Our implementations are meant for research, not production use, and as such are somewhat limited. A brief list of the important features and limitations follows. In deciding which features to include and which to leave out, we followed the general rule that features aiding in video compression (such as skipping low-noise macroblocks in motion predicted images) are always included and tested. Features which simply provide a greater breadth of video formats, (i.e. support for both interlaced and progressive video) were limited to a small working subset.
Features of the Encoder and Decoder:
Our decoder does not enforce profile/level restrictions. (For instance, if the bitstream low_delay value indicates that the bitstream cannot contain B pictures, the decoder will not enforce this.) As such, it is possible that certain invalid MPEG-2 bitstreams would decode without generating an error message.