ff_png_zfree       69 libavcodec/png.h void ff_png_zfree(void *opaque, void *ptr);
ff_png_zfree      404 libavcodec/pngdec.c     s->zstream.zfree = ff_png_zfree;
ff_png_zfree      282 libavcodec/pngenc.c     s->zstream.zfree = ff_png_zfree;