作者你好，请教个ijkplayer提交说明

ijkplayer 7ab0abe5提交中说遇到了codec随机crash问题，并增加了如下一句修改处理，
SDL_VoutAndroid_setAMediaCodec(opaque->weak_vout, NULL);
但这句处理中，invalidateAllBuffers在stop操作前已做处理，decreaseReferenceP acodec处理在
新增加的补丁前已做处理，所以不明白加的patch是如何生效的？

另外提交说明说到，问题原因是在创建新的mediacodec前，没有先release 上次的mediacodec，
而在加这个patch前已经有做先release mediacodec，然后new mediacodec， 所以对这个修改
有点疑惑，望帮忙指明，十分感谢，期待您的回复，谢谢。

详细提交内容见下:

7ab0abe5e3dcb60b1942b0a7a7a4cc2daff21867
Fix reconfigure codec randomly crash.
ijkplayer used to stop previous mediacodec & create a new mediacodec, then release previous.

background knowledge:
vendor vdec drv init, checking codec & alloc framebuffer to hw, the framebuffer will returned to memmap until call the deinit.

in android native mediacodec impl:
mediacodec stop do not deinit omx component(just changed omx state to idle), continues create a new mediacodec would lead some vendor drv notify err(ex :InsufficientResources) due to memory is not enough or vendor hw limitation(one instance).

this case is not appeared in android mediaplayer becoz nuplayer would release previous mediacodec then create a new one.
solution: release previous mediacodec then create a new one when reconfigure codec.