That MC50 in the video has a CMOS scanner and should not be used for scanning instensive applications. The barcodes that did not scan appear to be CODE39. The MC50 can scan them but it appears that the length is the contributing factor. The MC50 with the Digital imager would work better.
mc50s are not worth the money it seems. It is hard to find them with 1 and 2d scanners. The mc35 is a much better buy. The mc75 is by far my favorite.