Fixed, immediate, and follow switches - AWS Elemental MediaLive

Fixed, immediate, and follow switches

You can categorize input switches according to the start types for the switch.

  • Fixed – A fixed input switch starts at a specific time.

    Fixed switches use UTC time. They don't use the timecode of the input.

  • Immediate – An immediate input switch starts as soon as possible. This type of switch is more like a fixed switch than a follow switch because it interrupts the current input. The advantage of this switch over a fixed switch is that you don't have to calculate any buffer in the start time.

  • Follow – A follow input switch starts when the previous input has ended (when MediaLive has reached the end of the file).

This start type is a property of the switch, not a property of the input itself. Therefore, in the schedule you can switch to a specific input with a fixed switch, and then later switch to the same input with a follow switch.

Types of switches and types of inputs

The combination of types of switches and types of inputs (file and live) means that there are these types of switches:

  • A file input with a fixed start. The previous input can be a file or live input. At the specified start time, MediaLive stops ingesting the previous input and switches to the new input.

  • A file input with an immediate start. The previous input can be a file or a live input. As soon as possible after you enter this switch in the schedule, MediaLive stops ingesting the previous input and switches to the new input.

  • A file input that follows the previous input. The previous input must be a file input. It can't be a live input because a live input doesn't have an end, so the switch would never occur.

  • A live input with a fixed start. The previous input can be a file or live input. At the specified start time, MediaLive stops ingesting the previous input and switches to the new input.

  • A live input with an immediate start. The previous input can be a file or a live input. As soon as possible after you enter this switch in the schedule, MediaLive stops ingesting the previous input and switches to the new input.

  • A live input that follows the previous input. The previous input must be a file input. It can't be a live input because a live input doesn't have an end, so the switch would never occur.

The following table summarizes the inputs and start types.

Current Input Next Input Possible Start Type
File File Fixed or Immediate
File File Follow
File Live Fixed or Immediate
File Live Follow
Live File Fixed or Immediate
Live Live Fixed or Immediate

Follow chains

A series of follow input switches is called a follow chain. When each input ends, MediaLive automatically starts ingesting the next input. Here is a diagram of a follow chain:

Input A Fixed or Immediate File Input B Follow File Input C Follow File Input D Follow File or Live Input E Fixed or Immediate File or Live

The follow chain starts with the reference action—the input above the first follow. It ends with the last follow input. In the preceding example, the chain starts with the reference action input A and ends with input D. Inputs A, B, and C must be files because they must have a defined ending so that the next input can successfully follow. Input E breaks the chain because it is fixed or immediate.