CODER USING FORWARD ALIASING CANCELLATION
First Claim
1. Decoder for decoding a data stream comprising a sequence of frames into which time segments of an information signal are coded, respectively, comprisinga parser configured to parse the data stream , wherein the parser is configured to, in parsing the data stream, read a first syntax portion and a second syntax portion from a current frame;
- anda reconstructor configured to reconstruct a current time segment of the information signal associated with the current frame based on information acquired from the current frame by the parsing, using a first selected one of a Time-Domain Aliasing Cancellation transform decoding mode and a time-domain decoding mode, the first selection depending on the first syntax portion,wherein the parser is configured to, in parsing the data stream, perform a second selected one of a first action of expecting the current frame to comprise, and thus reading forward aliasing cancellation data from the current frame and a second action of not-expecting the current frame to comprise, and thus not reading forward aliasing cancellation data from the current frame, the second selection depending on the second syntax portion,wherein the reconstructor is configured to perform forward aliasing cancellation at a boundary between the current time segment and a previous time segment of a previous frame using the forward aliasing cancellation data.
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Abstract
A codec supporting switching between time-domain aliasing cancellation transform coding mode and time-domain coding mode is made less liable to frame loss by adding a further syntax portion to the frames, depending on which the parser of the decoder may select between a first action of expecting the current frame to have, and thus reading forward aliasing cancellation data from the current frame and a second action of not-expecting the current frame to have, and thus not reading forward aliasing cancellation data from the current frame. In other words, while a bit of coding efficiency is lost due to the provision of the new syntax portion, it is merely the new syntax portion which provides for the ability to use the codec in case of a communication channel with frame loss. Without the new syntax portion, the decoder would not be capable of decoding any data stream portion after a loss and will crash in trying to resume parsing. Thus, in an error prone environment, the coding efficiency is prevented from vanishing by the introduction of the new syntax portion.
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Citations
21 Claims
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1. Decoder for decoding a data stream comprising a sequence of frames into which time segments of an information signal are coded, respectively, comprising
a parser configured to parse the data stream , wherein the parser is configured to, in parsing the data stream, read a first syntax portion and a second syntax portion from a current frame; - and
a reconstructor configured to reconstruct a current time segment of the information signal associated with the current frame based on information acquired from the current frame by the parsing, using a first selected one of a Time-Domain Aliasing Cancellation transform decoding mode and a time-domain decoding mode, the first selection depending on the first syntax portion, wherein the parser is configured to, in parsing the data stream, perform a second selected one of a first action of expecting the current frame to comprise, and thus reading forward aliasing cancellation data from the current frame and a second action of not-expecting the current frame to comprise, and thus not reading forward aliasing cancellation data from the current frame, the second selection depending on the second syntax portion, wherein the reconstructor is configured to perform forward aliasing cancellation at a boundary between the current time segment and a previous time segment of a previous frame using the forward aliasing cancellation data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. Encoder for encoding an information signal into data stream such that the data stream comprises a sequence of frames into which time segments of the information signal are coded, respectively, comprising
a constructor configured to code a current time segment of the information signal into information of the current frame using a first selected one of a Time-Domain Aliasing Cancellation transform coding mode and a time-domain coding mode; - and
an inserter configured to insert the information into the current frame along with a first syntax portion and a second syntax portion, wherein the first syntax portion signals the first selection, wherein the constructor and inserter are configured to determine forward aliasing cancellation data for forward aliasing cancellation at a boundary between the current time segment and a previous time segment of a previous frame and insert the forward aliasing cancellation data into the current frame in case the current frame and the previous frame are encoded using different ones of the Time-Domain Aliasing Cancellation transform coding mode and the time-domain coding mode, and refraining from inserting any forward aliasing cancellation data into the current frame in case the current frame and the previous frame are encoded using equal ones of the Time-Domain Aliasing Cancellation transform coding mode and the time-domain coding mode, wherein the second syntax portion is set depending on as to whether the current frame and the previous frame are encoded using equal or different ones of the Time-Domain Aliasing Cancellation transform coding mode and the time-domain coding mode. - View Dependent Claims (16)
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17. Method for decoding a data stream comprising a sequence of frames into which time segments of an information signal are coded, respectively, comprising
parsing the data stream, wherein parsing the data stream comprises reading a first syntax portion and a second syntax portion from a current frame; - and
reconstructing a current time segment of the information signal associated with the current frame based on information acquired from the current frame by the parsing, using a first selected one of a Time-Domain Aliasing Cancellation transform decoding mode and a time-domain decoding mode, the first selection depending on the first syntax portion, wherein, in parsing the data stream, a second selected one of a first action of expecting the current frame to comprise, and thus reading forward aliasing cancellation data from the current frame and a second action of not-expecting the current frame to comprise, and thus not reading forward aliasing cancellation data from the current frame is performed, the second selection depending on the second syntax portion, wherein the reconstructing comprises performing forward aliasing cancellation at a boundary between the current time segment and a previous time segment of a previous frame using the forward aliasing cancellation data.
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18. Method for encoding an information signal into data stream such that the data stream comprises a sequence of frames into which time segments of the information signal are coded, respectively, comprising
coding a current time segment of the information signal into information of the current frame using a first selected one of a Time-Domain Aliasing Cancellation transform encoding mode and a time-domain encoding mode; - and
inserting the information into the current frame along with a first syntax portion and a second syntax portion, wherein the first syntax portion signals the first selection, determining forward aliasing cancellation data for forward aliasing cancellation at a boundary between the current time segment and a previous time segment of a previous frame and inserting the forward aliasing cancellation data into the current frame in case the current frame and the previous frame are encoded using different ones of the Time-Domain Aliasing Cancellation transform encoding mode and the time-domain encoding mode, and refraining from inserting any forward aliasing cancellation data into the current frame in case the current frame and the previous frame are encoded using equal ones of the Time-Domain Aliasing Cancellation transform encoding mode and the time-domain encoding mode, wherein the second syntax portion is set depending on as to whether the current frame and the previous frame are encoded using equal or different ones of the Time-Domain Aliasing Cancellation transform encoding mode and the time-domain encoding mode.
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19. Data stream comprising a sequence of frames into which time segments of an information signal are coded, respectively, each frame comprising a first syntax portion, a second syntax portion, and information into which a time segment associated with the respective frame is coded using a first selected one of a Time-Domain Aliasing Cancellation transform coding mode and a time-domain coding mode, the first selection depending on the first syntax portion of the respective frame, wherein each frame comprises forward aliasing cancellation data or not depending on the second syntax portion of the respective frame, wherein the second syntax portion indicates that the respective frame comprises forward aliasing cancellation data of the respective frame and the previous frame are coded using different ones of the Time-Domain Aliasing Cancellation transform coding mode and the time-domain coding mode so that forward aliasing cancellation using the forward aliasing cancellation data is possible at the boundary between the respective time segment and a previous time segment associated with the previous frame.
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20. A computer program comprising a program code for performing, when running on a computer, a method for decoding a data stream comprising a sequence of frames into which time segments of an information signal are coded, respectively, comprising
parsing the data stream, wherein parsing the data stream comprises reading a first syntax portion and a second syntax portion from a current frame; - and
reconstructing a current time segment of the information signal associated with the current frame based on information acquired from the current frame by the parsing, using a first selected one of a Time-Domain Aliasing Cancellation transform decoding mode and a time-domain decoding mode, the first selection depending on the first syntax portion, wherein, in parsing the data stream, a second selected one of a first action of expecting the current frame to comprise, and thus reading forward aliasing cancellation data from the current frame and a second action of not-expecting the current frame to comprise, and thus not reading forward aliasing cancellation data from the current frame is performed, the second selection depending on the second syntax portion, wherein the reconstructing comprises performing forward aliasing cancellation at a boundary between the current time segment and a previous time segment of a previous frame using the forward aliasing cancellation data.
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21. A computer program comprising a program code for performing, when running on a computer, a method for encoding an information signal into data stream such that the data stream comprises a sequence of frames into which time segments of the information signal are coded, respectively, comprising
coding a current time segment of the information signal into information of the current frame using a first selected one of a Time-Domain Aliasing Cancellation transform encoding mode and a time-domain encoding mode; - and
inserting the information into the current frame along with a first syntax portion and a second syntax portion, wherein the first syntax portion signals the first selection, determining forward aliasing cancellation data for forward aliasing cancellation at a boundary between the current time segment and a previous time segment of a previous frame and inserting the forward aliasing cancellation data into the current frame in case the current frame and the previous frame are encoded using different ones of the Time-Domain Aliasing Cancellation transform encoding mode and the time-domain encoding mode, and refraining from inserting any forward aliasing cancellation data into the current frame in case the current frame and the previous frame are encoded using equal ones of the Time-Domain Aliasing Cancellation transform encoding mode and the time-domain encoding mode, wherein the second syntax portion is set depending on as to whether the current frame and the previous frame are encoded using equal or different ones of the Time-Domain Aliasing Cancellation transform encoding mode and the time-domain encoding mode.
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Specification