AVHWFramesContext主要表示硬件Frame的一些参数#xff0c;比如你解码后的YUV数据还在硬件上#…HWContextType算是ffmpeg中为硬解码第三方接口的一个辅助类它自己有两个辅助子类

AVHWDeviceContext和AVHWFramesContext。

AVHWFramesContext主要表示硬件Frame的一些参数比如你解码后的YUV数据还在硬件上那么就通过这个类去存储相关参数。

const

sizeof(AVCUDADeviceContext),.frames_priv_size

sizeof(CUDAFramesContext),.device_create

cuda_device_create,.device_derive

cuda_device_derive,.device_init

cuda_device_init,.device_uninit

cuda_device_uninit,.frames_get_constraints

cuda_frames_get_constraints,.frames_init

cuda_frames_init,.frames_get_buffer

cuda_get_buffer,.transfer_get_formats

cuda_transfer_get_formats,.transfer_data_to

cuda_transfer_data,.transfer_data_from

(const

mem操作大白话说就是ffmpeg通过这套机制来实现D2H或者H2D的操作别无其它。

具体看看结构体定义吧一大堆函数指针这些就是你要实现的不一定全部要实现实现你自己想要的就可以了主要的有transfer_data_to/transfer_data_frommap_to/map_from。

typedef

AVHWDeviceContext.hwctx*/size_t

size

AVHWDeviceInternal.priv*/size_t

Size

AVHWFramesContext.hwctx*/size_t

size

AVHWFramesInternal.priv*/size_t

frames_priv_size;int

(*device_create)(AVHWDeviceContext

*ctx,

(*device_derive)(AVHWDeviceContext

*opts,

(*device_init)(AVHWDeviceContext

*ctx);void

(*device_uninit)(AVHWDeviceContext

*ctx);int

(*frames_get_constraints)(AVHWDeviceContext

*ctx,const

*hwconfig,AVHWFramesConstraints

*constraints);int

(*frames_init)(AVHWFramesContext

*ctx);void

(*frames_uninit)(AVHWFramesContext

*ctx);int

(*frames_get_buffer)(AVHWFramesContext

*ctx,

(*transfer_get_formats)(AVHWFramesContext

*ctx,enum

(*transfer_data_to)(AVHWFramesContext

*ctx,

(*transfer_data_from)(AVHWFramesContext

*ctx,

(*frames_derive_to)(AVHWFramesContext

*src_ctx,

(*frames_derive_from)(AVHWFramesContext

*src_ctx,

HWContextType;AVHWFramesContext结构体表示

/***

av_hwframe_ctx_init().*/AVHWDeviceContext

*device_ctx;/***

AVHWFramesContext;AVHWDeviceContext的结构体表示硬件的抽象

/***

av_hwdevice_ctx_alloc().*/const

AVClass

这些函数其实挺重要的因为都是用户函数通过这些函数去从解码器硬件上获取到你要的数据比如av_hwframe_transfer_data/av_hwframe_get_buffer就是说你在ffmpeg中不要显示的调用你自己的cuMemD2H或者H2D的函数ffmpeg已经给你预留好了接口了用这些接口去获取更加简单。

/***

av_hwdevice_find_type_by_name(const

char

*av_hwdevice_get_type_name(enum

AVHWDeviceType

av_hwdevice_ctx_init(AVBufferRef

*ref);/***

av_hwdevice_ctx_alloc()/av_hwdevice_ctx_init().**

The

av_hwdevice_ctx_create(AVBufferRef

**device_ctx,

av_hwdevice_ctx_create_derived(AVBufferRef

**dst_ctx,enum

av_hwdevice_ctx_create_derived,*

however,

av_hwdevice_ctx_create_derived_opts(AVBufferRef

**dst_ctx,enum

*av_hwframe_ctx_alloc(AVBufferRef

*device_ctx);/***

av_hwframe_ctx_init(AVBufferRef

*ref);/***

av_hwframe_get_buffer(AVBufferRef

*hwframe_ctx,

av_hwframe_transfer_get_formats(src,*

AV_HWFRAME_TRANSFER_DIRECTION_FROM).*

dst

av_hwframe_transfer_get_formats(dst,*

AV_HWFRAME_TRANSFER_DIRECTION_TO)**

dst

AVHWFramesContext.width/height),

since

av_hwframe_transfer_data(AVFrame

*dst,

frame.*/AV_HWFRAME_TRANSFER_DIRECTION_FROM,/***

Transfer

frame.*/AV_HWFRAME_TRANSFER_DIRECTION_TO,

};/***

av_hwframe_transfer_get_formats(AVBufferRef

*hwframe_ctx,enum