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Last updated: 2023-03-07 11:20:50

Screenshot taking is an offline task that takes screenshots of a video at specified times. VOD supports the following types of screenshots:
Time point screenshot: Takes screenshots at specified time points.
Sampled screenshot: Takes screenshots at regular intervals.
Thumbnail: Takes a screenshot at a specified time point and uses it as the video’s thumbnail.
Image sprite: Takes multiple screenshots at the specified interval and combines them into one image (image sprite).
Common use cases include the following:
Video thumbnail generation: Take a screenshot of a video and use it as the video’s thumbnail.
Image sprite generation: Generate an image sprite (a collection of small images), which is often used as the summary of a video.
Preview: Use image sprites and VTT files to show previews above the progress bar.
Screenshot Templates
A screenshot template is a collection of screenshot parameters, including the output file format and image dimensions.
Time point screenshot templates
You can use a time point screenshot template to take a screenshot at a specific time point or generate a thumbnail.
Parameter
Description
Format
The screenshot format (only JPG is supported currently).
Width
The screenshot width (px). Value range: 128-4096.
Height
The screenshot height (px). Value range: 128-4096.
FillType
The fill mode (FillType) specifies how the source video is processed when its aspect ratio does not match the output aspect ratio. The following fill modes are supported: 
Stretch: The source video is stretched to match the output aspect ratio. This may cause the video to appear distorted.
Fill with black: The original aspect ratio is retained, leaving black bars.
Fill with white: The original aspect ratio is retained, leaving white bars.
Gaussian blur: The original aspect ratio is retained, and Gaussian blur is applied to the blank spaces.
VOD provides preset time point screenshot templates for common parameter combinations. You can also create your own templates and manage them in the console. For details, see Template Settings.
Sampled screenshot templates
You can use a sampled screenshot template to take screenshots at regular intervals.
Parameter
Description
Format
The screenshot format (only JPG is supported currently).
Width
The screenshot width (px). Value range: 128-4096.
Height
The screenshot height (px). Value range: 128-4096.
SampleType
How sampling intervals are measured. Sampling intervals can be measured in two ways:
By percent: Intervals are measured by percent. For example, if Interval is set to 5 (%), 20 screenshots will be generated for a video.
By time: Intervals are measured by time. For example, if Interval is set to 10 (sec), the number of screenshots generated will depend on the video length.
Interval
The sampling interval.
If the interval measurement (SampleType) is by percent, this parameter is a percent value.
If interval measurement is by time, this parameter is a time value (sec).
FillType
The fill mode (FillType) specifies how the source video is processed when its aspect ratio does not match the output aspect ratio. The following fill modes are supported:
Stretch: The source video is stretched to match the output aspect ratio. This may cause the video to appear distorted.
Black-leaving: The original aspect ratio is retained, leaving black bars.
Blank-leaving: The original aspect ratio is retained, leaving blank spaces.
Gaussian blur: The original aspect ratio is retained, and Gaussian blur is applied to the blank spaces.
VOD provides preset sampled screenshot templates for common parameter combinations. You can also create your own templates and manage them in the console. For details, see Template Settings.
Image sprite screenshot templates
You can use an image sprite screenshot template to generate image sprites.
Parameter
Description
Format
The format of the image sprite (only JPG is supported currently).
Width
The width of the subimage in an image sprite.
Height
The height of the subimage in an image sprite.
Rows
The number of image rows in a sprite.
Columns
The number of image columns in a sprite.
SampleType
How sampling intervals are measured. Currently, only sampling by time is supported.
Interval
The time interval for image sampling.
Note: 
The result of multiplying Width x Columns (i.e., sprite width) should be within the range of 128-4096.
The result of multiplying Height x Rows (i.e., sprite height) should be in the range of 128-4096.
VOD provides preset image sprite screenshot templates for common parameter combinations. You can also create your own templates and manage them in the console. For details, see Template Settings.
Initiating a Screenshot Task
You can initiate a screenshot taking task by calling a server API, via the console, or by specifying the task when uploading videos. For details, see Task Initiation.
Specifically, you can initiate a screenshot task by doing one of the following:
Call the server API ProcessMedia, specifying the ID of the screenshot template in MediaProcessTask.SnapshotByTimeOffsetTaskSet.
Add a task flow in the console, specifying the screenshot parameters, and use the task flow to process videos in the console.
Add a task flow in the console, specifying the screenshot parameters. When uploading a video from the server, set the procedure parameter to the task flow you created.
Add a task flow in the console, specifying the screenshot parameters. When uploading a video from a client, set procedure in the upload signature to the task flow you created.
Add a task flow in the console, specifying the screenshot parameters. When uploading a video via the console, choose Auto-processing after upload and select the task flow you created.
Getting the Result
After initiating a screenshot task, you can wait for the result notification asynchronously or perform a task query synchronously to get the task execution result. Below is an example of the notification received in normal callback mode after a screenshot task is initiated (the fields with null value are omitted):
{
    "EventType":"ProcedureStateChanged",
    "ProcedureStateChangeEvent":{
        "TaskId":"1256768367-Procedure-2e1af2456351812be963e309cc133403t0",
        "Status":"FINISH",
        "FileId":"5285890784246869930",
        "FileName":"Animal World",
        "FileUrl":"http://1256768367.vod2.myqcloud.com/xxx/xxx/AtUCmy6gmIYA.mp4",
        "MetaData":{
            "AudioDuration":60,
            "AudioStreamSet":[
                {
                    "Bitrate":383854,
                    "Codec":"aac",
                    "SamplingRate":48000
                }
            ],
            "Bitrate":1021028,
            "Container":"mov,mp4,m4a,3gp,3g2,mj2",
            "Duration":60,
            "Height":480,
            "Rotate":0,
            "Size":7700180,
            "VideoDuration":60,
            "VideoStreamSet":[
                {
                    "Bitrate":637174,
                    "Codec":"h264",
                    "Fps":23,
                    "Height":480,
                    "Width":640
                }
            ],
            "Width":640
        },
        "MediaProcessResultSet":[
            {
                "Type":"SnapshotByTimeOffset",
                "SnapshotByTimeOffsetTask":{
                    "Status":"SUCCESS",
                    "ErrCode":0,
                    "Message":"",
                    "Input":{
                        "Definition":10,
                        "Definition":[3, 6, 9]
                    },
                    "Output":{
                        "Definition":10,
                        "PicInfoSet":[
                            {
                                "TimeOffset":3,
                                "Url":"http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx1.jpg"
                            },
                            {
                                "TimeOffset":6,
                                "Url":"http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx2.jpg"
                            },
                            {
                                "TimeOffset":9,
                                "Url":"http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx3.jpg"
                            }
                        ]
                    }
                }
            },
            {
                "Type":"SampleSnapshot",
                "SampleSnapshotTask":{
                    "Status":"SUCCESS",
                    "ErrCode":0,
                    "Message":"",
                    "Input":{
                        "Definition":10
                    },
                    "Output":{
                        "Definition":10,
                        "SampleType": "Percent",
                        "Interval": 10,
                        "WaterMarkDefinition": [],
                        "ImageUrlSet":[
                                "http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx1.jpg",
                                "http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx2.jpg",
                                "http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx3.jpg",
                                "http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx4.jpg",
                                "http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx5.jpg",
                                "http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx6.jpg",
                                "http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx7.jpg",
                                "http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx8.jpg",
                                "http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx9.jpg"
                        ]
                    }
                }
            },
            {
                "Type":"ImageSprites",
                "ImageSpriteTask":{
                    "Status":"SUCCESS",
                    "ErrCode":0,
                    "Message":"",
                    "Input":{
                        "Definition":10
                    },
                    "Output":{
                        "Definition":10,
                        "Height":80,
                        "Width":142,
                        "TotalCount":1,
                        "ImageUrlSet":[
                            "http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx1.jpg"
                        ],
                        "WebVttUrl":"http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx.vtt"
                    }
                }
            },
            {
                "Type":"CoverBySnapshot",
                "CoverBySnapshotTask":{
                    "Status":"SUCCESS",
                    "ErrCode":0,
                    "Message":"",
                    "Input":{
                        "Definition":10,
                        "PositionType":"Time",
                        "PositionValue":0
                    },
                    "Output":{
                        "CoverUrl":"http://1256768367.vod2.myqcloud.com/xxx/xxx/xxx.jpg"
                    }
                }
            }
        ],
        "TasksPriority":0,
        "TasksNotifyMode":""
    }
}
In the above callback, ProcedureStateChangeEvent.MediaProcessResultSet contains four types of results, namely SnapshotByTimeOffset, SampleSnapshot, ImageSprites, and CoverBySnapshot, which represent a time point screenshot task, a sampled screenshot task, an image sprite screenshot task, and a thumbnail generation task respectively.

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Recent Pages

Screenshots

Screenshot Templates

Time point screenshot templates

Sampled screenshot templates

Image sprite screenshot templates

Initiating a Screenshot Task

Getting the Result

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Parameter	Description
Format	The screenshot format (only JPG is supported currently).
Width	The screenshot width (px). Value range: 128-4096.
Height	The screenshot height (px). Value range: 128-4096.
FillType	The fill mode (`FillType`) specifies how the source video is processed when its aspect ratio does not match the output aspect ratio. The following fill modes are supported: Stretch: The source video is stretched to match the output aspect ratio. This may cause the video to appear distorted. Fill with black: The original aspect ratio is retained, leaving black bars. Fill with white: The original aspect ratio is retained, leaving white bars. Gaussian blur: The original aspect ratio is retained, and Gaussian blur is applied to the blank spaces.

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Recent Pages

Screenshots

Screenshot Templates

Time point screenshot templates

Sampled screenshot templates

Image sprite screenshot templates

Initiating a Screenshot Task

Getting the Result

Was this page helpful?

Was this page helpful?