Patent ID: 11962813
Assignee: FRAUNHOFER GESELLSCHAFT ZUR FÖRDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method for video decoding by use of a coded picture buffer (CPB) and a decoded picture buffer (DPB), the method comprising
receiving a data stream having pictures of a video encoded thereinto along a coding order as a sequence of access units (AU),
feeding the sequence of access units sequentially into the CPB using a selected bitrate with halting the feeding with respect to access units for which a virtual time of availability according to a temporal frame removal raster preponed by, for a first access unit in the coding order, a selected temporal removal delay and, for subsequent access units in coding order, a sum of the selected temporal removal delay and a selected temporal offset has not yet been reached, until the virtual time of availability is reached;
removing the AUs from the CPB AU-wise using the temporal raster,
extracting from the data stream first CPB parameters relating to a first operation point and second CPB parameters relating to a second operation point, each of the first and the second CPB parameters being indicative of a CPB size, a predetermined temporal offset, a predetermined temporal removal delay and a predetermined bitrate, wherein the first CPB parameters differ from the second CPB parameters at least with respect to the predetermined bitrate,
determining the selected temporal offset by interpolating, at the selected bitrate, between the predetermined temporal offset indicated by the first CPB parameters and the predetermined temporal offset indicated by the second CPB parameters and the selected temporal removal delay by interpolating, at the selected bitrate, between the predetermined temporal removal delay indicated by the first CPB parameters and the predetermined temporal removal delay indicated by the second CPB parameters,
decoding a current AU removed from the CPB using inter-picture prediction from a referenced reference picture stored in the DPB to acquire a decoded picture, and
inserting the decoded picture into the DPB,
assigning to each reference picture stored in the DPB a classification as one of a short-term reference picture, a long-term reference picture and an unused-for-reference picture,
reading DPB mode information from the current AU,
if the DPB mode information indicates a first mode, remove one or more reference pictures classified as a short-term picture, according to a first-in-first-out (FIFO) strategy, from the DPB,
if the DPB mode information indicates a second mode,
reading memory management control information comprising at least one command in the current AU and execute the at least one command so as to change the classification assigned to at least one of the reference pictures stored in the DPB, and use the classification of the reference pictures in the DPB, for managing reference picture removal from the DPB,

wherein the method comprises one or more of:
if the at least one command in the current AU is a first command,
re-classifying a reference picture in the DPB, classified to be a short-term reference picture, as an unused-for-reference picture,

if the at least one command in the current AU is a second command,
re-classifying a reference picture in the DPB, classified to be a long-term reference picture, as an unused-for-reference picture,

if the at least one command in the current AU is a third command,
re-classifying a reference picture in the DPB, classified to be a short-term picture, as a long-term reference picture, and assign a frame index to the re-classified reference picture,

if the at least one command in the current AU is a fourth command,
setting an upper frame index limit according to the fourth command, and re-classify all reference picture in the DPB, classified to be a long-term picture, and having assigned thereto a frame index exceeding the upper frame index limit, as an unused-for-reference picture,

if the at least one command in the current AU is a fifth command, classifying the current picture as a long-term picture, and assigning a frame index to the current picture.