1# PreviewOutput_Callbacks 2 3 4## Overview 5 6The **PreviewOutput_Callbacks** struct defines the callbacks used for preview output. 7 8**See** 9 10[OH_PreviewOutput_RegisterCallback](_o_h___camera.md#oh_previewoutput_registercallback) 11 12**Since**: 11 13 14**Related module**: [OH_Camera](_o_h___camera.md) 15 16 17## Summary 18 19 20### Member Variables 21 22| Name| Description| 23| -------- | -------- | 24| [onFrameStart](#onframestart) | Callback to report preview output frame start events.| 25| [onFrameEnd](#onframeend) | Callback to report preview output frame end events.| 26| [onError](#onerror) | Callback to report preview output errors.| 27 28 29## Member Variable Description 30 31 32### onError 33 34``` 35OH_PreviewOutput_OnError PreviewOutput_Callbacks::onError 36``` 37 38**Description** 39 40Callback to report preview output errors. 41 42 43### onFrameEnd 44 45``` 46OH_PreviewOutput_OnFrameEnd PreviewOutput_Callbacks::onFrameEnd 47``` 48 49**Description** 50 51Callback to report preview output frame end events. 52 53 54### onFrameStart 55 56``` 57OH_PreviewOutput_OnFrameStart PreviewOutput_Callbacks::onFrameStart 58``` 59 60**Description** 61 62Callback to report preview output frame start events. 63