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EP-4736437-A1 - IMPLICIT MULTIPLE TRANSFORM SELECTION USING INTRA PREDICTION MODE

EP4736437A1EP 4736437 A1EP4736437 A1EP 4736437A1EP-4736437-A1

Abstract

Systems, methods, and instrumentalities are disclosed herein for video encoding/decoding associated with a transform unit (TU). For example, a device (e.g., a video encoding device, such as a video encoder and/or a video decoding device, such as a video decoder) may obtain a TU associated with a video content. Based on the obtained TU, the device may determine a size of the TU. The device may determine that the TU is associated with an intra prediction mode. Based on the size of the TU and based on the determination that the TU is associated with the intra prediction mode, the device may determine the best transform type associated with the TU. Based on the best transform type, the device may perform an inverse transform.

Inventors

  • BONNINEAU, Charles
  • NASER, Karam
  • PURI, Saurabh
  • BOSSEN, FRANK
  • MARZUKI, Ismail

Assignees

  • InterDigital CE Patent Holdings, SAS

Dates

Publication Date
20260506
Application Date
20240607

Claims (14)

  1. 1 . A device for video encoding comprising: a processor configured to: obtain a transform unit (TU) associated with a video content; based on the obtained TU, determine a size of the TU; determine that the TU is associated with an intra prediction mode; based on the size of the TU and based on the determination that the TU is associated with the intra prediction mode, determine the best transform type associated with the TU; and based on the best transform type, perform an inverse transform.
  2. 2. A device for video decoding comprising: a processor configured to: obtain a transform unit (TU) associated with a video content; based on the obtained TU, determine a size of the TU; determine that the TU is associated with an intra prediction mode; based on the size of the TU and based on the determination that the TU is associated with the intra prediction mode, determine the best transform type associated with the TU; and based on the best transform type, perform an inverse transform.
  3. 3. The device of claim 1 or claim 2, wherein the processor is configured to: determine that the TU is associated with at least one of a planar mode or a matrix-based intra prediction (MIP) mode; and based on the determination that the TU is associated with at least one of the planar mode or the MIP mode, determine the best transform type associated with the TU based on an explicit multiple transform selection (MTS).
  4. 4. The device of claim 1 or claim 2, wherein the processor is configured to: obtain a lookup table associated with an MTS; and based on the size of the TU, the intra prediction mode, and the lookup table, determine the best transform type associated with the TU.
  5. 5. The device of claim 1 or claim 2, wherein the processor is configured to: obtain an implicit MTS indication, wherein the implicit MTS indication is configured to indicate whether an implicit MTS has been enabled; based on the obtained implicit MTS indication, determine whether the implicit MTS has been enabled; and based on a determination that the implicit MTS has been enabled, determine that the TU is associated with the intra prediction mode.
  6. 6. A method for video decoding comprising: obtaining a transform unit (TU) associated with a video content; based on the obtained TU, determining a size of the TU; determining that the TU is associated with an intra prediction mode; based on the size of the TU and based on the determination that the TU is associated with the intra prediction mode, determining the best transform type associated with the TU; and based on the best transform type, performing an inverse transform.
  7. 7. A method for video encoding comprising: obtaining a transform unit (TU) associated with a video content; based on the obtained TU, determining a size of the TU; determining that the TU is associated with an intra prediction mode; based on the size of the TU and based on the determination that the TU is associated with the intra prediction mode, determining the best transform type associated with the TU; and based on the best transform type, performing an inverse transform.
  8. 8. The method of claim 6 or claim 7, wherein the method comprises: determining that the TU is associated with at least one of a planar mode or a matrix-based intra prediction (MIP) mode; and based on the determination that the TU is associated with at least one of the planar mode or the MIP mode, determining the best transform type associated with the TU based on an explicit multiple transform selection (MTS).
  9. 9. The method of claim 6 or claim 7, wherein the method comprises: obtaining a lookup table associated with an MTS; and based on the size of the TU, the intra prediction mode, and the lookup table, determining the best transform type associated with the TU.
  10. 10. The method of claim 6 or claim 7, wherein the method comprises: obtaining an implicit MTS indication, wherein the implicit MTS indication is configured to indicate whether an implicit MTS has been enabled; based on the obtained implicit MTS indication, determining whether the implicit MTS has been enabled; and based on a determination that the implicit MTS has been enabled, determining that the TU is associated with the intra prediction mode.
  11. 11. A computer readable storage medium including instructions for video decoding, causing a processor to perform the method of any one of claims 6 or 8-10.
  12. 12. A computer readable storage medium including instructions for video encoding, causing a processor to perform the method of any one of claims 7-10.
  13. 13. A non-transitory computer readable storage medium including instructions for video decoding, causing a processor to perform the method of any one of claims 6 or 8-10.
  14. 14. A non-transitory computer readable storage medium including instructions for video encoding, causing a processor to perform the method of any one of claims 7-10.

Description

IMPLICIT MULTIPLE TRANSFORM SELECTION USING INTRA PREDICTION MODE CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of European Provisional Application No. 23306074.8 filed June 29, 2023, the contents of which are incorporated by reference herein. BACKGROUND [0002] Video coding systems may be used to compress digital video signals, e.g., to reduce the storage and/or transmission bandwidth needed for such signals. Video coding systems may include, for example, block-based, wavelet-based, and/or object-based systems. SUMMARY [0003] Systems, methods, and instrumentalities are disclosed herein for video encoding and/or video decoding. In examples, a device for video encoding, such as a video encoder, and/or a device for video decoding, such as a video decoder, may be configured to perform one or more of the following. [0004] The device may obtain a transform unit (TU) associated with video content. Based on the obtained TU, the device may determine a size of the TU. The device may determine that the TU is associated with an intra prediction mode. Based on the size of the TU and based on the determination that the TU is associated with the intra prediction mode, the device may determine the best transform type associated with the TU. Based on the best transform type, the device may perform an inverse transform. [0005] In examples, the device may determine that the TU is associated with at least one of a planar mode or a matrix-based intra prediction (MIP) mode. Based on the determination that the TU is associated with at least one of the planar mode or the MIP mode, the device may determine the best transform type associated with the TU based on an explicit multiple transform selection (MTS). [0006] In examples, the device may obtain a lookup table associated with an MTS. Based on the size of the TU, the intra prediction mode, and/or the lookup table, the device may determine the best transform type associated with the TU. [0007] In examples, the device may obtain an implicit MTS indication. The implicit MTS indication may be configured to indicate whether an implicit MTS has been enabled. Based on the obtained implicit MTS indication, the device may determine whether the implicit MTS has been enabled. Based on a determination that the implicit MTS has been enabled, the device may determine that the TU is associated with the intra prediction mode. [0008] In examples, a device for video encoding and/or a device for video decoding may be configured to use multiple transform selection (MTS). For example, a device for video encoding may obtain two or more intra prediction modes. In examples, the two or more intra prediction modes may be the same. In examples, the two or more intra prediction modes may be different. Based on the obtained intra prediction modes, the device may determine that at least two or more intra prediction modes are consecutive prediction modes. Based on the determination that at least two or more intra prediction modes are consecutive prediction modes, the device may alternate between transform types. For example, the device may alternate the transform types during a rate-distortion optimization procedure. The transform types described herein may be at least one of discrete cosine transforms (DCT5), DCT8, DCT2, discrete sine transforml (DST1), DST4, DST7, identity transform (IDT), and/or the like. [0009] The device may determine whether an implicit MTS has been enabled. Based on a determination that the implicit MTS has been enabled, the device may compute an index of a transform pair in a set (trldx). Based on a determination that the implicit MTS has been enabled, the device may skip signaling the trldx to a device (e.g., a second device) for video decoding, such as a decoder. The device may send an implicit MTS enabled indication in video data, such as bitstream. The implicit MTS enabled indication may be configured to indicate whether the implicit MTS has been enabled. [0010] These examples may be performed by a device with a processor. The device may be an encoder or a decoder. These examples may be performed by a computer program product which is stored on a non-transitory computer readable medium and includes program code instructions. These examples may be performed by a computer program comprising program code instructions. [0011] Systems, methods, and instrumentalities described herein may involve a decoder. In some examples, the systems, methods, and instrumentalities described herein may involve an encoder. In some examples, the systems, methods, and instrumentalities described herein may involve a signal (e.g., from an encoder and/or received by a decoder). A computer-readable medium may include instructions for causing one or more processors to perform methods described herein. A computer program product may include instructions which, when the program is executed by one or more processors, may cause the one or more processors to carry out the me