Video seeking is a feature in on-demand video/audio streaming where a client sends a URL request to the server when the playback progress is adjusted.-阿里云帮助中心

In on-demand video/audio streaming scenarios, the video processing feature of ESA provides a seamless playback experience by identifying the nearest previous keyframe to the requested playback position and loading the corresponding video segment.

Prerequisites

The origin server supports HTTP Range requests.
The query string is set to Retain All.

Add a video processing rule

In the ESA console, choose Websites and click the target site in the Website column.
In the navigation pane on the left, choose Rules > Content Optimization.
Select the Video Processing tab, click Create Rule, and then enter a Rule Name.
In the If requests match... area, set the conditions for matching user requests. For more information about how to configure rules, see Composition of rule expressions.

In the Video Seeking area, click Configure, turn on the Status switch, and then configure the parameters.

For example, if a URL request for an FLV file is www.aliyun.com/test.flv?start=10, the server returns data starting from the keyframe that precedes the 10th byte. The following table describes the file and URL formats that the video seeking feature supports.

File format

Meta information

Parameters

Example

MP4

The meta information of the source video must be in the file header. Videos with meta information at the end of the file are not supported.

The start parameter specifies the time in seconds. It supports up to three decimal places. For example, start=1.01 indicates that playback starts at 1.01 seconds.

If the time specified by start is not a keyframe, ESA automatically locates the previous keyframe.
If the time specified by start is a keyframe, ESA automatically locates the current keyframe.

Custom MP4 Parameters notes:

The start parameter is start by default, and the end parameter is end by default.
Custom parameters can contain only uppercase letters, lowercase letters, digits, and underscores (_). For example: 123, aabbAABB, and aa_BB123.

A URL request is domain/video.mp4?start=10, which indicates that the video playback starts from the 10th second.

FLV

The source video must contain meta information.

The start parameter specifies the byte. Decimals are not supported. Although you can specify a decimal in the parameter, the video seeking module rounds it down to a positive integer.

FLV Seeking By Time: The unit for the start and end parameters is seconds.

Seeking By Byte: Seeking by byte is suitable for precise data processing or processing raw video data. Seeking by second provides a user-friendly experience by directly jumping to the requested second.

If the time specified by start is not a keyframe, ESA automatically locates the previous keyframe.
If the time specified by start is a keyframe, ESA automatically locates the current keyframe.

Notes On Custom Parameters For Video Seeking:

The start parameter is start by default, and the end parameter is end by default.
Custom parameters can contain only uppercase letters, lowercase letters, digits, and underscores (_). For example: 123, aabbAABB, and aa_BB123.

A URL request is domain/video.flv?start=10, which indicates that the video playback starts from the keyframe before the 10th byte.

Handling drag-and-drop parameters

For example, when seeking by time, the default video seeking parameters are start and end. The following tables describe the processing logic for parameter values in different scenarios:

MP4 file requests

start/end value	Example	Handling Drag-and-Drop
Invalid `start` and invalid `end`	`start=foo&end=bar`	Ignores the video seeking parameters and responds with the complete video.
Valid `start` and invalid `end`	`start=10`	Drag-and-drop processing time for `10` files.
Invalid `start` and valid `end`	`end=10`	Processes video seeking from `0-10`.
Valid `start` and valid `end`	`start=0&end=10`	Processes video seeking from `0-10`.
`start` and `end` are both `0`	`start=0&end=0`	Ignores the video seeking parameters and responds with the complete video.
`start` is greater than `end`	`start=10&end=0`	Drag-and-drop processing time for `10` files.
`start` is equal to `end`	`start=10&end=10`	Drag-and-drop processing: `10`-file processing time.
`start` is greater than the video duration	`start` is greater than the video duration	Returns `400`.

FLV file requests

start/end value	Example	Drag-and-drop handling logic
Invalid `start` and invalid `end`	`start=foo&end=bar`	Ignores the video seeking parameters and responds with the complete video.
Valid `start` and invalid `end`	`start=10`	Drag-and-drop processing: Duration for `10` files.
Invalid `start` and valid `end`	`end=10`	Processes video seeking from `0-10`.
Valid `start` and valid `end`	`start=0&end=10`	You can process the range `0-10` by dragging and dropping.
`start` and `end` are both `0`	`start=0&end=0`	Ignores the video seeking parameters and responds with the complete video.
`start` is greater than `end`	`start=10&end=0`	You can drag and drop a file with a length of `10` to process it.
`start` is equal to `end`	`start=10&end=10`	Handles drag-and-drop operations for `10` files.
`start` is greater than the video duration	`start` is greater than the video duration	Returns the complete video.

References

Rule-related features vary in execution priority, rule behavior, and configuration scope. For more information, see How ESA rules take effect.