1# OH_AVCodecCallback 2 3 4## Overview 5 6The **OH_AVCodecCallback** struct defines all the asynchronous callback function pointers of an **OH_AVCodec** instance. To ensure the normal running of **OH_AVCodec**, you must register the instance of this struct with the **OH_AVCodec** instance and process the information reported by the callback function. 7 8For details about the development guide, see step 4 in surface mode or step 3 in buffer mode in [Video Encoding](../../media/avcodec/video-encoding.md). 9 10**System capability**: SystemCapability.Multimedia.Media.CodecBase 11 12**Since**: 11 13 14**Related module**: [CodecBase](_codec_base.md) 15 16**Header file**: [native_avcodec_base.h](native__avcodec__base_8h.md) 17 18 19## Summary 20 21 22### Member Variables 23 24| Name| Description| 25| -------- | -------- | 26| [OH_AVCodecOnError](_codec_base.md#oh_avcodeconerror) [onError](#onerror) | Defines the callback used to report a codec operation error.| 27| [OH_AVCodecOnStreamChanged](_codec_base.md#oh_avcodeconstreamchanged) [onStreamChanged](#onstreamchanged) | Defines the callback used to report a codec stream change.| 28| [OH_AVCodecOnNeedInputBuffer](_codec_base.md#oh_avcodeconneedinputbuffer) [onNeedInputBuffer](#onneedinputbuffer) | Defines the callback used to report input data required.| 29| [OH_AVCodecOnNewOutputBuffer](_codec_base.md#oh_avcodeconnewoutputbuffer) [onNewOutputBuffer](#onnewoutputbuffer) | Defines the callback used to report output data generated.| 30 31 32## Member Variable Description 33 34 35### onError 36 37**Description** 38 39Defines the callback used to report a codec operation error. 40 41**Since**: 11 42 43 44### onNeedInputBuffer 45 46**Description** 47 48Defines the callback used to report input data required. 49 50**Since**: 11 51 52 53### onNewOutputBuffer 54 55**Description** 56 57Defines the callback used to report output data generated. 58 59**Since**: 11 60 61 62### onStreamChanged 63 64**Description** 65 66Defines the callback used to report a codec stream change. 67 68**Since**: 11 69