- Mpeg2PicHdr *fh
- Previously allocated and initialized Mpeg2PicHdr structure.
- Indicates whether to retrieve forward fcodes or backward fcodes. 0 indicates forward, 1 indicates backward.
- Indicates whether to retrieve horizontal fcodes or vertical fcodes. 0 indicates horizontal, 1 indicates vertical.
1 or 4 fcode values governing decoding of motion vectors.
Returns 1 of 4 fcode values which are used to govern how many bits are used to encode motion vectors. The four fcodes correspond to four different types of motion vectors (forw/bwd crossed with horiz/vert). The back_flag and vert_flag parameters are used to select which one is to be returned.