Y4M_FRAME_MAGIC   284 libavformat/yuv4mpegdec.c     if (strncmp(header, Y4M_FRAME_MAGIC, strlen(Y4M_FRAME_MAGIC)))
Y4M_FRAME_MAGIC   166 libavformat/yuv4mpegenc.c     snprintf(buf1, sizeof(buf1), "%s\n", Y4M_FRAME_MAGIC);