在android下移植了png库，实现在ndk层将一个BMP位图转换为PNG位图。java层代码仅做示例，ndk代码可以直接使用-Ported the android png library, a BMP bitmap in ndk layer will be converted to PNG bitmap. layer java code only as example, the the ndk code can be used directly

本开源Android播放器基于ffmpeg开发，音视频在jni层直接输出，不使用java层的bmp和audiotrack输出，支持arm汇编加速，超级精简。-The open source Android player based on ffmpeg development, audio and video in the direct output of the jni layer, do not use bmp and audiotrack output, of the java layer