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 obtained 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, wherein the first and second syntax portions are comprised by each frame, wherein the first syntax portion associates the respective frame from which the first syntax portion has been read, with a first frame type or a second frame type and, if the respective frame is of the second frame type, associates sub frames of a sub division of the respective frame, composed of a number of sub frames, with a respective one of a first sub frame type and a second sub frame type, wherein the reconstructor is configured to, if the first syntax portion associates the respective frame with the first frame type, use frequency domain decoding as a first version of the time-domain aliasing cancellation transform decoding mode to reconstruct the time segment associated with the respective frame, and, if the first syntax portion associates the respective frame with the second frame type, use, for each sub frame of the respective frame, transform coded excitation linear prediction decoding as a second version of the time-domain aliasing cancellation transform decoding mode to re-construct a sub portion of the time segment of the respective frame, which is associated with respected sub frame, if the first syntax portion associates the respective sub frame of the respective frame with the first sub frame type, and codebook excitation linear prediction decoding as the time-domain decoding mode to reconstruct a sub portion of the time segment of the respective frame, which is associated with the respective sub frame, if the first syntax portion associates the respective sub frame with a second sub frame type, wherein the second syntax portion comprises a first flag signaling as to whether forward aliasing cancellation data is present or not in the respective frame, and the parser is configured to perform the second selection depending on the first flag, and wherein the second syntax portion further comprises a second flag merely within frames of the second frame type, the second flag signaling as to whether the previous frame is of the first frame type or of the second frame type with the last sub frame thereof being of the first sub frame type, wherein the parser is configured to perform the reading of the forward aliasing cancellation data from the current frame, if the current frame is of the second frame type, depending on the second flag in that a forward aliasing cancellation gain is parsed from the forward aliasing cancellation data in case of the previous frame being of the first frame type, and not if previous frame being of the second frame type with the last sub frame thereof being of the first sub frame type, wherein the reconstructor is configured to perform the forward aliasing cancellation at an intensity which depends on the forward aliasing cancellation gain in case of the previous frame being of the first frame type. 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,