Introduction

In a video-on-demand scenario, when the playback progress bar is dragged, the end user will send a URL request, such as http://www.aliyun.com/test.flv?start=10, to the server. The server returns the data from the key frame prior to the10th second to the client (If start=10 is not the key frame).  

After receiving such a request from an end user and the Drag/Drop Playback function is enabled, a CDN node can directly return the data from the key frame prior to the10th second (If start=10 is not the key frame) (FLV format) or from the 10th second to the end user.

Note

  • To use the Drag/Drop Playback function, an origin site must support Range requests. The origin site must be able to return correct 206 Partial Content for an HTTP request header containing a Range field.
  • Two available file format: MP4 and FLV.
  • Currently, FLV format only supports the coding formats with the audio format of aac and video format of avc.
File Format Meta Information start Parameter Example
MP4 Meta information of an origin site video must be contained in the file header. A video with its meta information contained in the file tail is not supported. The start parameter specifies the time in seconds. Decimals are supported to indicate milliseconds. For example, start=1.01 indicates that the start time is 1.01s. If the current start is not a key frame, the CDN locates the key frame prior to the time specified by the start parameter. The request http: //domain/video.mp4?start=10  playing a video from the 10th second.
FLV An origin site video must contain meta information. The start parameter specifies a byte. If the current start is not a key frame, the CDN automatically locates the key frame prior to the frame specified by the start parameter. For http: //domain/video.flv, the request http:// domain/video.flv? start=10 playing a video from the key frame prior to the10th byte( If start=10 is not the position of the key frame) .

Procedure

  1. Go to Domain Namespage, select the domain name, then click Manage.
  2. Enable the function in Video-related > Drag/Drop Playback.