# US 10,771,780 B2 · Method and apparatus for signaling and construction of video coding reference picture lists

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- Number: US 10,771,780 B2
- Document ID: US10771780B2
- Status: Granted
- Kind: B2
- Application number: 15/260,392
- Filed: 2016-09-09
- Published: 2016-12-29
- Granted: 2020-09-08
- Earliest claimed: 2012-01-19
- Assignees: Vid Scale, Inc.
- Applicants: Vid Scale, Inc.
- Inventors: Yan Ye; Yong He
- Web page: https://patentgrep.com/patent/US10771780B2

## CPC

- H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
- H04N 19/103: Selection of coding mode or of prediction mode
- H04N 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635)
- H04N 19/124: Quantisation
- H04N 19/13: Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
- H04N 19/139: Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
- H04N 19/15: by monitoring actual compressed data size at the memory before deciding storage at the transmission buffer
- H04N 19/503: involving temporal prediction (adaptive coding with adaptive selection between spatial and temporal predictive coding H04N19/107; adaptive coding with adaptive selection among a plurality of temporal predictive coding modes H04N19/109)
- H04N 19/577: Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
- H04N 19/61: in combination with predictive coding
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N 19/172: the region being a picture, frame or field
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

Improved method and apparatus for signaling of reference pictures used for temporal prediction. The signaling schemes and construction process for different reference picture lists in HEVC Working Draft 5 (WD5) are improved.

## Claims

### Claim 1

A video decoder apparatus, comprising:
a processor configured to generate a temporary ordered list of reference pictures from a decoded picture buffer (DPB), in which the temporary ordered list is ordered with any reference pictures for a current picture that is currently being decoded that are in the DPB and that are temporally before the current picture listed in order by temporal distance from the current picture, followed by any reference pictures for the current picture that are in the DPB and that are temporally later than the current picture listed in order by temporal distance from the current picture, followed by any long term reference pictures for the current picture that are in the DPB; and
the processor further configured to generate a reference picture list by selecting reference pictures from the temporary ordered list of reference pictures, wherein, when the reference picture list is to be a modified list, generating the reference picture list by, at least, for each entry in the reference picture list, reading an index into the temporary ordered list of reference pictures and selecting, for the entry in the reference picture list, a reference picture from the temporary ordered list of reference pictures that is identified by the index.

### Claim 2 (depends on 1)

The decoder apparatus of claim 1, wherein the processor is further configured to read data indicating if the reference picture list is to be the modified list.

### Claim 3 (depends on 2)

The decoder apparatus of claim 2, wherein the processor is further configured to, if the reference picture list is not to be the modified list, generate the reference picture list by taking entries from the temporary ordered list of reference pictures in order up to a first specified number of entries.

### Claim 4 (depends on 2)

The decoder apparatus of claim 2, wherein the processor is further configured to determine if the reference picture list is to be the modified list by reading a syntax element ref_pic_list_modification_flag_l0.

### Claim 5 (depends on 2)

The decoder apparatus of claim 2, wherein the index is in a range of zero to a number of pictures in the DPB.

### Claim 6 (depends on 2)

The decoder apparatus of claim 2, wherein the index is specified by a syntax element ref_pic_set_idx.

### Claim 7 (depends on 6)

The decoder apparatus of claim 6, wherein:
the processor is further configured to read a syntax element ref_pic_list_modification_flag_l0;
the syntax element ref_pic_list_modification_flag_l0 being equal to a first value specifies that the syntax element ref_pic_set_idx is present for use in generating the reference picture list; and
the syntax element ref_pic_list_modification_flag_l0 being equal to a second value specifies that the syntax element ref_pic_set_idx is not present for use in generating the reference picture list.

### Claim 8 (depends on 7)

The decoder apparatus of claim 7, wherein, if the syntax element ref_pic_set_idx is not present in association with the reference picture list, the index is set to zero.

### Claim 9 (depends on 6)

The decoder apparatus of claim 6, wherein the long term reference pictures are listed in the temporary ordered list of reference pictures in the order in which the long term reference pictures are stored in the DPB.

### Claim 10 (depends on 1)

The decoder apparatus of claim 1, wherein the processor is further configured to:
generate a second temporary ordered list of reference pictures from the DPB; and
generate a second reference picture list wherein, when the second reference picture list is to be a second modified list, generating the second reference picture list by, at least, for each entry in the second reference picture list, reading a second index into the second temporary ordered list of reference pictures and selecting, for the entry in the second reference picture list, a reference picture from the second temporary ordered list of reference pictures that is identified by that second index.

### Claim 11 (depends on 10)

The decoder apparatus of claim 10, wherein the processor is further configured to read data indicating if the second reference picture list is to be the second modified list.

### Claim 12 (depends on 11)

The decoder apparatus of claim 11, wherein the processor is further configured to,
when the second reference picture list is not to be the second modified list, generate the second reference picture list by taking entries from the second temporary ordered list of reference pictures in order up to a second specified number of entries.

### Claim 13 (depends on 11)

The decoder apparatus of claim 11, wherein the processor is further configured to determine if the second reference picture list is to be the second modified list by reading a syntax element ref_pic_list_modification_flag_l1.

### Claim 14 (depends on 11)

The decoder apparatus of claim 11, wherein the second index is in a range of zero to a number of pictures in the DPB.

### Claim 15 (depends on 11)

The decoder apparatus of claim 11, wherein the second index is specified by a syntax element ref_pic_set_idx.

### Claim 16 (depends on 15)

The decoder apparatus of claim 15, wherein:
the processor is further configured to read a syntax element ref_pic_list_modification_flag_l1;
the syntax element ref_pic_list_modification_flag_l1 being equal to a first value specifies that the syntax element ref_pic_set_idx is present for use in generating the second reference picture list; and
the syntax element ref_pic_list_modification_flag_l1 being equal to a second value specifies that the syntax element ref_pic_set_idx is not present for use in generating the second reference picture list.

### Claim 17 (depends on 16)

The decoder apparatus of claim 16, wherein, if the syntax element ref_pic_set_idx is not present in association with the second reference picture list, the second index is set to zero.

### Claim 18

A method of generating a reference picture list, the method comprising:
generating a temporary ordered list of reference pictures from a decoded picture buffer (DPB), in which the temporary ordered list is ordered with any reference pictures for a current picture that is currently being decoded that are in the DPB and that are temporally before the current picture listed in order by temporal distance from the current picture, followed by any reference pictures for the current picture that are in the DPB and that are temporally later than the current picture listed in order by temporal distance from the current picture, followed by any long term reference pictures for the current picture that are in the DPB; and
generating a reference picture list by selecting reference pictures from the temporary ordered list of reference pictures wherein, when the reference picture list is to be a modified list, generating the reference picture list by, at least, for each entry in the reference picture list, reading an index into the temporary ordered list of reference pictures and selecting, for the entry in the reference picture list, a reference picture from the temporary ordered list of reference pictures that is identified by the index.

### Claim 19 (depends on 18)

The method of claim 18, further comprising
reading data indicating that the reference picture list is to be the modified list.

### Claim 20 (depends on 19)

The method of claim 19 wherein:
when the reference picture list is not to be the modified list, generating the reference picture list comprises taking entries from the temporary ordered list of reference pictures in order up to a specified number of entries.

### Claim 21 (depends on 19)

The method of claim 19, wherein the index is in a range of zero to a number of pictures in the DPB.

### Claim 22 (depends on 19)

The method of claim 19, wherein the index is specified by a syntax element ref_pic_set_idx.

### Claim 23 (depends on 22)

The method of claim 22, further comprising:
reading a syntax element ref_pic_list_modification_flag_l0,
wherein:
the syntax element ref_pic_list_modification_flag_l0 being equal to a first value specifies that the syntax element ref_pic_set_idx is present for use in generating the reference picture list; and
the syntax element ref_pic_list_modification_flag_l0 being equal to a second value specifies that the syntax element ref_pic_set_idx is not present for use in generating the reference picture list.

### Claim 24 (depends on 23)

The method of claim 23, wherein, if the syntax element ref_pic_set_idx is not present, the index is set to zero.

### Claim 25 (depends on 18)

The method of claim 18, wherein the long term reference pictures are listed in the first temporary ordered list of reference pictures in the order in which the long term reference pictures are stored in the DPB.

### Claim 26

A non-transitory computer readable medium having instructions, which when executed by a computer, enable a method of generating a reference picture list, the method comprising:
generating a temporary ordered list of reference pictures from a decoded picture buffer (DPB), in which the temporary ordered list is ordered with any reference pictures for a current picture that is currently being decoded that are in the DPB and that are temporally before the current picture listed in order by temporal distance from the current picture, followed by any reference pictures for the current picture that are in the DPB and that are temporally later than the current picture listed in order by temporal distance from the current picture, followed by any long term reference pictures for the current picture that are in the DPB; and
generating a reference picture list by selecting reference pictures from the temporary ordered list of reference pictures, wherein, when the reference picture list is to be a modified list, generating the reference picture list by, at least, for each entry in the reference picture list, reading an index into the temporary ordered list of reference pictures and selecting, for the entry in the reference picture list, a reference picture from the temporary ordered list of reference pictures that is identified by the index.

### Claim 27 (depends on 26)

The computer readable medium of claim 26, wherein the method further comprises reading data indicating if the reference picture list is to be the modified list.

### Claim 28 (depends on 26)

The computer readable medium of claim 26, wherein the method further comprises, when the reference picture list is not to be the modified list, generating the reference picture list by taking entries from the temporary ordered list of reference pictures in order up to a first specified number of entries.

### Claim 29 (depends on 26)

The computer readable medium of claim 26, wherein the index is in a range of zero to a number of pictures in the DPB.

### Claim 30 (depends on 26)

The computer readable medium of claim 26, wherein the index is specified by a syntax element ref_pic_set_idx.

### Claim 31 (depends on 30)

The computer readable medium of claim 30, wherein:
the method further comprises reading a syntax element ref_pic_list_modification_flag_l0;
the syntax element ref_pic_list_modification_flag_l0 being equal to a first value specifies that the syntax element ref_pic_set_idx is present for use in generating the reference picture list; and
the syntax element ref_pic_list_modification_flag_l0 being equal to a second value specifies that the syntax element ref_pic_set_idx is not present for use in generating the reference picture list.

### Claim 32 (depends on 30)

The computer readable medium of claim 30, wherein, if the syntax element ref_pic_set_idx is not present, the index is set to zero.

### Claim 33 (depends on 28)

The computer readable medium of claim 28, wherein the long term reference pictures are listed in the temporary ordered list of reference pictures in the order in which the long term reference pictures are stored in the DPB.