Graceful degradation and scalability in digital coding for terrestrial transmission

Hierarchical coding of TV and HDTV for terrestrial transmission is described. A frequency scalable coding system currently studied within the MPEG is appropriate for achieving high coding efficiency and quality in all layers. Both scalability and graceful degradation are very challenging features in a future terrestrial distribution service for digital video. These two major requirements are strongly related and, thus, can be solved with the same coding concept. The frequency scalable approach, i.e., the link between the layers is performed in the DCT domain (DCT or frequency scalability) and not in the spatial domain (spatial scalability), can be combined with frequency scanning methods to achieve a very robust source coding system.