Is it possible to code interlaced video with MPEG-1 syntax?
A. Two methods can be applied to interlaced video that maintain syntactic compatibility with MPEG-1 (which was originally designed for progressive frames only). In the field concatenation method, the encoder model can carefully construct predictions and prediction errors that realize good compression but maintain field integrity (distinction between adjacent fields of opposite parity). Some pre-processing techniques can also be applied to the interlaced source video that would, e.g., lessen sharp vertical frequencies. This technique is not terribly efficient of course. On the other hand, if the original source was progressive (e.g. film), then it is more trivial to convert the interlaced source to a progressive format before encoding. (MPEG-2 would then only offer slightly superior performance through such MPEG-2 enhancements as greater DC coefficient precision, non-linear mquant, intra VLC, etc.) Reconstructed frames are usually re-interlaced in the Display process following the decod
