With Wowza Streaming Engine™ media server software, you can stream lower-latency Apple HLS content smoothly. You can reduce the latency of Apple HLS streams by using smaller chunk sizes, which may result in playback errors if Wowza Streaming Engine uses the default behavior of returning three chunks at a time to the player. This article describes how to configure Wowza Streaming Engine to store and return more chunks to the player upon request for smooth playback of lower-latency Apple HLS streams.
In Wowza Streaming Engine Manager, click the Applicationstab and then click livein the contents panel.
On the details page Propertiestab, click Cupertino Streaming Packetizerin the Quick Links bar.
In the Cupertino Streaming Packetizerarea, click Edit, and change the values for the following properties:
cupertinoChunkDurationTarget- Sets the duration of each chunk in milliseconds. The default value is 10000, but the chunkDurationTargetmust be smaller to reduce the latency of Apple HLS streams. For a one-second chunk size, set the value to 1000.
cupertinoMaxChunkCount- Sets the maximum number of chunks Wowza Streaming Engine stores in the available chunk list. The default value is 10, but for reduced latency streaming we recommend storing 50 seconds worth of chunks. For one-second chunks, set the cupertinoMaxChunkCountto 50; if you're using half-second chunks, the value should be doubled (100).
cupertinoPlaylistChunkCount- Sets the number of items returned to the player in the playlist. The default value is 3, but for reduced latency streaming we recommend returning 12 seconds of data to the player. This prevents the loss of chunks between chunklist requests. For one-second chunks, set the cupertinoPlaylistChunkCountto 12; if you're using half-second chunks, the value should be doubled (24).
On the Propertiestab, click Customin the Quick Links bar.
In the Customarea, click Edit.
ClickAdd Custom Property, specify the following custom property settings in the Add Custom Propertydialog box, and then click Add:
In Path, select /Root/Application/LiveStreamPacketizer.
In Name, enter cupertinoMinPlaylistChunkCount.
In Type, select Integer.
In Value, specify the minimum number of chunks required before Wowza Streaming Engine provides a playlist to the player. The default value is 1, but for reduced latency streaming we recommend requiring a minimum of 6 seconds worth of chunks. For one-second chunks, set the cupertinoMinPlaylistChunkCountto 6; if you're using half-second chunks, the value should be doubled (12).
Click Saveand restart the application to to apply the changes.