1# OH_AVDataSource 2 3 4## Overview 5 6The OH_AVDataSource struct describes a user-defined data source. 7 8**System capability**: SystemCapability.Multimedia.Media.CodecBase 9 10**Since**: 12 11 12**Related module**: [CodecBase](_codec_base.md) 13 14 15## Summary 16 17 18### Member Variables 19 20| Name| Description| 21| -------- | -------- | 22| int64_t [size](#size) | Size of the data source. | 23| [OH_AVDataSourceReadAt](_codec_base.md#oh_avdatasourcereadat) [readAt](#readat) | Callback of the data source. | 24 25 26## Member Variable Description 27 28 29### readAt 30 31``` 32OH_AVDataSourceReadAt OH_AVDataSource::readAt 33``` 34 35**Description** 36 37Callback of the data source. 38 39**System capability**: SystemCapability.Multimedia.Media.CodecBase 40 41**Since**: 12 42 43 44### size 45 46``` 47int64_t OH_AVDataSource::size 48``` 49 50**Description** 51 52Size of the data source. 53 54**System capability**: SystemCapability.Multimedia.Media.CodecBase 55 56**Since**: 12 57