US 12,243,543 B2
Integration of high frequency reconstruction techniques with reduced post-processing delay
Kristofer Kjoerling, Solna (SE); Lars Villemoes, Järfälla (SE); Heiko Purnhagen, Sundbyberg (SE); and Per Ekstrand, Saltsjöbaden (SE)
Assigned to DOLBY INTERNATIONAL AB, Dublin (IE)
Filed by DOLBY INTERNATIONAL AB, Dublin (IE)
Filed on Jan. 19, 2024, as Appl. No. 18/417,902.
Application 18/417,902 is a continuation of application No. 18/157,644, filed on Jan. 20, 2023, granted, now 11,908,486.
Application 18/157,644 is a continuation of application No. 17/050,664, granted, now 11,562,759, issued on Jan. 24, 2023, previously published as PCT/US2019/029144, filed on Apr. 25, 2019.
Claims priority of provisional application 62/662,296, filed on Apr. 25, 2018.
Prior Publication US 2024/0161763 A1, May 16, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G10L 19/18 (2013.01); G10L 21/038 (2013.01)
CPC G10L 19/18 (2013.01) [G10L 21/038 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A method for performing high frequency reconstruction of an audio signal, the method comprising:
receiving an encoded audio bitstream, the encoded audio bitstream including audio data representing a lowband portion of the audio signal and high frequency reconstruction metadata, wherein the high frequency reconstruction metadata includes noise scale factors;
decoding the audio data to generate a decoded lowband audio signal;
extracting from the encoded audio bitstream the high frequency reconstruction metadata, the high frequency reconstruction metadata including operating parameters for a high frequency reconstruction process, the operating parameters including a patching mode parameter located in a backward-compatible extension container of the encoded audio bitstream, wherein a first value of the patching mode parameter indicates spectral translation and a second value of the patching mode parameter indicates harmonic transposition by phase-vocoder frequency spreading;
filtering the decoded lowband audio signal to generate a filtered lowband audio signal; and
regenerating a highband portion of the audio signal using the filtered lowband audio signal and the high frequency reconstruction metadata, wherein the regenerating includes spectral translation if the patching mode parameter is the first value and the regenerating includes harmonic transposition by phase-vocoder frequency spreading if the patching mode parameter is the second value,
wherein the filtering and regenerating are performed as a post-processing operation with a delay of 3010 samples per audio channel and wherein the spectral translation comprises maintaining a ratio between tonal and noise-like components by adaptive inverse filtering.