| US 11,676,616 B2 | ||
| Backward-compatible integration of harmonic transposer for high frequency reconstruction of audio signals | ||
| Lars Villemoes, Järfälla (SE); Heiko Purnhagen, Sundbyberg (SE); and Per Ekstrand, Saltsjobaden (SE) | ||
| Assigned to DOLBY INTERNATIONAL AB, Dublin (IE) | ||
| Filed by DOLBY INTERNATIONAL AB, Dublin (IE) | ||
| Filed on Oct. 11, 2022, as Appl. No. 17/963,743. | ||
| Application 17/078,113 is a division of application No. 16/484,077, filed on Aug. 6, 2019, granted, now 10,818,306, issued on Oct. 27, 2020, previously published as PCT/US2018/023183, filed on Mar. 19, 2018. | ||
| Application 17/963,743 is a continuation of application No. 17/078,113, filed on Oct. 23, 2020. | ||
| Claims priority of provisional application 62/475,619, filed on Mar. 23, 2017. | ||
| Prior Publication US 2023/0036258 A1, Feb. 2, 2023 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. G10L 19/00 (2013.01) | ||
| CPC G10L 19/26 (2013.01) [G10L 19/008 (2013.01); G10L 19/24 (2013.01)] | 6 Claims |
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1. A method for decoding an encoded audio bitstream, the method comprising:
receiving the encoded audio bitstream, the encoded audio bitstream including audio data representing a lowband portion of an audio signal; decoding the audio data to generate a decoded lowband audio signal, wherein the encoded audio bitstream further includes a fill element with an identifier indicating a start of the fill element and fill data after the identifier, wherein the identifier is a three bit unsigned integer transmitted most significant bit first and having a value of 0×6; extracting from the encoded audio bitstream high frequency reconstruction metadata, the high frequency reconstruction metadata including operating parameters for a high frequency reconstruction process that linearly translates a consecutive number of subbands from a lowband portion of the audio signal to a highband portion of the audio signal; filtering the decoded lowband audio signal with an analysis filterbank to generate a filtered lowband audio signal; extracting from the encoded audio bitstream a flag indicating whether either linear translation or harmonic transposition is to be performed on the audio data, wherein the fill data includes the flag; and regenerating a highband portion of the audio signal using the filtered lowband audio signal and the high frequency reconstruction metadata in accordance with the flag,
where p0(n) is a real-valued symmetric or asymmetric prototype filter, M is a number of channels in the analysis filterbank and N is the prototype filter order.wherein the analysis filterbank includes analysis filters, hk(n), that are modulated versions of a prototype filter, p0(n), according to:
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