This topic describes features of MediaLive.
Overview
MediaLive provides the following features: input association, protocol conversion, video transcoding, and audio track composition.
Input association: Add multiple external video sources to MediaLive for processing, such as obtaining a video stream, filtering audio streams, and merging video and audio streams for channel output.
Protocol conversion: Configure multiple output groups that use different streaming protocols for a channel. The output group converts the protocol of the video and audio streams merged in the previous step to the required protocol.
Video transcoding: Configure the transcoding format for an output. For example, you can convert an original video stream from 1080P to 720P.
Audio track composition: Configure audio tracks for an output. The audio tracks are combined with the video track transcoded and packaged in the specified format to form an output to MediaPackage.
An output group consists of one or more outputs. Each output contains a specific combination of video and audio tracks.
Input association
Associate a configured input with a channel. You can configure an audio selector to extract audio from the input. Then, only specified audio tracks from the input source can be used in the output.
The audio selector is optional. An RTMP input supports only one audio selector, while an SRT input supports multiple selectors.
For more iconfiguration information, see Audio selector parameters.
A channel supports only one video stream and multiple audio streams. By default, the video stream of the first input is used.
Protocol conversion
This feature is used to convert the streaming protocol of the source video to the required protocol. For more information, see Output group parameters.
MediaLive only supports delivering content to MediaPackage over the HLS protocol.
Video transcoding
This feature is used to modify the encoding parameters of the original video. It also supports advanced configurations, such as ad marker passthrough, transcoding templates, and 4K transcoding.
Ad marker passthrough: Supports pass-through specified SCTE-35 messages from the input source to the output.
Transcoding templates: Supports two types of video transcoding templates
Regular transcoding: Supports up to 4K resolution.
Narrowband HD™ transcoding: Uses Alibaba Cloud's proprietary algorithm to achieve lower data usage with the same image quality or higher definition video with the same bandwidth. Supports up to 1080P resolution.
4K transcoding: Provides real-time encoding for 2K and 4K high-resolution content.
For more information, see Output group parameters.
Audio track composition
This feature is used to extract audio tracks from inputs by using the audio selector and combine them with other audio and video streams for outputs.
When associating an input with a channel, configure the audio selectors for the required audio tracks. Then, select the appropriate configured audio selectors for an output.