What to Do When Your TCP is Out of Order & Green Artifacts Are on Screen

Order packets and green screen artifacts during live streams can pose a problem for broadcasters. In this post, we’re going to discuss how to troubleshoot when your TCP is out-of-order and how you can fix it.

For a universal live stream, you may experience one or both of the following issues:

• the HDS stream displays Jitters
• the HLS stream displays green screen or artifacts

This applies to stream packaging, which is what Dacast uses.

Explanation

This issue occurs when the encoder sends “Out of Order” timestamps. If the encoder is sending a specific number of packets, each of these has a timestamp. This timestamp value should always be increasing. 

If these values are not in order, there can be complications during playback. Media Services Live for Stream Packaging requires FLV timestamp data from the RTMP encoder to be in increasing order regardless of types (audio/video/metadata/etc.)

Note: Keep in mind that Adobe’s RTMP specification only requires that timestamps be increasing within a type. Timestamps can be out of order across different types. On the contrary, Akamai requires timestamps monotonically increasing across types.

Solution

Please try the following to resolve the issue:

• Restart the encoder. The encoder may reset all values and start sending ordered packets as normal.
• Try streaming with OBS studio to check if the same issues are happening with another encoder.

If neither of these work, contact your encoder company to see what support they can offer.

Please note that this information comes directly from Akamai which is one of our CDNs.

If you have any questions about live streaming CDN’s or need help with this Dacast feature, feel free to contact us directly.

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Additional Resources:

• Why are My Video and Audio Out of Sync?
• How to Troubleshoot Your HLS Live Stream
• Why Do I See a “Sorry, This Media is Offline” Message?
• Encoder Setup Guide for the New Dacast Platform
• CDN For Live Streaming: What to Look For?