NZ626459B2 - Method and apparatus for intra mode coding - Google Patents
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
- H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
- H04N19/103—Selection of coding mode or of prediction mode
- H04N19/11—Selection of coding mode or of prediction mode among a plurality of spatial predictive coding modes
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
- H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
- H04N19/12—Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
- H04N19/122—Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
- H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
- H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
- H04N19/176—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a block, e.g. a macroblock
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/30—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability
- H04N19/33—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability in the spatial domain
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
- H04N19/593—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving spatial prediction techniques
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- H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
- H04N19/61—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding in combination with predictive coding
Abstract
Disclosed are method and apparatus for predictive Intra coding of a block. The method comprises determining a set of Intra prediction modes and applying predictive Intra coding to a PU (prediction unit) of an image based on one or more neighbouring PUs according a current Intra prediction mode. The current Intra prediction mode is selected from the set of Intra prediction modes. The set of Intra prediction modes is used for PUs corresponding to different block sizes including a 4x4 block size and at least one other block size. current Intra prediction mode is selected from the set of Intra prediction modes. The set of Intra prediction modes is used for PUs corresponding to different block sizes including a 4x4 block size and at least one other block size.
Description
METHOD AND APPARATUS FOR INTRA MODE CODING
CROSS REFERENCE TO RELATED APPLICATIONS
The present invention claims priority to PCT Patent Application, Serial No.
, filed on January 16, 2012, entitled “Intra Mode Coding”. The PCT Patent
Application is hereby incorporated by reference in its entirety.
TECHNICAL FIELD
The present invention relates to video coding. In particular, the present invention relates to
coding techniques associated with Intra prediction.
BACKGROUND
Intra prediction exploits spatial correlation within a picture or within a picture region. In order
to improve coding efficiency, the High-Efficiency Video Coding (HEVC) standard being developed
under the Joint Collaborative Team on Video Coding (JCT-VC) group of video coding experts from
ITU-T Study Group exploits block-based spatial prediction extensively. In HEVC, multiple Intra
prediction modes are used to exploit spatial features and the number of Intra prediction modes
depends on the block size of a Prediction Unit (PU). In HEVC Test Model Version 5.0 (HM-5.0),
the size of the PU for Intra coding can be 64x64, 32x32, 16x16, 8x8, or 4x4. A total of 18 Intra
prediction modes (mode 0 to mode 17) are used for 4x4 PU while 35 Intra modes (mode 0 to mode
34) are used for 8x8, 16x16, 32x32 and 64x64 PU as shown in Fig. 1. The 35 Intra prediction
modes include 33 directional prediction modes, one DC mode and one Planar mode as shown in
Fig. 1. Each Intra prediction mode, except for Intra prediction modes 0 and 3, has an associated
angle as shown in Fig. 2. In HM-5.0, the Intra mode coding first maps the Intra mode index (i.e.,
intraPredMode) to intraPredOrder as shown in Table 1. Then intraPredOrder is mapped to the angle
parameter (i.e., intraPredAngle) as shown in Table 2.
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Table 1.
intraPredMode 0 1 2 3 4 5 6 7 8 9
intraPredOrder - - - - 1 5 13 17 21 29
intraPredMode 10 11 12 13 14 15 16 17 18 19
intraPredOrder 33 3 7 11 15 19 23 27 31 2
intraPredMode 20 21 22 23 24 25 26 27 28 29
intraPredOrder 4 6 8 10 12 14 16 18 20 22
intraPredMode 30 31 32 33 34
intraPredOrder 24 26 28 30 32
Table 2.
intraPredOrder 0 1 2 3 4 5 6 7 8 9
intraPredAngle - -32 -26 -21 -17 -13 -9 -5 -2 -
intraPredOrder 10 11 12 13 14 15 16 17 18 19
intraPredAngle 2 5 9 13 17 21 26 32 -26 -21
intraPredOrder 20 21 22 23 24 25 26 27 28 29
intraPredAngle -17 -13 -9 -5 -2 - 2 5 9 13
intraPredOrder 30 31 32 33
intraPredAngle 17 21 26 32
An alternative to the Intra mode index of Fig. 1 is to label each mode with its respective
physical directions. Fig. 3 illustrates an example of Intra mode labeling, where “h” refers to the
horizontal direction and “v” refers to the vertical direction.
In HM-5.0, the Intra mode coding of luma component comprises two most probable modes
(MPMs) and the remaining modes. The two most probable modes are derived for each PU from the
Intra mode of the above PU and the Intra mode of the left PU. If intraPredMode of the current PU
is equal to either of the most probable modes, a flag prev_intra_pred_flag is set to 1 to indicate that
intraPredMode of the current PU matches one of the most probable modes and the index of the
matched most probable mode is transmitted following the flag. If intraPredMode of the current PU
doesn’t match any of the most probable modes, prev_intra_pred_flag is set to 0 to indicate this case
and rem_intra_luma_pred_mode is transmitted following the flag to signal the index of the
remaining mode matching intraPredMode of the current PU. The binarization of
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rem_intra_luma_pred_mode in CABAC is shown in Table 3 for 4x4 PU and in Table 4 for 8x8,
16x16, 32x32, and 64x64 PUs.
Table 3.
Value of Bin string
rem_intra_luma_pred_mode
less than 16 Fixed Length, 0000~1111
Table 4.
Value of Bin string
rem_intra_luma_pred_mode
less than 31 Fixed Length, 00000~11110
31 111110
32 111111
For 8x8, 16x16, 32x32 and 64x64 PU, there are 33 remaining modes, i.e., 33 possible values of
rem_intra_luma_pred_mode as shown in Table 4. This requires one additional bit for
rem_intra_luma_pred_mode equal to 32 or 33 compared to other remaining modes. This causes the
code length of rem_intra_luma_pred_mode to be non-uniform and additional operations may be
necessary for the corresponding coding process. It is desirable to be able to use fixed length codes
for all remaining Intra prediction modes.
SUMMARY
A method and apparatus of predictive Intra coding of a block are disclosed. In one
embodiment according to the present invention, a same set of Intra prediction modes is used for
PUs corresponding to different block sizes including a 4x4 block size and at least one other block
size. For example, the set of Intra prediction modes is used for 8x8, 16x16, 32x32 and 64x64 PUs
is also used for the 4x4 PU.
In another embodiment of the present invention, the number of Intra prediction modes in the
set is reduced by removing at least one Intra prediction mode from the set. In order to lower the
impact on system performance due to Intra prediction mode removal, the removed Intra prediction
mode is carefully selected. For example, when the set of 35 Intra prediction modes is used,
intraPredMode corresponding to 18, 34, or 26 can be removed without causing any significant
impact on the performance. The current Intra prediction mode can be coded predictively based on
neighboring PUs, wherein the current Intra prediction mode is predicted using 2 most probable
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modes (MPMs) and 32 remaining modes. The 32 remaining modes can be represented using 5-bit
fixed length codes.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 illustrates the 35 Intra prediction modes for High-Efficiency Video Coding (HEVC)
labeled with Intra mode indices.
Fig. 2 illustrates the Intra prediction angles associated with Intra prediction modes for High-
Efficiency Video Coding (HEVC).
Fig. 3 illustrates the 35 Intra prediction modes for High-Efficiency Video Coding (HEVC)
labeled with physical directions.
Fig. 4A illustrates an example of Intra prediction mode reduction by removing “h+6” Intra
prediction mode (i.e., intraPredMode 18) according to an embodiment of the present invention.
Fig. 4B illustrates another example of Intra prediction mode reduction by removing “h+7”
Intra prediction mode (i.e., intraPredMode 34) according to an embodiment of the present
invention.
Fig. 4C illustrates another example of Intra prediction mode reduction by removing “v+7”
Intra prediction mode (i.e., intraPredMode 26) according to an embodiment of the present
invention.
Fig. 5 illustrates an exemplary flowchart for a system sharing Intra prediction modes between
4x4 PUs and PUs of other block sizes according to an embodiment of the present invention.
Fig. 6 illustrates an exemplary flowchart for a system incorporating a reduced set of Intra
prediction modes according to an embodiment of the present invention.
DETAILED DESCRIPTION
As mentioned earlier, in HM-5.0, the 4x4 PU uses 18 Intra prediction modes and the 8x8,
16x16, 32x32 and 64x64 PUs use 35 Intra prediction modes. In other words, the 4x4 PU and larger
PUs use different sets of Intra prediction modes. This situation is the same for other coding systems
as well. For example, in H.264/AVC and RealVideo 8, the 4x4 block uses 9 Intra prediction modes
while the 16x16 block uses 4 Intra prediction modes. In VP8, the 4x4 block uses 10 Intra
prediction modes while the 16x16 block uses 4 Intra prediction modes. The use of different sets of
Intra prediction modes between the 4x4 PU (or block) and other PUs (or blocks) will increase
system complexity. Therefore, an embodiment of the present invention unifies the Intra prediction
modes between the 4x4 PU and PUs having other block sizes. As an example, the 4x4 PU uses the
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same Intra prediction modes as 8x8, 16x16, 32x32 and 64x64 PUs. In this case, instead of 18 Intra
prediction modes, the 4x4 PU may also use the set of 35 Intra prediction modes as the 8x8, 16x16,
32x32 and 64x64 PUs.
In Intra mode coding, more Intra prediction modes will require more bits to represent a
selected Intra prediction mode for a current Intra mode. It is desirable to reduce the number of Intra
prediction modes with negligible performance impact. According to one embodiment of the present
invention, the set of 35 Intra prediction modes is reduced to a set of 34 Intra prediction modes. By
examining the 35 Intra prediction modes shown in Fig. 1 and Fig. 3, it is noticed that neither Intra
prediction mode 18 (i.e., “h+6”) nor Intra prediction mode 34 (i.e., “h+7”) is included in the
original set of 18 Intra prediction modes for the 4x4 PU. Therefore, either Intra prediction mode 18
(i.e., “h+6”) or Intra prediction mode 34 (i.e., “h+7”) can be removed from the set of 35 Intra
prediction modes according to one embodiment.
Upon removal of an Intra prediction mode from the set of 35 Intra prediction modes, the
mapping between the Intra mode indexes (i.e., intraPredMode) and intraPredOrder has to be
modified accordingly and an example of modified mapping is shown in Table 5 (intraPredMode 18
removal) and Table 6 (intraPredMode 34 removal). Similarly, the mapping between intraPredOrder
and the angle parameters (i.e., intraPredAngle) has to be modified as well and an example of the
modified mapping is shown in Table 7 (intraPredMode 18 removal) and Table 8 (intraPredMode 34
removal). In HM-5.0, the current Intra prediction mode is coded using predictive coding based on
the 2 most probable modes (MPMs) and remaining modes. When the 2 most probable modes are
used, there will be 32 remaining modes after one Intra prediction mode is removed. The
binarization of the 32 remaining modes for CABAC can be done using 5-bit fixed length codes as
shown in Table 9. In tables 5 through 8, the “*” symbol indicates that there is no corresponding
mapping element.
While the mapping between intraPredMode and intraPredOrder can be represent in a table
form as shown in Tables 5 and 6, the mapping may also be represented in an ordered set form. For
example, Table 5 can be represented by the ordered set {*, *, *, *, 1, 5, 13, 17, 21, 29, 32, 3, 7, 11,
, 19, 23, 27, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 31}, wherein the first 4 ordered
elements (i.e., “*,*,*,*” ) correspond to intraPredMode = 0, 1, 2 and 3 respectively. The fifth
ordered element (i.e., “1”) correspond to intraPredMode=4, and so on. Similarly, Table 6 can be
represented by the ordered set {*, *, *, *, 1, 5, 13, 17, 21, 29, 32, 3, 7, 11, 15, 19, 23, 27, 31, 2, 4, 6,
8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30}.
The ordered set representation can also be applied to the mapping between intraPredOrder and
intraPredAngle as shown in Tables 7 and 8. Accordingly, Table 7 can be represented by the
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ordered set {*, -32, -26, -21, -17, -13, -9, -5, -2, *,2, 5, 9, 13, 17, 21, 26, 32, -26, -21, -17, -13, -9, -
, -2, *, 2, 5, 9, 13, 17, 26, 32} and Table 8 can be represented by the ordered set {*, -32, -26, -21, -
17, -13, -9, -5, -2, *,2, 5, 9, 13, 17, 21, 26, 32, -26, -21, -17, -13, -9, -5, -2, *, 2, 5, 9, 13, 17, 21, 32}.
Table 5.
intraPredMode 0 1 2 3 4 5 6 7 8 9
intraPredOrder * * * * 1 5 13 17 21 29
intraPredMode 10 11 12 13 14 15 16 17 18 19
intraPredOrder 32 3 7 11 15 19 23 27 2 4
intraPredMode 20 21 22 23 24 25 26 27 28 29
intraPredOrder
6 8 10 12 14 16 18 20 22 24
intraPredMode 30 31 32 33
intraPredOrder 26 28 30 31
Table 6.
intraPredMode 0 1 2 3 4 5 6 7 8 9
intraPredOrder * * * * 1 5 13 17 21 29
intraPredMode 10 11 12 13 14 15 16 17 18 19
intraPredOrder 31 2
32 3 7 11 15 19 23 27
intraPredMode 20 21 22 23 24 25 26 27 28 29
intraPredOrder 4 6 8 10 12 14 16 18 20 22
intraPredMode 30 31 32 33
intraPredOrder 24 26 28 30
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Table 7.
intraPredOrder 0 1 2 3 4 5 6 7 8 9
intraPredAngle * -32 -26 -21 -17 -13 -9 -5 -2 *
intraPredOrder 10 11 12 13 14 15 16 17 18 19
intraPredAngle 2 5 9 13 17 21 26 32 -26 -21
intraPredOrder 20 21 22 23 24 25 26 27 28 29
intraPredAngle -17 -13 -9 -5 -2 * 2 5 9 13
intraPredOrder 30 31 32
intraPredAngle 17 26 32
Table 8.
intraPredOrder 0 1 2 3 4 5 6 7 8 9
intraPredAngle * -32 -26 -21 -17 -13 -9 -5 -2 *
intraPredOrder 10 11 12 13 14 15 16 17 18 19
intraPredAngle 2 5 9 13 17 21 26 32 -26 -21
intraPredOrder 20 21 22 23 24 25 26 27 28 29
intraPredAngle -17 -13 -9 -5 -2 * 2 5 9 13
intraPredOrder 30 31 32
intraPredAngle 17 21 32
Table 9.
Value of Bin string
rem_intra_luma_pred_mode
less than 32 Fixed Length, 00000~11110
While removal of Intra prediction mode 18 or 34 is used in the above examples as a means to
reduce the number of Intra prediction modes, other Intra prediction mode may be selected for
removal as well. For example, Intra prediction mode 26 can be removed and an example of
modified mapping between the Intra mode indexes (i.e., intraPredMode) and intraPredOrder is
shown in Table 10 and an example of modified mapping between the intraPredOrder and the angle
parameters (i.e., intraPredAngle) is shown in Table 11.
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Table 10.
intraPredMode 0 1 2 3 4 5 6 7 8 9
intraPredOrder * * * * 1 5 13 16 20 28
intraPredMode 10 11 12 13 14 15 16 17 18 19
intraPredOrder
32 3 7 11 15 18 22 26 30 2
intraPredMode 20 21 22 23 24 25 26 27 28 29
intraPredOrder 4 6 8 10 12 14 17 19 21 23
intraPredMode 30 31 32 33
intraPredOrder
27 29 31
Table 11.
intraPredOrder 0 1 2 3 4 5 6 7 8 9
intraPredAngle * -32 -26 -21 -17 -13 -9 -5 -2 *
intraPredOrder 10 11 12 13 14 15 16 17 18 19
intraPredAngle 2 5 9 13 17 21 32 -26 -21 -17
intraPredOrder 20 21 22 23 24 25 26 27 28 29
intraPredAngle -13 -9 -5 -2 * 2 5 9 13 17
intraPredOrder 30 31 32
intraPredAngle 21 26 32
The ordered set representation for Table 10 is {*, *, *, *, 1, 5, 13, 16, 20, 28, 32, 3, 7, 11, 15,
18, 22, 26, 30, 2, 4, 6, 8, 10, 12, 14, 17, 19, 21, 23, 25, 27, 29, 31} and the ordered set
representation for Table 11 is {*, -32, -26, -21, -17, -13, -9, -5, -2, *, 2, 5, 9, 13, 17, 21, 32, -26, -21,
-17, -13, -9, -5, -2, *, 2, 5, 9, 13, 17, 21, 26, 32}.
The performance of a coding system incorporating an embodiment of the present invention is
compared with a reference system based on HEVC system without reduced number of Intra
prediction modes. The performance is measured in terms of BD rate, where a negative value
implies performance improvement over the reference system. The BD rate comparison is
performed by adjusting coding parameters so that the underlying systems result in about the same
objective quality. The performance results are shown in Table 12 for the case where Intra
prediction mode 18 (i.e., “h+6”) is removed. In Table 12, HE refers to High Efficiency coding
configuration. Classes A through E refer to different sets of test video. As shown in Table 12, the
impact on performance in terms of BD rate for Y, U and V components is very small. The
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performance results are shown in Table 13 for the case where Intra prediction mode 34 (i.e., “h+7”)
is removed. Again, the impact on performance is very small.
Table 12.
All Intra HE
Y U V
0.13% 0.12% 0.12%
Class A
0.01% 0.04% 0.01%
Class B
0.04% 0.05% 0.05%
Class C
0.03% 0.04% -0.02%
Class D
0.04% 0.03% 0.03%
Class E
0.05% 0.06% 0.04%
Overall
Enc Time[%] 100%
Dec Time[%] 100%
Table 13.
All Intra HE
Y U V
0.04% 0.01% 0.03%
Class A
0.01% 0.00% 0.02%
Class B
0.03% 0.02% 0.01%
Class C
0.01% 0.02% 0.01%
Class D
0.02% 0.15% 0.04%
Class E
0.02% 0.03% 0.02%
Overall
Enc Time[%] 100%
Dec Time[%] 100%
When a system adopts a unified set of Intra prediction modes for the 4x4 PU and PUs of other
sizes, both the encoder side and the decoder side will use this unified set. Fig. 5 illustrates an
exemplary flowchart of a coding system that shares the same set of Intra prediction modes between
4x4 PUs and PUs having other block sizes. A set of Intra prediction modes is determined in step
510. For a video encoder, the set of Intra prediction modes may be determined according to a pre-
defined set. For example, the set with 35 Intra prediction modes as defined in HM-5.0 may be used.
For a video decoder, the set of Intra prediction modes may also be determined according to a pre-
defined set. Alternatively, a video encoder may use a set of Intra prediction modes of its own and
convey the information in the bitstream. In this case, the decoder can determine the set of Intra
prediction modes from the received bitstream. The predictive Intra coding is then applied to a PU
of an image based on one or more neighboring PUs according to a current Intra prediction mode as
shown in step 520, wherein the current Intra prediction mode is selected from the set of Intra
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prediction modes, and wherein the set of Intra prediction modes is used for PUs corresponding to
different block sizes including a 4x4 block size and at least one other block size. The predictive
Intra coding may correspond to predictive Intra encoding for a video encoder or predictive Intra
decoding for a video decoder. For a video encoder, the current Intra prediction mode may be
selected according to a performance criterion, such as minimal RD rate. The current Intra
prediction mode may be selected in a predictive fashion. Information related to the current Intra
prediction mode may have to be incorporated in the bitstream so that a decoder may derive the same
information. For a video decoder, the current Intra prediction mode may be derived from the
bitstream or inferred from coding conditions.
When a system uses a set of reduced number of Intra prediction modes, the reduced set will be
used in the encoder as well as the decoder so that the system can operate properly. Fig. 6 illustrates
an exemplary flowchart for a coding system that uses a reduced set of Intra prediction modes. A
reduced set of Intra prediction modes is determined in step 610, wherein the reduced set of Intra
prediction modes is derived from an original set of Intra prediction modes by removing at least one
Intra prediction mode from the original set of Intra prediction modes. At a video encoder side, the
encoder may determine the reduced set according to one pre-defined set. The encoder may also
select a reduced set of its own. The information regarding the reduced set may have to be
incorporated in the bitstream so that a decoder may derive the same information. The predictive
Intra coding is then applied to a PU of an image based on one or more neighboring PUs according a
current Intra prediction mode as shown in step 620, wherein the current Intra prediction mode is
selected from the reduced set of Intra prediction modes. Again, for a video encoder, the current
Intra prediction mode may be selected according to a performance criterion, such as minimal RD
rate. The current Intra prediction mode may be selected in a predictive fashion. Information related
to the current Intra prediction mode may have to be incorporated in the bitstream so that a decoder
may derive the same information. For a video decoder, the current Intra prediction mode may be
derived from the bitstream or inferred from coding conditions.
The flowcharts shown in Fig. 5 and Fig. 6 are intended for serving as examples of sharing a set
of Intra prediction modes and using a reduced set of Intra prediction modes according to
embodiments of the present invention. A person skilled in the art may practice the present
invention by modifying individual steps, splitting or combining steps with departing from the spirit
of the present invention.
The above description is presented to enable a person of ordinary skill in the art to practice the
present invention as provided in the context of a particular application and its requirement. Various
modifications to the described embodiments will be apparent to those with skill in the art, and the
206583NZ_spec_20150708_PLH
general principles defined herein may be applied to other embodiments. Therefore, the present
invention is not intended to be limited to the particular embodiments shown and described, but is to
be accorded the widest scope consistent with the principles and novel features herein disclosed. In
the above detailed description, various specific details are illustrated in order to provide a thorough
understanding of the present invention. Nevertheless, it will be understood by those skilled in the
art that the present invention may be practiced.
Embodiment of the present invention as described above may be implemented in various
hardware, software codes, or a combination of both. For example, an embodiment of the present
invention can be a circuit integrated into a video compression chip or program code integrated into
video compression software to perform the processing described herein. An embodiment of the
present invention may also be program code to be executed on a Digital Signal Processor (DSP) to
perform the processing described herein. The invention may also involve a number of functions to
be performed by a computer processor, a digital signal processor, a microprocessor, or field
programmable gate array (FPGA). These processors can be configured to perform particular tasks
according to the invention, by executing machine-readable software code or firmware code that
defines the particular methods embodied by the invention. The software code or firmware code
may be developed in different programming languages and different formats or styles. The
software code may also be compiled for different target platforms. However, different code
formats, styles and languages of software codes and other means of configuring code to perform the
tasks in accordance with the invention will not depart from the spirit and scope of the invention.
The invention may be embodied in other specific forms without departing from its spirit or
essential characteristics. The described examples are to be considered in all respects only as
illustrative and not restrictive. The scope of the invention is therefore, indicated by the appended
claims rather than by the foregoing description. All changes which come within the meaning and
range of equivalency of the claims are to be embraced within their scope.
206583NZ_spec_20150708_PLH
Claims (8)
1. A method for predictive Intra coding of a block, the method comprising: determining a set of Intra prediction modes; and applying predictive Intra coding to a PU (prediction unit) of an image based on one or more neighboring PUs according a current Intra prediction mode, wherein the current Intra prediction mode is selected from the set of Intra prediction modes, and wherein the set of Intra prediction modes is used for PUs corresponding to different block sizes including a 4x4 block size and at least one other block size.
2. The method of Claim 1, wherein said at least one other block size includes 8x8, 16x16, 32x32 and 64x64.
3. The method of Claim 1, wherein the set of Intra prediction modes contains 35 Intra prediction modes.
4. The method of Claim 1, wherein the set of Intra prediction modes is used for PUs corresponding to all block sizes.
5. An apparatus for predictive Intra coding of a block, the apparatus comprising: means for determining a set of Intra prediction modes; and means for applying predictive Intra coding to a PU (prediction unit) of an image based on one or more neighboring PUs according a current Intra prediction mode, wherein the current Intra prediction mode is selected from the set of Intra prediction modes, and wherein the set of Intra prediction modes is used for PUs corresponding to different block sizes including a 4x4 block size and at least one other block size.
6. The apparatus of Claim 5, wherein said at least one other block size includes 8x8, 16x16, 32x32 and 64x64.
7. The apparatus of Claim 5, wherein the set of Intra prediction modes contains 35 Intra prediction modes.
8. The apparatus of Claim 5, wherein the set of Intra prediction modes is used for PUs corresponding to all block sizes. 206583NZ_spec_20150708_PLH
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NZ709833A NZ709833B2 (en) | 2012-01-16 | 2012-12-28 | Method and apparatus for intra mode coding |
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PCT/CN2012/070425 WO2013106986A1 (en) | 2012-01-16 | 2012-01-16 | Methods and apparatuses of intra mode coding |
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PCT/CN2012/087887 WO2013107270A1 (en) | 2012-01-16 | 2012-12-28 | Method and apparatus for intra mode coding |
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