Y4M_FRAME_MAGIC   308 libavformat/yuv4mpegdec.c     if (strncmp(header, Y4M_FRAME_MAGIC, strlen(Y4M_FRAME_MAGIC)))
Y4M_FRAME_MAGIC   207 libavformat/yuv4mpegenc.c     avio_printf(s->pb, "%s\n", Y4M_FRAME_MAGIC);