Error Message:

Warn 200: Duration is out of bounds, marking as discontinuity 

Issue:

Discontinuity when keyframe interval is larger than Cupertino chunk duration target.

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Cupertino settings:

The chunks for HTTP based playback protocols like Apple HLS require a keyframe to start a chunk. This means that the keyframe interval of the source stream will affect the chunk duration. A new Cupertino boundary was introduced in Streaming Engine version 4.8.15.

This keyframe interval boundary is 3X the cupertinoChunkDurationTarget value.

Let's look at an example:

Before the release of Streaming Engine 4.8.15:

1. If the cupertinoChunkDurationTarget (in milliseconds) is configured with a value of 1000, so the following would happen:

• A source with a keyframe interval of 1 second would result in 1-second chunks.
• A source with a keyframe interval of 2 seconds would result in 2-second chunks.
• A source with a keyframe interval of 4 seconds would result in 4-second chunks (and so on).

     2. In Streaming Engine version 4.8.15 and newer, there is now a boundary which means:

• A source with a keyframe interval of 4 seconds will result in 4-second chunks that is outside the bounds of 3X(1000ms) that we used for our example. This will result in a stream that cannot be played as every chunk will be a discontinuity.

Troubleshooting:

• Adjust the keyframe interval of the source to be within the new boundary (3X the cupertinoChunkDurationTarget value).
• Increase the value of the cupertinoChunkDurationTarget if this has been reduced from the default of 10000.

Additional Resources:

Configure Apple HLS packetization for Wowza Streaming Engine