1 VAS Intro

1.1 Brief Introduction

Internet live streaming business involves various types of watching devices and qualities of access network. Thus, content providers need to provide video content in various bitrates for customers to choose. Some content providers are providing self-adaptive bitrates so that users can access video content with the most appropriate bitrates and gain the best experience. In the interactive live streaming business, the anchor usually pushes a stream, requiring CDNetworks to output multiple streams with different bitrates to provide end users with self-adaptive bitrates.
To meet this requirement, CDNetworks rolls out the feature of live transcoding, with which customers can input a high bitrate stream to the CDN platform. Afterwards, the transcoding center of the platform will output multiple live streams with different bitrates in real time based on agreed requirements. In this way, various customer needs customers are fulfilled.

1.2 Applicable Product Line

• Media Acceleration Live Broadcast.

1.3 Application Scenarios

1. When customers need to provide audios/videos in different bitrates for users.
2. When customers need to add a watermark to live streams.
3. When customers need the feature of adaptive bitrates.

2 Feature Detail

2.1 Feature Description

This introduction mainly focuses on different elements of the feature and briefs customers on how to use them. These feature elements can be customized.

The live transcoding feature provides transcoding service in response to user requests and requirements. In other words, live transcoding is only triggered when end user requests for transcoded live streams. If end users do not request transcoded live streams, transcoding will not be performed. On-demand transcoding minimizes the transcoding costs for customers.
Live Transcoding includes below functionalities:

• Live H.264 Transcoding
• Live H.265 Transcoding
• HLS Adaptive Bitrate
• Live Stream Watermarking
• Audio Stream Transcoding
• Live Stream Trans-protocol
  Supported transcoding parameters
  Bitrate, resolution, audio/video codec, keyframe interval, video watermarking, etc.
  Transcoding request methods
  Triggered by requests from player:
  General live streaming request: http://test.com/live/channel.flv;
  Transcoding live streaming request: http://test.com/live/channel_a.flv;
  Note: “_a” represents a combination of transcoding (fixed bitrate, resolution, audio/video codec, keyframe interval, video watermarking) and needs to be negotiated with customers.

2.2 Instructions

Please pay attention to the following points when using transcoding:

• Confirm the output and input parameters for transcoding.
• Confirm the URL format of the requests sent from end users.
• Confirm whether adaptive bitrate is needed after transcoding

3 Notices

• When using transcoding service, 3-4 seconds of delay might occur in live streaming.
• Live transcoding feature only works when the input is a stream, that is RTMP/HTTP FLV/HTTP TS. Transcoding is not supported when the input is HLS/HDS.