# PreviewOutput_Callbacks ## Overview The PreviewOutput_Callbacks struct describes the callbacks related to preview output. For details, see [OH_PreviewOutput_RegisterCallback](_o_h___camera.md#oh_previewoutput_registercallback). **Since**: 11 **Related module**: [OH_Camera](_o_h___camera.md) ## Summary ### Member Variables | Name| Description| | -------- | -------- | | [OH_PreviewOutput_OnFrameStart](_o_h___camera.md#oh_previewoutput_onframestart) [onFrameStart](#onframestart) | Callback to report preview output frame start events.| | [OH_PreviewOutput_OnFrameEnd](_o_h___camera.md#oh_previewoutput_onframeend) [onFrameEnd](#onframeend) | Callback to report preview output frame end events.| | [OH_PreviewOutput_OnError](_o_h___camera.md#oh_previewoutput_onerror) [onError](#onerror) | Callback to report preview output errors.| ## Member Variable Description ### onError ``` OH_PreviewOutput_OnError PreviewOutput_Callbacks::onError ``` **Description** Callback to report preview output errors. ### onFrameEnd ``` OH_PreviewOutput_OnFrameEnd PreviewOutput_Callbacks::onFrameEnd ``` **Description** Callback to report preview output frame end events. ### onFrameStart ``` OH_PreviewOutput_OnFrameStart PreviewOutput_Callbacks::onFrameStart ``` **Description** Callback to report preview output frame start events.