在MediaCodec里面可以看到 Configure 和 SetSurface 都是接收一个 sp<Surface> 入参的，而回归到 NDK 侧，则可以发现，传递给 AMediaCodec_Configure 和 AMediaCodec_SetSurface 的确是 ANativeWindow 指针，因此 ndk 里面必然进行了某种转换。
EXPORT
media_status_t AMediaCodec_configure(AMediaCodec *mData,const AMediaFormat* format,ANativeWindow* window,AMediaCrypto *crypto,uint32_t flags) {sp<AMessage> nativeFormat;AMediaFormat_getFormat(format, &nativeFormat);// create our shallow copy, so we aren't victim to any later changes.sp<AMessage> dupNativeFormat = nativeFormat->dup();ALOGV("configure with format: %s", dupNativeFormat->debugString(0).c_str());sp<Surface> surface = NULL;if (window != NULL) {surface = (Surface*) window;}status_t err = mData->mCodec->configure(dupNativeFormat, surface,crypto ? crypto->mCrypto : NULL, flags);if (err != OK) {ALOGE("configure: err(%d), failed with format: %s",err, dupNativeFormat->debugString(0).c_str());}return translate_error(err);
}//prebuilts/vndk/v32/arm64/include/frameworks/native/libs/gui/include/gui/Surface.h/** An implementation of ANativeWindow that feeds graphics buffers into a* BufferQueue.** This is typically used by programs that want to render frames through* some means (maybe OpenGL, a software renderer, or a hardware decoder)* and have the frames they create forwarded to SurfaceFlinger for* compositing. For example, a video decoder could render a frame and call* eglSwapBuffers(), which invokes ANativeWindow callbacks defined by* Surface. Surface then forwards the buffers through Binder IPC* to the BufferQueue's producer interface, providing the new frame to a* consumer such as GLConsumer.*/
class Surface: public ANativeObjectBase<ANativeWindow, Surface, RefBase>由此可见， Surface 类是 ANativeWindow 的子类。
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