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;