Signal processing method and device and video system

A signal processing device for performing inverse orthogonal transform for a combination of orthogonal transform coefficients obtained by orthogonal-transforming a signal, the device comprising:

• a storage section for storing in advance a signal value obtained by performing inverse orthogonal transform for at least one predetermined combination of orthogonal transform coefficients;
• a determination section for receiving combinations of orthogonal transform coefficients sequentially and determining whether or not each of the received combinations of orthogonal transform coefficients corresponds with the predetermined combination of orthogonal transform coefficients for which the signal value is stored in advance;
• and
• a processing section for performing first inverse orthogonal transform in which a restored signal is output based on the signal value stored in advance if the received combination of orthogonal transform coefficients corresponds with the predetermined combination of orthogonal transform coefficients as a result of the determination by the determination section, and performing second inverse orthogonal transform in which the received combination of orthogonal transform coefficients is subjected to inverse orthogonal transform by computation if the received combination of orthogonal transform coefficients does not correspond with the predetermined combination of orthogonal transform coefficients.

A signal processing device for performing inverse orthogonal transform for a predetermined combination of orthogonal transform coefficients obtained by orthogonal-transforming a signal, the device comprising:

• a storage section for storing in advance a signal value obtained by performing inverse orthogonal transform for at least one predetermined combination of orthogonal transform coefficients;
• an index generation section for grouping a plurality of received combinations of orthogonal transform coefficients, determining whether or not a signal value corresponding to each group is stored in advance in the storage section, and if the signal value is stored in the storage section, generating a flag as well as supplying an index for specifying the signal value for the corresponding group to the storage section to enable output of the signal value for the corresponding group from the storage section;
• a signal output section for receiving the signal value output from the storage section and sequentially outputting a plurality of signal values constituting a restored signal based on the signal value;
• an inverse orthogonal transform section for performing inverse orthogonal transform for the received combination of the orthogonal transform coefficients by computation;
• and
• a selection section for selecting the signal values from the signal output section if the index generation section generates a flag, and selecting the output from the inverse orthogonal transform section if no flag is generated,
• wherein inverse orthogonal transform for a received combination of orthogonal transform coefficients is switched between first inverse orthogonal transform of outputting a restored signal based on the signal value stored in advance and second inverse orthogonal transform performed by computation.