Claims
- 1. An encoding system, for encoding a digital information signal having a first signal component and a second signal component, comprising
- subband coding means for generating (a) a first subband signal in response to the first signal component, the first subband signal including a first signal block of q samples of the first subband signal, where q is a positive integer, and (b) a second subband signal in response to the second signal component, the second subband signal including a second signal block of q samples of the second subband signal, the first and the second subband signals being in a same subband and the first and second signal blocks being time-equivalent; and
- quantizing means for quantizing said samples in said first and second signal blocks to form first and second quantized signal blocks, said samples in said first and second quantized signal blocks being represented by n.sub.m1 and n.sub.m2 bits respectively, and
- said quantizing means comprises:
- bit need means for determining a respective bit need b for said first signal block and a respective bit need b for said second signal block, said respective bit need for the first signal block being related to the number of bits by which the samples in said first signal block should be represented, and said respective bit need for the second signal block being related to the number of bits by which the samples in said second signal block should be represented,
- bit allocation means, responsive to the respective bit needs b for said first signal block and for said second signal block determined in the bit need means, for allocating a portion of an available quantity of bits to said samples in said first and second signal blocks to obtain the values n.sub.m1 and n.sub.m2 for the corresponding quantized first and second signal blocks,
- determining means for determining, for one block of said first and second signal blocks, whether an initial allocation of bits to the samples in said one block is to be performed in the bit allocation means irrespective of the respective bit need b of said one block determined by said bit need means; and
- means for producing a first control signal responsive to the determination by said determining means,
- said bit allocation means being responsive to said first control signal, for initially allocating a first number of bits to the samples of said one block, and for initially allocating a second number of bits to the samples of the other block of said first and second signal blocks, irrespective of the respective bit need b of said other block determined by said bit need means.
- 2. A system as claimed in claim 1, characterized in that said first and said second numbers are the same.
- 3. A system as claimed in claim 1, characterized in that said determining means evaluates each of said signal blocks to determine if said initial allocation is to be performed for at least one of said signal blocks, and
- said means for producing produces said first control signal if said initial allocation is to be performed for at least one of said signal blocks.
- 4. A system as claimed in claim 3, characterized in that said determining means comprises means for determining, for said other block, whether no bit allocation to the samples in said other block should be allocated in the bit allocation means, and
- means for producing a second control signal in response to said determining means determining that, for each of said first and second signal blocks, no initial allocation is to be performed, and that no bit allocation to the samples in said other block should be allocated in the bit allocation means, and
- said bit allocation means comprises means, responsive to said second control signal, for allocating no bits to said other block.
- 5. A system as claimed in claim 3, characterized in that said determining means comprises first means for determining, for said one block, whether no bit allocation to the samples in said one block need be allocated in the bit allocation means; and second means for determining, for said other block, whether no bit allocation to the samples in said other block need be allocated in the bit allocation means, and
- means, responsive solely to said first and second means each determining, for the respective one and other blocks, that no bit allocation need be performed, for producing a second control signal, and
- said bit allocation means comprises means, responsive to said second control signal, for allocating no bits to either of said first and second signal blocks.
- 6. An encoding system comprising a subband coder for subband digital coding of an information signal constituted by at least first and second signal components, said subband coder including:
- signal splitting means, responsive to said information signal, for splitting said information signal into M successive subbands and generating digital subband signals comprising a succession of signal blocks, in a subband SB.sub.m a succession of first and second corresponding time-equivalent signal blocks respectively containing samples of first and second subband signal components related to said first and second signal components, and
- quantizing means for quantizing block-by-block said samples of first and second subband signal components in the subband SB.sub.m to form quantized signal blocks, said samples in one pair of corresponding quantized signal blocks in said subband SB.sub.m being represented by n.sub.m1 and n.sub.m2 bits respectively,
- said quantizing means comprising:
- bit need means for determining a respective bit need b for respective signal blocks in the M subbands, said respective bit need being related to the number of bits by which said samples in said signal blocks in respective ones of the M subbands should be represented,
- bit allocation means, responsive to the bit needs determined in the bit need means, for allocating an available quantity of bits to respective samples in the different signal blocks in the M subbands,
- determining means for determining, for one signal block of said pair, whether an initial allocation of bits to the samples in said one signal block is to be performed in the bit allocation means irrespective of the bit need of said one signal block determined by said bit need means; and
- means for producing a first SB.sub.m control signal responsive to the determination by said determining means,
- said bit allocation means being responsive to said first SB.sub.m control signal, for initially allocating a first number of bits to the samples of said one signal block, and for initially allocating a second number of bits to the samples of the other block of said pair irrespective of the bit need of said other block determined by said bit need means.
- 7. A system as claimed in claim 6, wherein said first number and said second number are the same.
- 8. A system as claimed in claim 7, characterized in that said determining means evaluates each signal block of said pair to determine if said initial allocation is to be performed for one of said signal blocks of said pair,
- said means for producing produces said first SB.sub.m control signal if said initial allocation is to be performed for said one signal block of said pair,
- said determining means further comprises means for determining, for the other signal block of said pair, that no bit allocation to the samples in said other signal block should be allocated in the bit allocation means, and
- means for producing a second SB.sub.m control signal in response to said determining means determining that, for each signal block of said pair, no initial allocation is to be performed, and that, for said other signal block, no bit allocation to the samples in that signal block should be allocated in the bit allocation means, and
- said bit allocation means comprises means, responsive to said second SB.sub.m control signal, for allocating no bits to said other signal block irrespective of the bit need of said other signal block.
- 9. A system as claimed in claim 7, characterized in that said determining means evaluates each signal block of said pair to determine if said initial allocation is to be performed for at least one of said signal blocks of said pair, and
- said means for producing produces said first SB.sub.m control signal if said initial allocation is to be performed for at least one signal block of said pair.
- 10. A system as claimed in claim 9, characterized in that said determining means comprises first means for determining, for said one signal block of said pair, that no bit allocation to the samples in said one signal block need be allocated in the bit allocation means; and second means for determining, for the other signal block of said pair, that no bit allocation to the samples in said other signal block need be allocated in the bit allocation means,
- means for producing a second SB.sub.m control signal, responsive solely to said first and second means each determining, for the respective block of said pair, that no initial allocation is to be performed, and
- said bit allocation means comprises means, responsive to said second SB.sub.m, control signal, for allocating no bits to either signal block of said pair irrespective of the bit need of either signal block
- 11. An encoding system comprising a subband coder for subband digital coding, including coding in an intensity mode, of an information signal constituted by at least first and second signal components, including:
- signal splitting means, responsive to said information signal, for splitting said information signal into M successive subbands and generating digital subband signals comprising a succession of signal blocks, in a subband SB.sub.m a succession of first and second corresponding time-equivalent signal blocks respectively containing samples of first and second subband signal components related to said first and second signal components,
- means for combining corresponding samples of the first and second subband signal components of a subband SB.sub.p, where p.noteq.m, to obtain a combined subband signal, and quantizing the combined subband signal to provide a quantized combined subband signal constituted by combined signal blocks each containing q samples, the q samples in a combined signal block of the quantized combined subband signal each being represented by n.sub.pc bits, and
- quantizing means for quantizing block-by-block the samples of first and second subband signal components in the subband SB.sub.m to form component signal blocks, the samples in a pair of corresponding component signal blocks of the first and second quantized subband signal components in said subband SB.sub.m being represented by n.sub.m1 and n.sub.m2 bits respectively,
- wherein said quantizing means comprises:
- bit need means for determining a respective bit need b for respective signal blocks in the subbands, said bit need being related to the number of bits by which the samples in a signal block in a respective subband should be represented,
- bit allocation means, responsive to the bit needs determined in the bit need determining means, for allocating an available quantity of bits to respective samples in the different signal blocks in the M subbands, and
- determining means for determining, for a particular signal block of the first subband signal component in the subband SB.sub.m, whether an initial allocation of a number of bits to the samples in said particular signal block is to be performed in the bit allocation means irrespective of the bit need b of particular signal block determined by said bit need means,
- and wherein:
- for the subband SB.sub.p, said determining means evaluates each signal block of an SB.sub.p pair of corresponding time-equivalent signal blocks prior to combining of the corresponding samples, and said means for producing produces a first SB.sub.p control signal if said initial allocation is to be performed for one signal block of said SB.sub.p pair,
- said means for combining and quantizing then combines corresponding samples of the first and second subband signal components in the subband SB.sub.p to obtain said combined subband signal which is then quantized, and
- said bit allocation means, responsive to said first SB.sub.p control signal, initially allocates a third number of bits to the samples of said combined subband signal.
- 12. A system as claimed in claim 11, characterized in that for subband SB.sub.p said determining means comprises first means for determining, for said one signal block of said SB.sub.p pair, that no bit allocation to the samples in said one signal block need be allocated in the bit allocation means; and second means for determining, for the other signal block of said SB.sub.p pair, that no bit allocation to the samples in said other signal block need be allocated in the bit allocation means,
- means for producing a second SB.sub.p control signal, responsive solely to said first and second means each determining, for the respective signal block of said SB.sub.p pair, that no initial allocation is to be performed, and
- said bit allocation means comprises means, responsive to said second SB.sub.p control signal, for allocating no bits for quantizing the combined subband signal for said SB.sub.p pair.
Priority Claims (1)
Number |
Date |
Country |
Kind |
91202221 |
Sep 1991 |
EPX |
|
Parent Case Info
This is a continuation of application Ser. No. 07/841,917, filed Feb. 25, 1992, abandoned.
US Referenced Citations (10)
Non-Patent Literature Citations (1)
Entry |
IEEE ICASSP 80, vol. 1, 327-331, Apr. 9-11, 1980, M. A. Krasner "The Critical Band Coder . . . Digital Encoding of Speech Signals Based on the Perceptual Requirements of the Auditory System". |
Continuations (1)
|
Number |
Date |
Country |
Parent |
841917 |
Feb 1992 |
|