or bitrates over 8500 Kbps will be rejected and will not stream properly. A bitrate of 5000 Kbps generally works well in most situations.
  • Bitrate: The bitrates listed include both video and audio streams. Do not set the video bitrate to 8500 Kbps with an additional audio bitrate of 192 Kbps. Ensure the total bitrate does not exceed 8500 Kbps. This is a strict upper limit, and if your total bitrate fluctuates slightly above this, you will be disconnected. We recommend setting the bitrate to 8000 Kbps to account for any network spikes or fluctuations.

Audio settings

  • Codec: AAC (LC)
  • Bitrate: Anything up to 320Kbps
  • Sample rate: 44.1 kHz or 48 kHz (best to match your production audio flow)
  • Channels: Maximum 2 - Stereo (1: mono or 2: stereo audio channel support)

Video settings 

The following settings should be strictly adhered to. They are available in most H.264 video-encoding software or hardware APIs.

  • IDR/Keyframe: 2-second interval (or 1 second, for even lower end-to-end latency)
  • H.264 level: Main (not High)
  • Scene change: Off 
  • Chroma subsample: YUV420P
  • CABAC: Preferred
Tip: Once you have applied the video and audio settings and determined the quality level (Acceptable, Good, or High) you want to stream, stream a test feed to the stage for at least an hour. Monitor the stream by previewing the event. Additionally, review the recordings after your test. If you notice multiple recordings for one stream, it means the stream was interrupted and you may have incorrect encoding settings.

Using CBR, not VBR

Always use CBR (Constant BitRate) instead of VBR (Variable BitRate) as the rate-control method for encoders. CBR is better suited for the fixed-bandwidth nature of networks and produces more predictable, stable video playback for client devices. With a consistent bitrate, viewers can select a quality level that their connection can handle over time.

VBR can cause bitrate spikes, leading to frame drops and buffering issues in client players. Any streaming bitrate above 8500Kbps will be rejected, causing your encoder to disconnect and interrupt the stream for viewers.

Using progressive signals

Use progressive signal flows and avoid interlaced video in production and encoding. Progressive stream signals yield better playback quality by displaying a whole frame at a time, avoiding motion artefacts produced by interlaced signals.

Network requirements

  • Stable connection: Use an internet connection that can maintain an adequate, constant upload stream. An unstable internet connection could result in stream stuttering and lagging for your viewers.
  • Wired connection: WiFi and LTE connections can be spotty or suffer from interference or latency due to bad QoS/packet-queue prioritization. Whenever possible, rely on a hardwired connection for streams.
  • Higher bandwidth: Allocate 50% more bandwidth than the minimum required. The overhead is added to compensate for the bitrate fluctuations in the encoding of a video bitstream.
  • Isolated infrastructure: Use a dedicated Internet VLAN to encode machines. Keeping the encoder on a separate network prevents potentially disruptive effects (pollution by traffic, bandwidth bottlenecks and adverse security factors).
  • Open ports: Your video encoder must connect to RingCentral Events over the RTMPS protocol associated with outbound port 443/TCP. Refer to our guide on Network Connectivity Settings to learn more about network ports and URL whitelisting (especially when using a corporate network behind a firewall, VPN, or proxy server). 
Tip: For more details and recommendations, refer to the support pages of our preferred provider MUX and the fallback provider Amazon IVS. 

Tip: If your streaming software supports multi-streaming, we recommend sending your stream to both the primary and backup servers simultaneously. This ensures an automatic and seamless transition to the backup if any issues occur with the primary stream, maintaining a smooth experience for your attendees. To learn more about technical recommendations and requirements, refer to our guide Streaming to both preferred and backup/fallback RTMP endpoints.

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