Device and method for quantizing and inverse quantizing LPC filters in a super-frame

A method for quantizing LPC filters in a super-frame including a sequence of a first frame during which a filter LPC1 is calculated, a second frame during which a filter LPC2 is calculated, a third frame during which a filter LPC3 is calculated, and a fourth frame during which a filter LPC4 is calculated, the LPC filter quantizing method comprising:

• quantizing the filter LPC4 using absolute quantization;
• quantizing the filter LPC2 using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC4;
• quantizing the filter LPC1 using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC2;
• and
• quantizing the filter LPC3 using a quantization mode selected from the group consisting of absolute quantization, differential quantization relative to the quantized filter LPC2, differential quantization relative to the quantized filter LPC4, and differential quantization relative to both the quantized filters LPC2 and LPC4.

A method for quantizing LPC filters in a super-frame including a sequence of a first frame during which a filter LPC1 is calculated, a second frame during which a filter LPC2 is calculated, a third frame during which a filter LPC3 is calculated, and a fourth frame during which a filter LPC4 is calculated, the LPC filter quantizing method comprising:

• quantizing the filter LPC4 using absolute quantization;
• quantizing the filter LPC2 using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC4;
• quantizing the filter LPC1 using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC2;
• and
• quantizing the filter LPC3 using a quantization mode selected from the group consisting of absolute quantization, differential quantization relative to the quantized filter LPC2, differential quantization relative to the filter quantized LPC4, and differential quantization relative to both the quantized filters LPC2 and LPC4;
• wherein the method further comprises quantizing a filter LPC0 corresponding to a last LPC filter calculated during a previous super-frame, wherein quantizing the filter LPC1 comprises using a quantization mode selected from the group consisting of absolute quantization, differential quantization relative to the quantized filter LPC2, and differential quantization relative to both the quantized filters LPC0 and LPC2.

A device for quantizing LPC filters in a super-frame including a sequence of a first frame during which a filter LPC1 is calculated, a second frame during which a filter LPC2 is calculated, a third frame during which a filter LPC3 is calculated, and a fourth frame during which a filter LPC4 is calculated, the LPC filter quantizing device comprising:

• a quantizer of the filter LPC4 using absolute quantization;
• a quantizer of the filter LPC2 using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC4;
• a quantizer of the filter LPC1 using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC2;
• and
• a quantizer of the filter LPC3 using a quantization mode selected from the group consisting of absolute quantization, differential quantization relative to the quantized filter LPC2, differential quantization relative to the quantized filter LPC4, and differential quantization relative to both the quantized filters LPC2 and LPC4.

A device for quantizing LPC filters in a super-frame including a sequence of a first frame during which a filter LPC1 is calculated, a second frame during which a filter LPC2 is calculated, a third frame during which a filter LPC3 is calculated, and a fourth frame during which a filter LPC4 is calculated, the LPC filter quantizing device comprising:

• a quantizer of the filter LPC4 using absolute quantization;
• a quantizer of the filter LPC2 using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC4;
• a quantizer of the filter LPC1 using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC2;
• and
• a quantizer of the filter LPC3 using a quantization mode selected from the group consisting of absolute quantization, differential quantization relative to the quantized filter LPC2, differential quantization relative to the quantized filter LPC4, and differential quantization relative to both the quantized filters LPC2 and LPC4;
• wherein the device further comprises a quantizer of a filter LPC0 corresponding to a last LPC filter calculated during a previous super-frame, wherein the quantizer of the filter LPC1 uses a quantization mode selected from the group consisting of absolute quantization, differential quantization relative to the quantized filter LPC2, and differential quantization relative to both the quantized filters LPC0 and LPC2.

A method for inverse quantizing at least one LPC filter in a super-frame including a sequence of frames each associated to a LPC filter, wherein one of the LPC filters is first quantized using absolute quantization and the other LPC filters are subsequently quantized using a quantization process providing, for each of the other LPC filters, a choice of an absolute quantization and of a differential quantization relative to at least one previously quantized filter amongst the LPC filters, and wherein the method for inverse quantizing the at least one LPC filter comprises:

• receiving at least the first quantized LPC filter;
• inverse quantizing the first quantized LPC filter using absolute inverse quantization;
• and
• if any quantized LPC filter other than the first quantized LPC filter is received, inverse quantizing said quantized LPC filter according to the choice of absolute inverse quantization and of differential inverse quantization relative to at least one previously received quantized LPC.

A method for inverse quantizing at least one LPC filter in a super-frame including a sequence of a first frame associated to a filter LPC1, a second frame associated to a filter LPC2, a third frame associated to a filter LPC3, and a fourth frame associated to a filter LPC4, wherein the filter LPC4 is first quantized using absolute quantization, the filter LPC2 is quantized using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC4, the filter LPC1 is quantized using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC2, and the filter LPC3 is quantized using a quantization mode selected from the group consisting of absolute quantization, differential quantization relative to the quantized filter LPC2, differential quantization relative to the quantized filter LPC4, and differential quantization relative to both the quantized filters LPC2 and LPC4, wherein the super-frame is coded using a set of coding modes including at least one first coding mode covering a duration of one frame, a second coding mode covering a duration of two frames, and a third coding mode covering a duration of four frames, and wherein the method for inverse quantizing the at least one LPC filter comprises:

• receiving the first quantized filter LPC4;
• if the first, second, third and fourth frames of the super-frame are not coded using the third coding mode, receiving the quantized filter LPC2 and a first index indicative of one of the absolute quantization mode and the differential quantization mode;
• if the first and second frames of the super-frame are coded using the at least one first coding mode, receiving the quantized filter LPC1 and a second index indicative of one of the absolute quantization mode and the differential quantization mode;
• if the third and fourth frames of the super-frame are coded using the at least one first coding mode, receiving the quantized filter LPC3 and a third index indicative of one of the absolute quantization mode and the differential quantization mode;
• inverse quantizing the first quantized LPC filter using absolute inverse quantization;
• if the quantized filter LPC2 is received, inverse quantizing the filter LPC2 using, as indicated by the first index, one of absolute inverse quantization and differential inverse quantization relative to the quantized filter LPC4;
• if the quantized filter LPC1 is received, inverse quantizing the filter LPC1 using, as indicated by the second index, one of absolute inverse quantization and differential inverse quantization relative to the quantized filter LPC2;
• and
• if the quantized filter LPC3 is received, inverse quantizing the filter LPC3 using, as indicated by the third index, one of absolute inverse quantization, differential inverse quantization relative to the quantized filter LPC2, differential inverse quantization relative to the quantized filter LPC4, and differential inverse quantization relative to both the quantized filters LPC2 and LPC4.

A method for inverse quantizing at least one LPC filter in a super-frame including a sequence of a first frame associated to a filter LPC1, a second frame associated to a filter LPC2, a third frame associated to a filter LPC3, and a fourth frame associated to a filter LPC4, wherein the filter LPC4 is first quantized using absolute quantization, the filter LPC2 is quantized using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC4, the filter LPC1 is quantized using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC2, and the filter LPC3 is quantized using a quantization mode selected from the group consisting of absolute quantization, differential quantization relative to the quantized filter LPC2, differential quantization relative to the quantized filter LPC4, and differential quantization relative to both the quantized filters LPC2 and LPC4, wherein the super-frame is coded using a set of coding modes including at least one first coding mode covering a duration of one frame, a second coding mode covering a duration of two frames, and a third coding mode covering a duration of four frames, and wherein the method for inverse quantizing the at least one LPC filter comprises:

• receiving the first quantized filter LPC4;
• if the first, second, third and fourth frames of the super-frame are not coded using the third coding mode, receiving the quantized filter LPC2 and a first index indicative of one of the absolute quantization mode and the differential quantization mode;
• if the first and second frames of the super-frame are coded using the at least one first coding mode, receiving the quantized filter LPC1 and a second index indicative of one of the absolute quantization mode and the differential quantization mode;
• if the third and fourth frames of the super-frame are coded using the at least one first coding mode, receiving the quantized filter LPC3 and a third index indicative of one of the absolute quantization mode and the differential quantization mode;
• inverse quantizing the first quantized LPC filter using absolute inverse quantization;
• if the quantized filter LPC2 is received, inverse quantizing the filter LPC2 using, as indicated by the first index, one of absolute inverse quantization and differential inverse quantization relative to the quantized filter LPC4;
• if the quantized filter LPC1 is received, inverse quantizing the filter LPC1 using, as indicated by the second index, one of absolute inverse quantization and differential inverse quantization relative to the quantized filter LPC2;
• and
• if the quantized filter LPC3 is received, inverse quantizing the filter LPC3 using, as indicated by the third index, one of absolute inverse quantization, differential inverse quantization relative to the quantized filter LPC2, differential inverse quantization relative to the quantized filter LPC4, and differential inverse quantization relative to both the quantized filters LPC2 and LPC4;
• wherein the method further comprises receiving a quantized filter LPC0 corresponding to a last LPC filter calculated during a previous super-frame, wherein inverse quantizing the filter LPC1 comprises using one of absolute inverse quantization, differential inverse quantization relative to the quantized filter LPC2, and differential inverse quantization relative to both quantized filters LPC2 and LPC0.

A device for inverse quantizing at least one LPC filter in a super-frame including a sequence of frames each associated to a LPC filter, wherein one of the LPC filters is first quantized using absolute quantization and the other LPC filters are subsequently quantized using a quantization process providing, for each of the other LPC filters, a choice of an absolute quantization and of a differential quantization relative to at least one previously quantized filter amongst the LPC filters, and wherein the device for inverse quantizing the at least one LPC filter comprises:

• means for receiving at least the first quantized LPC filter;
• an inverse quantizer of the first quantized LPC filter using absolute inverse quantization;
• and
• if any quantized LPC filter other than the first quantized LPC filter is received, an inverse quantizer of said quantized LPC filter according to the choice of absolute inverse quantization and of differential inverse quantization relative to at least one previously received quantized LPC filter.

A device for inverse quantizing at least one LPC filter in a super-frame including a sequence of a first frame associated to a filter LPC1, a second frame associated to a filter LPC2, a third frame associated to a filter LPC3, and a fourth frame associated to a filter LPC4, wherein the filter LPC4 is first quantized using absolute quantization, the filter LPC2 is quantized using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC4, the filter LPC1 is quantized using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC2, and the filter LPC3 is quantized using a quantization mode selected from the group consisting of absolute quantization, differential quantization relative to the quantized filter LPC2, differential quantization relative to the quantized filter LPC4, and differential quantization relative to both the quantized filters LPC2 and LPC4, wherein the super-frame is coded using a set of coding modes including at least one first coding mode covering a duration of one frame, a second coding mode covering a duration of two frames, and a third coding mode covering a duration of four frames, and wherein the device for inverse quantizing the at least one LPC filter comprises:

• means receiving the first quantized filter LPC4;
• if the first, second, third and fourth frames of the super-frame are not coded using the third coding mode, means for receiving the quantized filter LPC2 and a first index indicative of one of the absolute quantization mode and the differential quantization mode;
• if the first and second frames of the super-frame are coded using the at least one first coding mode, means for receiving the quantized filter LPC1 and a second index indicative of one of the absolute quantization mode and the differential quantization mode;
• if the third and fourth frames of the super-frame are coded using the at least one first coding mode, means for receiving the quantized filter LPC3 and a third index indicative of one of the absolute quantization mode and the differential quantization mode;
• an inverse quantizer of the first quantized LPC filter using absolute inverse quantization;
• if the quantized filter LPC2 is received, an inverse quantizer of the filter LPC2 using, as indicated by the first index, one of absolute inverse quantization and differential inverse quantization relative to the quantized filter LPC4;
• if the quantized filter LPC1 is received, an inverse quantizer of the filter LPC1 using, as indicated by the second index, one of absolute inverse quantization and differential inverse quantization relative to the quantized filter LPC2;
• and
• if the quantized filter LPC3 is received, an inverse quantizer of the filter LPC3 using, as indicated by the third index, one of absolute inverse quantization, differential inverse quantization relative to the quantized filter LPC2, differential inverse quantization relative to the quantized filter LPC4, and differential inverse quantization relative to both the quantized filters LPC2 and LPC4.

A device for inverse quantizing at least one LPC filter in a super-frame including a sequence of a first frame associated to a filter LPC1, a second frame associated to a filter LPC2, a third frame associated to a filter LPC3, and a fourth frame associated to a filter LPC4, wherein the filter LPC4 is first quantized using absolute quantization, the filter LPC2 is quantized using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC4, the filter LPC1 is quantized using a quantization mode selected from the group consisting of absolute quantization and differential quantization relative to the quantized filter LPC2, and the filter LPC3 is quantized using a quantization mode selected from the group consisting of absolute quantization, differential quantization relative to the quantized filter LPC2, differential quantization relative to the quantized filter LPC4, and differential quantization relative to both the quantized filters LPC2 and LPC4, wherein the super-frame is coded using a set of coding modes including at least one first coding mode covering a duration of one frame, a second coding mode covering a duration of two frames, and a third coding mode covering a duration of four frames, and wherein the device for inverse quantizing the at least one LPC filter comprises:

• means receiving the first quantized filter LPC4;
• if the first, second, third and fourth frames of the super-frame are not coded using the third coding mode, means for receiving the quantized filter LPC2 and a first index indicative of one of the absolute quantization mode and the differential quantization mode;
• if the first and second frames of the super-frame are coded using the at least one first coding mode, means for receiving the quantized filter LPC1 and a second index indicative of one of the absolute quantization mode and the differential quantization mode;
• if the third and fourth frames of the super-frame are coded using the at least one first coding mode, means for receiving the quantized filter LPC3 and a third index indicative of one of the absolute quantization mode and the differential quantization mode;
• an inverse quantizer of the first quantized LPC filter using absolute inverse quantization;
• if the quantized filter LPC2 is received, an inverse quantizer of the filter LPC2 using, as indicated by the first index, one of absolute inverse quantization and differential inverse quantization relative to the quantized filter LPC4;
• if the quantized filter LPC1 is received, an inverse quantizer of the filter LPC1 using, as indicated by the second index, one of absolute inverse quantization and differential inverse quantization relative to the quantized filter LPC2;
• and
• if the quantized filter LPC3 is received, an inverse quantizer of the filter LPC3 using, as indicated by the third index, one of absolute inverse quantization, differential inverse quantization relative to the quantized filter LPC2, differential inverse quantization relative to the quantized filter LPC4, and differential inverse quantization relative to both the quantized filters LPC2 and LPC4;
• wherein the device further comprises means for receiving a quantized filter LPC0 corresponding to a last LPC filter calculated during a previous super-frame, wherein the inverse quantizer of the filter LPC1 uses one of absolute inverse quantization, differential inverse quantization relative to the quantized filter LPC2, and differential inverse quantization relative to both quantized filters LPC2 and LPC0.