Streams section - AWS Elemental MediaLive

Streams section

In Stream settings, decide if you need to create more encodes for this output, based on the workflow that you planned. By default, each output is set up with one video encode and one audio encode. Choose the appropriate Add button or Delete button to set up the output with the encodes—video, audio, and captions—that you planned for this output.

For example, in one output you might want one video asset and two audio assets, in another output you might want one captions asset for French captions, and in a third output you might want one captions asset for Spanish captions. For information about why you would set up like this (for example, with an output that contains only one captions asset), see Examples of channel designs.

Packaging of video encodes and audio-only encodes

MediaLive handles the packaging of encodes within each output as follows:

  • If an output contains both video and audio (and optionally captions), the audio rendition is marked as program audio.

  • If an output doesn't contain video, the audio rendition is marked as audio only and each audio encode is marked as ALTERNATE_AUDIO_NOT_AUTO_SELECT.

Setting the width and height of the video

This section refers to the fields in Stream settings, Video.

You must specify values in Width and Height. The MediaPackage output group doesn't support leaving these fields blank to use the width and height from the source video.

Setting the aspect ratio of the video

This section refers to the fields in Stream settings, Video, Aspect ratio.

You must set PAR control to SPECIFIED. The MediaPackage output group doesn't support setting the aspect ratio of the output to follow the source video. When you choose SPECIFIED, you must complete PAR numerator and PAR denominator. You can set the AFD fields as you want.

Setting the frame rate of the video

This section refers to the fields in Stream settings, Video, Frame rate.

You must set Framerate control to SPECIFIED. The MediaPackage output group doesn't support setting the frame rate of the output to follow the source video. When you choose SPECIFIED, you must complete Framerate numerator and Framerate denominator. You can set the scan type as you want; it doesn't relate directly to the frame rate.

Setting up for GOPs and segments

This section refers to the fields in Stream settings, Video, GOP structure.

For the video, you must set the GOP size to ensure that the output from MediaLive has a segment size that is close to the segment size that you specify in MediaPackage. MediaLive and MediaPackage work together to obtain a final segment size. The logic is as follows:

  • In MediaLive you specify the GOP size and GOP size units fields.

  • MediaLive calculates the GOP duration, taking into account the frame rate that you specify in the Video section of the Output page.

  • In MediaPackage you specify the segment duration. You always specify a whole number. This segment duration is the desired minimum duration.

  • When MediaPackage receives the video from MediaLive, it determines how much it must adjust the segment duration to fit a whole number of GOPs into the segment. The segment duration can only be adjusted up, never down. This adjusted segment duration appears in the manifest that MediaPackage produces.

Example 1

Assume that in MediaLive you set the GOP size to 60 frames. You set the frame rate to 29.97. These two values result in a GOP duration of 2.002 seconds.

Assume that in MediaPackage you set the segment duration to 6 seconds. This segment duration is the desired minimum duration.

When MediaPackage receives the video from MediaLive, it determines how much it must adjust the segment duration to fit a whole number of GOPs into the segment. In this case, the segment duration must be adjusted to 6.006 seconds (three GOPs, where each GOP is 2.002 seconds long).

Example 2

Assume that in MediaLive, you set the GOP size to 90 frames. You set the frame rate to 30. These two values result in a GOP duration of 3 seconds.

Assume that in MediaPackage you set the segment duration to 4 seconds. This segment duration is the desired minimum duration.

When MediaPackage receives the video from MediaLive, it determines how much it must adjust the segment duration to fit a whole number of GOPs into the segment. In this case, the segment duration must be adjusted to 6 seconds (two GOPs, where each GOP is 3 seconds long).

Other encode fields

For information about the fields in each type of encode, see the following sections: