我直接利用ffmpeg的libavcodec和libavutil静态库编出了bpg decoder，不过解码时有点问题
应该是bpg作者设计时删去了sps等信息，求教如何把这些东西重建起来？

HEVC bit stream: the standard HEVC headers (the VPS and SPS NALs)
give an overhead of about 60 bytes for no added value in the case of
picture compression. Since the alpha plane uses a different HEVC bit
stream, it also adds the same overhead again. So we removed the VPS
and SPS NALs and added a very small header with the equivalent
information (typically 4 bytes). We also removed the first NAL start
code which is not useful. It is still possible to reconstruct a
standard HEVC stream to feed an unmodified hardware decoder if needed.
作者是这样说的，但也没搞个reconstruct的程序，略坑啊。

我编译的bpg及源码[无效] http://pan.baidu.com/s/1jG6BygY

想方法对比一下自己编译的编码器生成的bpg和官方程序生成的bpg.
要么就是对比下解析first NAL的代码.