DCT
: Discrete Cosine Transform
ADST
: Asymmetric Discrete Sine Transform
LSB
: Least Significant Bit
MSB
: Most Significant Bit
WHT
: Walsh Hadamard Transform
The specification makes use of a number of constant integers. Constants that relate to the semantics of a particular syntax element are defined in [section 6][].
Additional constants are defined below:
| Symbol name | Value | Description |
|---|---|---|
REFS_PER_FRAME |
7 | Number of reference frames that can be used for inter prediction |
TOTAL_REFS_PER_FRAME |
8 | Number of reference frame types (including intra type) |
BLOCK_SIZE_GROUPS |
4 | Number of contexts when decoding y_mode |
BLOCK_SIZES |
22 | Number of different block sizes used |
BLOCK_INVALID |
22 | Sentinel value to mark partition choices that are not allowed |
MAX_SB_SIZE |
128 | Maximum size of a superblock in luma samples |
MI_SIZE |
4 | Smallest size of a mode info block in luma samples |
MI_SIZE_LOG2 |
2 | Base 2 logarithm of smallest size of a mode info block |
MAX_TILE_WIDTH |
4096 | Maximum width of a tile in units of luma samples |
MAX_TILE_AREA |
4096 * 2304 | Maximum area of a tile in units of luma samples |
MAX_TILE_ROWS |
64 | Maximum number of tile rows |
MAX_TILE_COLS |
64 | Maximum number of tile columns |
INTRABC_DELAY_PIXELS |
256 | Number of horizontal luma samples before intra block copy can be used |
INTRABC_DELAY_SB64 |
4 | Number of 64 by 64 blocks before intra block copy can be used |
NUM_REF_FRAMES |
8 | Number of frames that can be stored for future reference |
IS_INTER_CONTEXTS |
4 | Number of contexts for is_inter |
REF_CONTEXTS |
3 | Number of contexts for single_ref, comp_ref, comp_bwdref, uni_comp_ref, uni_comp_ref_p1 and uni_comp_ref_p2 |
MAX_SEGMENTS |
8 | Number of segments allowed in segmentation map |
SEGMENT_ID_CONTEXTS |
3 | Number of contexts for segment_id |
SEG_LVL_ALT_Q |
0 | Index for quantizer segment feature |
SEG_LVL_ALT_LF_Y_V |
1 | Index for vertical luma loop filter segment feature |
SEG_LVL_REF_FRAME |
5 | Index for reference frame segment feature |
SEG_LVL_SKIP |
6 | Index for skip segment feature |
SEG_LVL_GLOBALMV |
7 | Index for global mv feature |
SEG_LVL_MAX |
8 | Number of segment features |
PLANE_TYPES |
2 | Number of different plane types (luma or chroma) |
TX_SIZE_CONTEXTS |
3 | Number of contexts for transform size |
INTERP_FILTERS |
3 | Number of values for interp_filter |
INTERP_FILTER_CONTEXTS |
16 | Number of contexts for interp_filter |
SKIP_MODE_CONTEXTS |
3 | Number of contexts for decoding skip_mode |
SKIP_CONTEXTS |
3 | Number of contexts for decoding skip |
PARTITION_CONTEXTS |
4 | Number of contexts when decoding partition |
TX_SIZES |
5 | Number of square transform sizes |
TX_SIZES_ALL |
19 | Number of transform sizes (including non-square sizes) |
TX_MODES |
3 | Number of values for tx_mode |
DCT_DCT |
0 | Inverse transform rows with DCT and columns with DCT |
ADST_DCT |
1 | Inverse transform rows with DCT and columns with ADST |
DCT_ADST |
2 | Inverse transform rows with ADST and columns with DCT |
ADST_ADST |
3 | Inverse transform rows with ADST and columns with ADST |
FLIPADST_DCT |
4 | Inverse transform rows with DCT and columns with FLIPADST |
DCT_FLIPADST |
5 | Inverse transform rows with FLIPADST and columns with DCT |
FLIPADST_FLIPADST |
6 | Inverse transform rows with FLIPADST and columns with FLIPADST |
ADST_FLIPADST |
7 | Inverse transform rows with FLIPADST and columns with ADST |
FLIPADST_ADST |
8 | Inverse transform rows with ADST and columns with FLIPADST |
IDTX |
9 | Inverse transform rows with identity and columns with identity |
V_DCT |
10 | Inverse transform rows with identity and columns with DCT |
H_DCT |
11 | Inverse transform rows with DCT and columns with identity |
V_ADST |
12 | Inverse transform rows with identity and columns with ADST |
H_ADST |
13 | Inverse transform rows with ADST and columns with identity |
V_FLIPADST |
14 | Inverse transform rows with identity and columns with FLIPADST |
H_FLIPADST |
15 | Inverse transform rows with FLIPADST and columns with identity |
TX_TYPES |
16 | Number of inverse transform types |
MB_MODE_COUNT |
17 | Number of values for YMode |
INTRA_MODES |
13 | Number of values for y_mode |
UV_INTRA_MODES_CFL_NOT_ALLOWED |
13 | Number of values for uv_mode when chroma from luma is not allowed |
UV_INTRA_MODES_CFL_ALLOWED |
14 | Number of values for uv_mode when chroma from luma is allowed |
COMPOUND_MODES |
8 | Number of values for compound_mode |
COMPOUND_MODE_CONTEXTS |
8 | Number of contexts for compound_mode |
COMP_NEWMV_CTXS |
5 | Number of new mv values used when constructing context for compound_mode |
NEW_MV_CONTEXTS |
6 | Number of contexts for new_mv |
ZERO_MV_CONTEXTS |
2 | Number of contexts for zero_mv |
REF_MV_CONTEXTS |
6 | Number of contexts for ref_mv |
DRL_MODE_CONTEXTS |
3 | Number of contexts for drl_mode |
MV_CONTEXTS |
2 | Number of contexts for decoding motion vectors including one for intra block copy |
MV_INTRABC_CONTEXT |
1 | Motion vector context used for intra block copy |
MV_JOINTS |
4 | Number of values for mv_joint |
MV_CLASSES |
11 | Number of values for mv_class |
CLASS0_SIZE |
2 | Number of values for mv_class0_bit |
MV_OFFSET_BITS |
10 | Maximum number of bits for decoding motion vectors |
MAX_LOOP_FILTER |
63 | Maximum value used for loop filtering |
REF_SCALE_SHIFT |
14 | Number of bits of precision when scaling reference frames |
SUBPEL_BITS |
4 | Number of bits of precision when choosing an inter prediction filter kernel |
SUBPEL_MASK |
15 | ( 1 << SUBPEL_BITS ) - 1 |
SCALE_SUBPEL_BITS |
10 | Number of bits of precision when computing inter prediction locations |
MV_BORDER |
128 | Value used when clipping motion vectors |
PALETTE_COLOR_CONTEXTS |
5 | Number of values for color contexts |
PALETTE_MAX_COLOR_CONTEXT_HASH |
8 | Number of mappings between color context hash and color context |
PALETTE_BLOCK_SIZE_CONTEXTS |
7 | Number of values for palette block size |
PALETTE_Y_MODE_CONTEXTS |
3 | Number of values for palette Y plane mode contexts |
PALETTE_UV_MODE_CONTEXTS |
2 | Number of values for palette U and V plane mode contexts |
PALETTE_SIZES |
7 | Number of values for palette_size |
PALETTE_COLORS |
8 | Number of values for palette_color |
PALETTE_NUM_NEIGHBORS |
3 | Number of neighbors considered within palette computation |
DELTA_Q_SMALL |
3 | Value indicating alternative encoding of quantizer index delta values |
DELTA_LF_SMALL |
3 | Value indicating alternative encoding of loop filter delta values |
QM_TOTAL_SIZE |
3344 | Number of values in the quantizer matrix |
MAX_ANGLE_DELTA |
3 | Maximum magnitude of AngleDeltaY and AngleDeltaUV |
DIRECTIONAL_MODES |
8 | Number of directional intra modes |
ANGLE_STEP |
3 | Number of degrees of step per unit increase in AngleDeltaY or AngleDeltaUV. |
TX_SET_TYPES_INTRA |
3 | Number of intra transform set types |
TX_SET_TYPES_INTER |
4 | Number of inter transform set types |
WARPEDMODEL_PREC_BITS |
16 | Internal precision of warped motion models |
IDENTITY |
0 | Warp model is just an identity transform |
TRANSLATION |
1 | Warp model is a pure translation |
ROTZOOM |
2 | Warp model is a rotation + symmetric zoom + translation |
AFFINE |
3 | Warp model is a general affine transform |
GM_ABS_TRANS_BITS |
12 | Number of bits encoded for translational components of global motion models, if part of a ROTZOOM or AFFINE model |
GM_ABS_TRANS_ONLY_BITS |
9 | Number of bits encoded for translational components of global motion models, if part of a TRANSLATION model |
GM_ABS_ALPHA_BITS |
12 | Number of bits encoded for non-translational components of global motion models |
DIV_LUT_PREC_BITS |
14 | Number of fractional bits of entries in divisor lookup table |
DIV_LUT_BITS |
8 | Number of fractional bits for lookup in divisor lookup table |
DIV_LUT_NUM |
257 | Number of entries in divisor lookup table |
MOTION_MODES |
3 | Number of values for motion modes |
SIMPLE |
0 | Use translation or global motion compensation |
OBMC |
1 | Use overlapped block motion compensation |
LOCALWARP |
2 | Use local warp motion compensation |
LEAST_SQUARES_SAMPLES_MAX |
8 | Largest number of samples used when computing a local warp |
LS_MV_MAX |
256 | Largest motion vector difference to include in local warp computation |
WARPEDMODEL_TRANS_CLAMP |
1<<23 | Clamping value used for translation components of warp |
WARPEDMODEL_NONDIAGAFFINE_CLAMP |
1<<13 | Clamping value used for matrix components of warp |
WARPEDPIXEL_PREC_SHIFTS |
1<<6 | Number of phases used in warped filtering |
WARPEDDIFF_PREC_BITS |
10 | Number of extra bits of precision in warped filtering |
GM_ALPHA_PREC_BITS |
15 | Number of fractional bits for sending non-translational warp model coefficients |
GM_TRANS_PREC_BITS |
6 | Number of fractional bits for sending translational warp model coefficients |
GM_TRANS_ONLY_PREC_BITS |
3 | Number of fractional bits used for pure translational warps |
INTERINTRA_MODES |
4 | Number of inter intra modes |
MASK_MASTER_SIZE |
64 | Size of MasterMask array |
SEGMENT_ID_PREDICTED_CONTEXTS |
3 | Number of contexts for segment_id_predicted |
IS_INTER_CONTEXTS |
4 | Number of contexts for is_inter |
FWD_REFS |
4 | Number of syntax elements for forward reference frames |
BWD_REFS |
3 | Number of syntax elements for backward reference frames |
SINGLE_REFS |
7 | Number of syntax elements for single reference frames |
UNIDIR_COMP_REFS |
4 | Number of syntax elements for unidirectional compound reference frames |
COMPOUND_TYPES |
2 | Number of values for compound_type |
CFL_JOINT_SIGNS |
8 | Number of values for cfl_alpha_signs |
CFL_ALPHABET_SIZE |
16 | Number of values for cfl_alpha_u and cfl_alpha_v |
COMP_INTER_CONTEXTS |
5 | Number of contexts for comp_mode |
COMP_REF_TYPE_CONTEXTS |
5 | Number of contexts for comp_ref_type |
CFL_ALPHA_CONTEXTS |
6 | Number of contexts for cfl_alpha_u and cfl_alpha_v |
INTRA_MODE_CONTEXTS |
5 | Number of each of left and above contexts for intra_frame_y_mode |
COMP_GROUP_IDX_CONTEXTS |
6 | Number of contexts for comp_group_idx |
COMPOUND_IDX_CONTEXTS |
6 | Number of contexts for compound_idx |
INTRA_EDGE_KERNELS |
3 | Number of filter kernels for the intra edge filter |
INTRA_EDGE_TAPS |
5 | Number of kernel taps for the intra edge filter |
FRAME_LF_COUNT |
4 | Number of loop filter strength values |
MAX_VARTX_DEPTH |
2 | Maximum depth for variable transform trees |
TXFM_PARTITION_CONTEXTS |
21 | Number of contexts for txfm_split |
REF_CAT_LEVEL |
640 | Bonus weight for close motion vectors |
MAX_REF_MV_STACK_SIZE |
8 | Maximum number of motion vectors in the stack |
MFMV_STACK_SIZE |
3 | Stack size for motion field motion vectors |
MAX_TX_DEPTH |
2 | Maximum times the transform can be split |
WEDGE_TYPES |
16 | Number of directions for the wedge mask process |
FILTER_BITS |
7 | Number of bits used in Wiener filter coefficients |
WIENER_COEFFS |
3 | Number of Wiener filter coefficients to read |
SGRPROJ_PARAMS_BITS |
4 | Number of bits needed to specify self guided filter set |
SGRPROJ_PRJ_SUBEXP_K |
4 | Controls how self guided deltas are read |
SGRPROJ_PRJ_BITS |
7 | Precision bits during self guided restoration |
SGRPROJ_RST_BITS |
4 | Restoration precision bits generated higher than source before projection |
SGRPROJ_MTABLE_BITS |
20 | Precision of mtable division table |
SGRPROJ_RECIP_BITS |
12 | Precision of division by n table |
SGRPROJ_SGR_BITS |
8 | Internal precision bits for core selfguided_restoration |
EC_PROB_SHIFT |
6 | Number of bits to reduce CDF precision during arithmetic coding |
EC_MIN_PROB |
4 | Minimum probability assigned to each symbol during arithmetic coding |
SELECT_SCREEN_CONTENT_TOOLS |
2 | Value that indicates the allow_screen_content_tools syntax element is coded |
SELECT_INTEGER_MV |
2 | Value that indicates the force_integer_mv syntax element is coded |
RESTORATION_TILESIZE_MAX |
256 | Maximum size of a loop restoration tile |
MAX_FRAME_DISTANCE |
31 | Maximum distance when computing weighted prediction |
MAX_OFFSET_WIDTH |
8 | Maximum horizontal offset of a projected motion vector |
MAX_OFFSET_HEIGHT |
0 | Maximum vertical offset of a projected motion vector |
WARP_PARAM_REDUCE_BITS |
6 | Rounding bitwidth for the parameters to the shear process |
NUM_BASE_LEVELS |
2 | Number of quantizer base levels |
COEFF_BASE_RANGE |
12 | The quantizer range above NUM_BASE_LEVELS above which the Exp-Golomb coding process is activated |
BR_CDF_SIZE |
4 | Number of values for coeff_br |
SIG_COEF_CONTEXTS_EOB |
4 | Number of contexts for coeff_base_eob |
SIG_COEF_CONTEXTS_2D |
26 | Context offset for coeff_base for horizontal-only or vertical-only transforms. |
SIG_COEF_CONTEXTS |
42 | Number of contexts for coeff_base |
SIG_REF_DIFF_OFFSET_NUM |
5 | Maximum number of context samples to be used in determining the context index for coeff_base and coeff_base_eob. |
SUPERRES_NUM |
8 | Numerator for upscaling ratio |
SUPERRES_DENOM_MIN |
9 | Smallest denominator for upscaling ratio |
SUPERRES_DENOM_BITS |
3 | Number of bits sent to specify denominator of upscaling ratio |
SUPERRES_FILTER_BITS |
6 | Number of bits of fractional precision for upscaling filter selection |
SUPERRES_FILTER_SHIFTS |
1 << SUPERRES_FILTER_BITS | Number of phases of upscaling filters |
SUPERRES_FILTER_TAPS |
8 | Number of taps of upscaling filters |
SUPERRES_FILTER_OFFSET |
3 | Sample offset for upscaling filters |
SUPERRES_SCALE_BITS |
14 | Number of fractional bits for computing position in upscaling |
SUPERRES_SCALE_MASK |
(1 << 14) - 1 | Mask for computing position in upscaling |
SUPERRES_EXTRA_BITS |
8 | Difference in precision between SUPERRES_SCALE_BITS and SUPERRES_FILTER_BITS |
TXB_SKIP_CONTEXTS |
13 | Number of contexts for all_zero |
EOB_COEF_CONTEXTS |
9 | Number of contexts for eob_extra |
DC_SIGN_CONTEXTS |
3 | Number of contexts for dc_sign |
LEVEL_CONTEXTS |
21 | Number of contexts for coeff_br |
TX_CLASS_2D |
0 | Transform class for transform types performing non-identity transforms in both directions |
TX_CLASS_HORIZ |
1 | Transform class for transforms performing only a horizontal non-identity transform |
TX_CLASS_VERT |
2 | Transform class for transforms performing only a vertical non-identity transform |
REFMVS_LIMIT |
( 1 << 12 ) - 1 | Largest reference MV component that can be saved |
INTRA_FILTER_SCALE_BITS |
4 | Scaling shift for intra filtering process |
INTRA_FILTER_MODES |
5 | Number of types of intra filtering |
COEFF_CDF_Q_CTXS |
4 | Number of selectable context types for the coeff( ) syntax structure |
PRIMARY_REF_NONE |
7 | Value of primary_ref_frame indicating that there is no primary reference frame |
BUFFER_POOL_MAX_SIZE |
10 | Number of frames in buffer pool |
| {:.table .table-sm .table-bordered .table-striped } |