Fragment-aligned audio coding

A decoder for decoding audio content from an encoded data stream, comprising

• an input interface configured to receive encoded representations of temporal fragments of the audio content, each of which has encoded thereinto a respective temporal fragment in units of audio frames temporally aligned to a beginning of the respective temporal fragment so that the beginning of the respective temporal fragment coincides with a beginning of a first audio frame of the audio frames;
• a decoding stage configured to decode reconstructed versions of the temporal fragments of the audio content from the encoded representations of the temporal fragments;
• and
• a joiner configured to join, for playout, the reconstructed versions of the temporal fragments of the audio content together,
• wherein a temporal length between fragment boundaries of the fragment grid is a non-integer multiple of a temporal length of the audio frames,
• wherein the joiner is configured to truncate the reconstructed version of a predetermined temporal fragment at a portion of a trailing audio frame of the audio frames in units of which the predetermined temporal fragment is coded into the encoded representation of the predetermined temporal fragment, which temporally exceeds a trailing end of the predetermined temporal fragment and temporally overlaps with a reconstructed version of an immediately succeeding temporal fragment,
• wherein the decoder is configured to determine the portion of the trailing audio frame on the basis of truncation information in the encoded data stream, wherein the truncation information comprises
• a frame length value indicating a temporal length of the audio frames in units of which the predetermined temporal fragment is coded into the encoded representation of the predetermined temporal fragment, and a fragment length value indicating a temporal length of the predetermined temporal fragment from the beginning of the reconstructed version of the predetermined fragment to the fragment boundary with which the beginning of the reconstructed version of the succeeding temporal fragment coincides, and/or
• a truncation length value indicating a temporal length of the portion of the trailing audio frame or the difference between the temporal length of the portion of the trailing audio frame and the temporal length of the trailing audio frame.

A method for encoding audio content into an encoded data stream, using an encoding stage configured to encode the audio content in units of frames, the method comprising

• providing the audio content to the encoding stage in units of temporal fragments by providing, for a currently provided temporal fragment, a portion of the audio content to the encoding stage which comprises the currently provided temporal fragment,
• encoding, performed by the encoding stage, each temporal fragment into an encoded representation of the respective temporal fragment in units of audio frames, wherein the audio content is provided to the encoding stage such that the audio frames are aligned to the respective temporal fragment such that for each temporal fragment a beginning of first audio frame of the audio frames in units of which the respective temporal fragment is encoded into the encoded representation of the respective temporal fragment and a beginning of the respective temporal fragment coincide,
• wherein the encoded representations of the temporal fragments are comprised by the encoded data stream, and a temporal length of the temporal fragments is a non-integer multiple of a temporal length of the frames,
• wherein the method comprises signaling within the encoded data stream a truncation information for identifying a portion of a trailing audio frame of the audio frames in units of which the temporal fragments are encoded, which exceeds a trailing end of the temporal fragments and temporally overlaps with a immediately succeeding temporal fragment of the fragment grid, wherein the truncation information comprises
• a frame length value indicating the temporal length of the audio frames and a fragment length value indicating the temporal length of the temporal fragments and/or
• a truncation length value indicating a temporal length of a portion of a trailing audio frame of the audio frames in units of which the temporal fragments are encoded, which exceeds a trailing end of the temporal fragments and temporally overlaps with a immediately succeeding temporal fragment of the fragment grid, or the difference between the temporal length of the portion of the trailing audio frame and the temporal length of the trailing audio frame.

A method for decoding audio content in units of temporal fragments of a fragment grid from an encoded data stream, comprising

• receiving encoded representations of temporal fragments of the audio content, each of which has encoded thereinto a respective temporal fragment in units of audio frames temporally aligned to a beginning of the respective temporal fragment so that the beginning of the respective temporal fragment coincides with a beginning of a first audio frame of the audio frames;
• decode reconstructed versions of the temporal fragments of the audio content from the encoded representations of the temporal fragments;
• and
• joining, for playout, the reconstructed versions of the temporal fragments of the audio content together,
• wherein a temporal length between fragment boundaries of the fragment grid is a non-integer multiple of a temporal length of the audio frames,
• wherein the joining comprises truncating the reconstructed version of a predetermined temporal fragment at a portion of a trailing audio frame of the audio frames in units of which the predetermined temporal fragment is coded into the encoded representation of the predetermined temporal fragment, which temporally exceeds a trailing end of the predetermined temporal fragment and temporally overlaps with a reconstructed version of an immediately succeeding temporal fragment,
• wherein the method further comprises determining the portion of the trailing audio frame on the basis of truncation information in the encoded data stream,
• wherein the truncation information comprises
• a frame length value indicating a temporal length of the audio frames in units of which the predetermined temporal fragment is coded into the encoded representation of the predetermined temporal fragment, and a fragment length value indicating a temporal length of the predetermined temporal fragment from the beginning of the reconstructed version of the predetermined fragment to the fragment boundary with which the beginning of the reconstructed version of the succeeding temporal fragment coincides, and/or
• a truncation length value indicating a temporal length of the portion of the trailing audio frame or the difference between the temporal length of the portion of the trailing audio frame and the temporal length of the trailing audio frame.

A non-transitory digital storage medium having a computer program stored thereon to perform the method for encoding audio content into an encoded data stream, using an encoding stage configured to encode the audio content in units of frames, the method comprising

• providing the audio content to the encoding stage in units of temporal fragments by providing, for a currently provided temporal fragment, a portion of the audio content to the encoding stage which comprises the currently provided temporal fragment,
• encoding, performed by the encoding stage, each temporal fragment into an encoded representation of the respective temporal fragment in units of audio frames, wherein the audio content is provided to the encoding stage such that the audio frames are aligned to the respective temporal fragment such that for each temporal fragment a beginning of first audio frame of the audio frames in units of which the respective temporal fragment is encoded into the encoded representation of the respective temporal fragment and a beginning of the respective temporal fragment coincide,
• wherein the encoded representations of the temporal fragments are comprised by the encoded data stream, and a temporal length of the temporal fragments is a non-integer multiple of a temporal length of the frames,
• wherein the method comprises signaling within the encoded data stream a truncation information for identifying a portion of a trailing audio frame of the audio frames in units of which the temporal fragments are encoded, which exceeds a trailing end of the temporal fragments and temporally overlaps with a immediately succeeding temporal fragment of the fragment grid, wherein the truncation information comprises
• a frame length value indicating the temporal length of the audio frames and a fragment length value indicating the temporal length of the temporal fragments and/or
• a truncation length value indicating a temporal length of a portion of a trailing audio frame of the audio frames in units of which the temporal fragments are encoded, which exceeds a trailing end of the temporal fragments and temporally overlaps with a immediately succeeding temporal fragment of the fragment grid, or the difference between the temporal length of the portion of the trailing audio frame and the temporal length of the trailing audio frame,
• when said computer program is run by a computer.

A non-transitory digital storage medium having a computer program stored thereon to perform the method for decoding audio content in units of temporal fragments of a fragment grid from an encoded data stream, comprising

• receiving encoded representations of temporal fragments of the audio content, each of which has encoded thereinto a respective temporal fragment in units of audio frames temporally aligned to a beginning of the respective temporal fragment so that the beginning of the respective temporal fragment coincides with a beginning of a first audio frame of the audio frames;
• decode reconstructed versions of the temporal fragments of the audio content from the encoded representations of the temporal fragments;
• and
• joining, for playout, the reconstructed versions of the temporal fragments of the audio content together,
• wherein a temporal length between fragment boundaries of the fragment grid is a non-integer multiple of a temporal length of the audio frames,
• wherein the joining comprises truncating the reconstructed version of a predetermined temporal fragment at a portion of a trailing audio frame of the audio frames in units of which the predetermined temporal fragment is coded into the encoded representation of the predetermined temporal fragment, which temporally exceeds a trailing end of the predetermined temporal fragment and temporally overlaps with a reconstructed version of an immediately succeeding temporal fragment,
• wherein the method further comprises determining the portion of the trailing audio frame on the basis of truncation information in the encoded data stream,
• wherein the truncation information comprises
• a frame length value indicating a temporal length of the audio frames in units of which the predetermined temporal fragment is coded into the encoded representation of the predetermined temporal fragment, and a fragment length value indicating a temporal length of the predetermined temporal fragment from the beginning of the reconstructed version of the predetermined fragment to the fragment boundary with which the beginning of the reconstructed version of the succeeding temporal fragment coincides, and/or a truncation length value indicating a temporal length of the portion of the trailing audio frame or the difference between the temporal length of the portion of the trailing audio frame and the temporal length of the trailing audio frame,
• when said computer program is run by a computer.