How to reduce delay before video playback starts

This article describes two methods you can use to reduce the time delay that occurs during the time after a client receives a stream and before playback starts.

Method 1: Increase keyframe frequency

Increase the keyframe frequency (fps) value in your encoder to speed up the playback start time. Adobe Flash RTMP clients wait for a keyframe and at least 60 frames before playback starts.

Method 2: Speed up start time

You can speed up playback start time at the expense of increasing latency by adding application properties. This method causes playback to start further behind the live point so only do this if a quick start time is important. If low latency is important to your workflow, don't use this method. Use of these properties requires some experimentation and testing.

You can configure application properties in Wowza Streaming Engine™ Manager or by editing [install-dir]/conf/[application]/Application.xml. If you make changes to Application.xml and you're using the Wowza Streaming Engine media server software, any supported settings are displayed in the manager the next time it's started. Wowza Media Server™ software doesn't support Wowza Streaming Engine Manager, so you must edit Application.xml in a text editor if you're running Media Server software.

Wowza Streaming Engine Manager configuration
  1. In the manager Welcome page, click the Applications tab at the top of the page.
  2. In the Applications contents panel, click the name of your live application (such as live).
  3. On the live application page Properties tab, click Custom in the Quick Links bar.
    Note: Access to the Properties tab is limited to administrators with advanced permissions. For more information, see Manage credentials.
  4. In the Custom area, click Edit.
  5. Click Add Custom Property, specify the following settings in the Add Custom Property dialog box, and then click Add:
    • Path - /Root/Application/Streams
    • Name - instantOn
    • Type - Boolean
    • Value - true
  6. Repeat step 5 to add the instantOnBufferTime property using the following values:
    • Path - /Root/Application/Streams
    • Name - instantOnBufferTime
    • Type - Integer
    • Value - 3000
  7. Click Save, and then restart the application when prompted to apply the changes.

XML configuration
  1. Use a text editor to open the [install-dir]/conf/[application]/Application.xml file for your live application and add the following property to the Streams/Properties container. Be sure to add the properties to the correct <Properties> container in Application.xml as there are several such containers in the file.
  2. Restart the Wowza media server software to apply the changes.

Originally Published: 12-04-2014.
Updated: For Wowza Streaming Engine 4.2 on 06-28-2015.

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