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Sub Second Streaming

Enjoy sub second latency streams with our new streams!

Khandoker Zishan avatar
Written by Khandoker Zishan
Updated today

Sub-Second Streaming represents a significant advancement beyond our Ultra Low Latency (ULL) technology. Unlike the ULL player, which faced limitations in mobile device compatibility, Sub-Second Streaming is designed to operate seamlessly across mobile platforms.

  1. How to create a Sub Second Stream

  2. Recommended encoder settings

  3. How to Customize the Stream Offline Message

  4. Important Notes

How to create a Sub Second Stream

To create a Sub Second Stream, open the menu and click on create.

Name your stream and select a region that is closest to you.

Copy the RTMP URL and Key from here and paste it on your encoder.

Once the stream starts, open the player from here to enjoy the stream.

Note: To enjoy audio only stream, open the player from the Audio tab.

Recommended encoder settings

To ensure that your stream is stable we recommend the following:

  • Bitrate: 2000 kbps

  • Keyframe Interval: 2 seconds & Keyframe aligned

  • Rate Control: Constant Bit Rate (CBR)

  • Tune: Zero Latency

  • Profile: Baseline

How to customize the stream offline message

You can display a custom message when the stream is offline by adding a parameter to your stream URL.

Steps:

  1. Modify the Stream URL
    Append ?offlineText=your_custom_message to the URL. Use %20 instead of spaces.
    ​Example:

    https://player.castr.com/ss_abc?offlineText=Stream%20is%20currently%20offline

  2. Automatic Encoding in Modern Browsers
    Most modern browsers will automatically encode your message.

  3. Manual Encoding (if needed)
    Use this tool to encode messages manually:
    ​https://www.urlencoder.org/

Important Notes

  • Viewer Limit: By default, Sub-Second Streams support 5 concurrent viewers and include a watermark. To upgrade, please contact Sales.

  • Plan Access: Only available for users on the Premium plan or higher.

  • Autoplay Policy: To force autoplay with audio where supported, add ?autoplayPolicy=true to the player URL.

  • Viewer Cap: If your plan includes a 50-viewer limit, the 51st viewer will see an error message.

  • Player Requirement: Sub-Second latency works only via Castr's player. Streaming to social platforms will use standard latency.

  • Audio Limitation: Only a single audio track is supported.

Hope to see how you use our Sub Second Streams can let your viewers enjoy streams in real-time!

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