AVImageGenerator

Overview

The AVImageGenerator module provides the APIs for extracting video frames at given time points from videos.

System capability: SystemCapability.Multimedia.Media.AVImageGenerator

Since: 18

Summary

Files

Name	Description
avimage_generator.h	Declares the AVImageGenerator APIs. With these native APIs, you can extract video frames at given time points from videos.
avimage_generator_base.h	Declares the enums used by the AVImageGenerator.

Types

Name	Description
typedef struct OH_AVImageGenerator OH_AVImageGenerator	Defines a struct for the OH_AVImageGenerator.
typedef enum OH_AVImageGenerator_QueryOptions OH_AVImageGenerator_QueryOptions	Defines an enum for the mappings between time points and video frames.

Enums

Name	Description
OH_AVImageGenerator_QueryOptions { OH_AVIMAGE_GENERATOR_QUERY_NEXT_SYNC = 0, OH_AVIMAGE_GENERATOR_QUERY_PREVIOUS_SYNC = 1, OH_AVIMAGE_GENERATOR_QUERY_CLOSEST_SYNC = 2, OH_AVIMAGE_GENERATOR_QUERY_CLOSEST = 3 }	Enumerates the mappings between time points and video frames.

Functions

Name	Description
OH_AVImageGenerator * OH_AVImageGenerator_Create (void)	Creates an OH_AVImageGenerator instance.
OH_AVErrCode OH_AVImageGenerator_SetFDSource (OH_AVImageGenerator *generator, int32_t fd, int64_t offset, int64_t size)	Sets a data source based on the media file descriptor.
OH_AVErrCode OH_AVImageGenerator_FetchFrameByTime (OH_AVImageGenerator generator, int64_t timeUs, OH_AVImageGenerator_QueryOptions options, OH_PixelmapNative *pixelMap)	Extracts a video frame at a given time from a video.
OH_AVErrCode OH_AVImageGenerator_Release (OH_AVImageGenerator *generator)	Releases the resources used by the OH_AVImageGenerator instance and destroys the instance.

Type Description

OH_AVImageGenerator

typedef struct OH_AVImageGenerator OH_AVImageGenerator

Description

Defines a struct for the OH_AVImageGenerator.

System capability: SystemCapability.Multimedia.Media.AVImageGenerator

Since: 18

OH_AVImageGenerator_QueryOptions

typedef enum OH_AVImageGenerator_QueryOptions OH_AVImageGenerator_QueryOptions

Description

Defines an enum for the mappings between time points and video frames.

System capability: SystemCapability.Multimedia.Media.AVImageGenerator

Since: 18

Enum Description

OH_AVImageGenerator_QueryOptions

enum OH_AVImageGenerator_QueryOptions

Description

Enumerates the mappings between time points and video frames.

System capability: SystemCapability.Multimedia.Media.AVImageGenerator

Since: 18

Value	Description
OH_AVIMAGE_GENERATOR_QUERY_NEXT_SYNC	Extracts the key frame at or next to the specified time.
OH_AVIMAGE_GENERATOR_QUERY_PREVIOUS_SYNC	Extracts the key frame at or prior to the specified time.
OH_AVIMAGE_GENERATOR_QUERY_CLOSEST_SYNC	Extracts the key frame closest to the specified time.
OH_AVIMAGE_GENERATOR_QUERY_CLOSEST	Extracts the frame (not necessarily a key frame) closest to the specified time.

Function Description

OH_AVImageGenerator_Create()

OH_AVImageGenerator* OH_AVImageGenerator_Create(void)

Description

Creates an OH_AVImageGenerator instance.

System capability: SystemCapability.Multimedia.Media.AVImageGenerator

Since: 18

Returns

Returns the pointer to the OH_AVImageGenerator instance created if the operation is successful; returns a null pointer otherwise.

Possible cause of failures: HstEngineFactory fails to create an AVMetadataHelperEngine.

OH_AVImageGenerator_FetchFrameByTime()

OH_AVErrCode OH_AVImageGenerator_FetchFrameByTime(OH_AVImageGenerator* generator, int64_t timeUs, OH_AVImageGenerator_QueryOptions options, OH_PixelmapNative** pixelMap)

Description

Extracts a video frame at a given time from a video.

This function must be called after SetFDSource.

System capability: SystemCapability.Multimedia.Media.AVImageGenerator

Parameters

Name	Description
generator	Pointer to an OH_AVImageGenerator instance.
timeUs	Time point of the video frame to be extracted in the video, in μs.
options	Mappings between the given time points and video frames. For details, see OH_AVImageGenerator_QueryOptions.
pixelMap	Double pointer to the video frame object obtained. For details, see {@link OH_PixelmapNative}.

Returns

Returns a result code defined in OH_AVErrCode. The following result codes are possible:

AV_ERR_OK: The operation is successful.

AV_ERR_INVALID_VAL: The input parameter generator is a null pointer or an input parameter is invalid.

AV_ERR_OPERATE_NOT_PERMIT: The operation is not allowed.

AV_ERR_UNSUPPORTED_FORMAT: The format is not supported.

AV_ERR_NO_MEMORY: Internal memory allocation failed.

OH_AVImageGenerator_Release()

OH_AVErrCode OH_AVImageGenerator_Release(OH_AVImageGenerator* generator)

Description

Releases the resources used by the OH_AVImageGenerator instance and destroys the instance.

System capability: SystemCapability.Multimedia.Media.AVImageGenerator

Since: 18

Parameters

Name	Description
generator	Pointer to an OH_AVImageGenerator instance.

Returns

Returns a result code defined in OH_AVErrCode. The following result codes are possible:

AV_ERR_OK: The operation is successful.

AV_ERR_INVALID_VAL: The input parameter generator is a null pointer or an input parameter is invalid.

OH_AVImageGenerator_SetFDSource()

OH_AVErrCode OH_AVImageGenerator_SetFDSource(OH_AVImageGenerator* generator, int32_t fd, int64_t offset, int64_t size)

Description

Sets a data source based on the media file descriptor.

System capability: SystemCapability.Multimedia.Media.AVImageGenerator

Since: 18

Parameters

Name	Description
generator	Pointer to an OH_AVImageGenerator instance.
fd	File descriptor of the media source.
offset	Offset of the media source in the file descriptor.
size	Size of the media source.