This program is part of Netpbm.
yuvtoppm reads raw Abekas YUV bytes as input and produces a PPM image as output. The input file is just YUV bytes. You have to specify the width and height on the command line, since the program obviously can't get them from the file. yuvotppm assumes the maxval of the input is 255.
The ppmtoyuv manual tells a little about the Abekas YUV format.
Copyright (C) 1991 by DHD PostImage Inc.
Copyright (C) 1987 by Abekas Video Systems Inc.