H.264 CABAC initial values

At the start of every slice coded with CABAC (and after each I_PCM macroblock), each of the 1024 context variables is set from a pair of numbers (m, n) and the slice QP. This page lists the pairs for ctxIdx 0 to 459, which cover every syntax element except the separate Cb and Cr contexts of 4:4:4 coding (ctxIdx 460 to 1023). I and SI slices have one set of values; P, SP and B slices have three, chosen by cabac_init_idc in the slice header. Source: ITU-T H.264 (06/2026, version 16), clause 9.3.1.1, Tables 9-11 to 9-24 and 9-34.

From (m, n) to a context state

preCtxState = Clip3(1, 126, ((m × Clip3(0, 51, SliceQPY)) >> 4) + n)
if preCtxState <= 63:  pStateIdx = 63 − preCtxState,  valMPS = 0
else:                  pStateIdx = preCtxState − 64,  valMPS = 1

ctxIdx 276 is not initialised from a table: it serves end_of_slice_flag and the I_PCM bin of mb_type and is decoded with DecodeTerminate. A decoder that uses the ordinary decision process for it sets pStateIdx 63 (a state that never adapts) and valMPS 0.

Which contexts each slice type uses

Table 9-11. “na” means the element does not occur in that slice type.

Syntax element	SI	I	P, SP	B
`mb_type`	0–10	3–10	14–20	27–35
`mb_skip_flag`			11–13	24–26
`sub_mb_type`			21–23	36–39
`mvd_l0`, `mvd_l1` horizontal			40–46 (l0 only)	40–46
`mvd_l0`, `mvd_l1` vertical			47–53 (l0 only)	47–53
`ref_idx_l0`, `ref_idx_l1`			54–59 (l0 only)	54–59
`mb_qp_delta`	60–63	60–63	60–63	60–63
`intra_chroma_pred_mode`	64–67	64–67	64–67	64–67
`prev_intra4x4_pred_mode_flag`, `prev_intra8x8_pred_mode_flag`	68 (4 × 4 only)	68	68	68
`rem_intra4x4_pred_mode`, `rem_intra8x8_pred_mode`	69 (4 × 4 only)	69	69	69
`mb_field_decoding_flag`	70–72	70–72	70–72	70–72
`coded_block_pattern` luma, chroma	73–76, 77–84	73–76, 77–84	73–76, 77–84	73–76, 77–84
`coded_block_flag`	85–104	85–104, 460–483, 1012–1023
`significant_coeff_flag`	105–165, 277–337	105–165, 277–337, 402–416, 436–450, 484–571, 776–863, 660–689, 718–747
`last_significant_coeff_flag`	166–226, 338–398	166–226, 338–398, 417–425, 451–459, 572–659, 864–951, 690–707, 748–765
`coeff_abs_level_minus1`	227–275	227–275, 426–435, 952–1011, 708–717, 766–775
`transform_size_8x8_flag`	na	399–401	399–401	399–401

The context offsets of each element (Table 9-34): mb_type SI prefix 0, suffix 3; I 3; mb_skip_flag P 11, B 24; mb_type P prefix 14, suffix 17; B prefix 27, suffix 32; sub_mb_type P 21, B 36; mvd 40 and 47; ref_idx 54; mb_qp_delta 60; intra_chroma_pred_mode 64; prev_intra_pred_mode_flag 68; rem_intra_pred_mode 69; mb_field_decoding_flag 70; coded_block_pattern prefix 73, suffix 77; coded_block_flag 85; significant_coeff_flag frame 105, field 277; last_significant_coeff_flag frame 166, field 338; coeff_abs_level_minus1 227; end_of_slice_flag 276; transform_size_8x8_flag 399; for 8 × 8 luma blocks (ctxBlockCat 5) significant frame 402, last frame 417, level 426, significant field 436, last field 451. The offsets for Cb and Cr blocks are on the 4:4:4 page.

mb_type, mb_skip_flag and sub_mb_type

ctxIdx 0 to 10 (Table 9-12) have one set of values, used in SI slices (0 to 10) and I slices (3 to 10).

ctxIdx	0	1	2	3	4	5	6	7	8	9	10
m	20	2	3	20	2	3	−28	−23	−6	−1	7
n	−15	54	74	−15	54	74	127	104	53	54	51

ctxIdx 11 to 39 (Tables 9-13 and 9-14) occur only in P, SP and B slices: 11 to 13 mb_skip_flag (P), 14 to 20 mb_type (P), 21 to 23 sub_mb_type (P), 24 to 26 mb_skip_flag (B), 27 to 35 mb_type (B), 36 to 39 sub_mb_type (B).

ctxIdx	cabac_init_idc 0		1		2
ctxIdx	m	n	m	n	m	n
11	23	33	22	25	29	16
12	23	2	34	0	25	0
13	21	0	16	0	14	0
14	1	9	−2	9	−10	51
15	0	49	4	41	−3	62
16	−37	118	−29	118	−27	99
17	5	57	2	65	26	16
18	−13	78	−6	71	−4	85
19	−11	65	−13	79	−24	102
20	1	62	5	52	5	57
21	12	49	9	50	6	57
22	−4	73	−3	70	−17	73
23	17	50	10	54	14	57
24	18	64	26	34	20	40
25	9	43	19	22	20	10
26	29	0	40	0	29	0
27	26	67	57	2	54	0
28	16	90	41	36	37	42
29	9	104	26	69	12	97
30	−46	127	−45	127	−32	127
31	−20	104	−15	101	−22	117
32	1	67	−4	76	−2	74
33	−13	78	−6	71	−4	85
34	−11	65	−13	79	−24	102
35	1	62	5	52	5	57
36	−6	86	6	69	−6	93
37	−17	95	−13	90	−14	88
38	−6	61	0	52	−6	44
39	9	45	8	43	4	55

mvd_l0 and mvd_l1

ctxIdx 40 to 46 for the horizontal component, 47 to 53 for the vertical (Table 9-15). Only P, SP and B slices.

ctxIdx	cabac_init_idc 0		1		2
ctxIdx	m	n	m	n	m	n
40	−3	69	−2	69	−11	89
41	−6	81	−5	82	−15	103
42	−11	96	−10	96	−21	116
43	6	55	2	59	19	57
44	7	67	2	75	20	58
45	−5	86	−3	87	4	84
46	2	88	−3	100	6	96
47	0	58	1	56	1	63
48	−3	76	−3	74	−5	85
49	−10	94	−6	85	−13	106
50	5	54	0	59	5	63
51	4	69	−3	81	6	75
52	−3	81	−7	86	−3	90
53	0	88	−5	95	−1	101

ref_idx and transform_size_8x8_flag

ctxIdx 54 to 59 ref_idx_l0 and ref_idx_l1; 399 to 401 transform_size_8x8_flag (Table 9-16).

ctxIdx	I slices		cabac_init_idc 0		1		2
ctxIdx	m	n	m	n	m	n	m	n
54	na	na	−7	67	−1	66	3	55
55	na	na	−5	74	−1	77	−4	79
56	na	na	−4	74	1	70	−2	75
57	na	na	−5	80	−2	86	−12	97
58	na	na	−7	72	−5	72	−7	50
59	na	na	1	58	0	61	1	60
399	31	21	12	40	25	32	21	33
400	31	31	11	51	21	49	19	50
401	25	50	14	59	21	54	17	61

mb_qp_delta and intra prediction modes

ctxIdx 60 to 63 mb_qp_delta, 64 to 67 intra_chroma_pred_mode, 68 the prev_intra…_pred_mode_flag and 69 rem_intra…_pred_mode. One set for all slice types (Table 9-17).

ctxIdx	60	61	62	63	64	65	66	67	68	69
m	0	0	0	0	−9	4	0	−7	13	3
n	41	63	63	63	83	86	97	72	41	62

mb_field_decoding_flag, coded_block_pattern and coded_block_flag

ctxIdx 70 to 72 mb_field_decoding_flag, 73 to 76 the luma part of coded_block_pattern, 77 to 84 its chroma part, 85 to 104 coded_block_flag for ctxBlockCat 0 to 4 (Table 9-18).

ctxIdx	I and SI		cabac_init_idc 0		1		2
ctxIdx	m	n	m	n	m	n	m	n
70	0	11	0	45	13	15	7	34
71	1	55	−4	78	7	51	−9	88
72	0	69	−3	96	2	80	−20	127
73	−17	127	−27	126	−39	127	−36	127
74	−13	102	−28	98	−18	91	−17	91
75	0	82	−25	101	−17	96	−14	95
76	−7	74	−23	67	−26	81	−25	84
77	−21	107	−28	82	−35	98	−25	86
78	−27	127	−20	94	−24	102	−12	89
79	−31	127	−16	83	−23	97	−17	91
80	−24	127	−22	110	−27	119	−31	127
81	−18	95	−21	91	−24	99	−14	76
82	−27	127	−18	102	−21	110	−18	103
83	−21	114	−13	93	−18	102	−13	90
84	−30	127	−29	127	−36	127	−37	127
85	−17	123	−7	92	0	80	11	80
86	−12	115	−5	89	−5	89	5	76
87	−16	122	−7	96	−7	94	2	84
88	−11	115	−13	108	−4	92	5	78
89	−12	63	−3	46	0	39	−6	55
90	−2	68	−1	65	0	65	4	61
91	−15	84	−1	57	−15	84	−14	83
92	−13	104	−9	93	−35	127	−37	127
93	−3	70	−3	74	−2	73	−5	79
94	−8	93	−9	92	−12	104	−11	104
95	−10	90	−8	87	−9	91	−11	91
96	−30	127	−23	126	−31	127	−30	127
97	−1	74	5	54	3	55	0	65
98	−6	97	6	60	7	56	−2	79
99	−7	91	6	59	7	55	0	72
100	−20	127	6	69	8	61	−4	92
101	−4	56	−1	48	−3	53	−6	56
102	−5	82	0	68	0	68	3	68
103	−7	76	−4	69	−7	74	−8	71
104	−22	125	−8	88	−9	88	−13	98

significant_coeff_flag, frame coded

ctxIdx 105 to 165, for blocks with ctxBlockCat 0 to 4 in frame macroblocks (Table 9-19).

ctxIdx	I and SI		cabac_init_idc 0		1		2
ctxIdx	m	n	m	n	m	n	m	n
105	−7	93	−2	85	−13	103	−4	86
106	−11	87	−6	78	−13	91	−12	88
107	−3	77	−1	75	−9	89	−5	82
108	−5	71	−7	77	−14	92	−3	72
109	−4	63	2	54	−8	76	−4	67
110	−4	68	5	50	−12	87	−8	72
111	−12	84	−3	68	−23	110	−16	89
112	−7	62	1	50	−24	105	−9	69
113	−7	65	6	42	−10	78	−1	59
114	8	61	−4	81	−20	112	5	66
115	5	56	1	63	−17	99	4	57
116	−2	66	−4	70	−78	127	−4	71
117	1	64	0	67	−70	127	−2	71
118	0	61	2	57	−50	127	2	58
119	−2	78	−2	76	−46	127	−1	74
120	1	50	11	35	−4	66	−4	44
121	7	52	4	64	−5	78	−1	69
122	10	35	1	61	−4	71	0	62
123	0	44	11	35	−8	72	−7	51
124	11	38	18	25	2	59	−4	47
125	1	45	12	24	−1	55	−6	42
126	0	46	13	29	−7	70	−3	41
127	5	44	13	36	−6	75	−6	53
128	31	17	−10	93	−8	89	8	76
129	1	51	−7	73	−34	119	−9	78
130	7	50	−2	73	−3	75	−11	83
131	28	19	13	46	32	20	9	52
132	16	33	9	49	30	22	0	67
133	14	62	−7	100	−44	127	−5	90
134	−13	108	9	53	0	54	1	67
135	−15	100	2	53	−5	61	−15	72
136	−13	101	5	53	0	58	−5	75
137	−13	91	−2	61	−1	60	−8	80
138	−12	94	0	56	−3	61	−21	83
139	−10	88	0	56	−8	67	−21	64
140	−16	84	−13	63	−25	84	−13	31
141	−10	86	−5	60	−14	74	−25	64
142	−7	83	−1	62	−5	65	−29	94
143	−13	87	4	57	5	52	9	75
144	−19	94	−6	69	2	57	17	63
145	1	70	4	57	0	61	−8	74
146	0	72	14	39	−9	69	−5	35
147	−5	74	4	51	−11	70	−2	27
148	18	59	13	68	18	55	13	91
149	−8	102	3	64	−4	71	3	65
150	−15	100	1	61	0	58	−7	69
151	0	95	9	63	7	61	8	77
152	−4	75	7	50	9	41	−10	66
153	2	72	16	39	18	25	3	62
154	−11	75	5	44	9	32	−3	68
155	−3	71	4	52	5	43	−20	81
156	15	46	11	48	9	47	0	30
157	−13	69	−5	60	0	44	1	7
158	0	62	−1	59	0	51	−3	23
159	0	65	0	59	2	46	−21	74
160	21	37	22	33	19	38	16	66
161	−15	72	5	44	−4	66	−23	124
162	9	57	14	43	15	38	17	37
163	16	54	−1	78	12	42	44	−18
164	0	62	0	60	9	34	50	−34
165	12	72	9	69	0	89	−22	127

last_significant_coeff_flag, frame coded

ctxIdx 166 to 226 (Table 9-20).

ctxIdx	I and SI		cabac_init_idc 0		1		2
ctxIdx	m	n	m	n	m	n	m	n
166	24	0	11	28	4	45	4	39
167	15	9	2	40	10	28	0	42
168	8	25	3	44	10	31	7	34
169	13	18	0	49	33	−11	11	29
170	15	9	0	46	52	−43	8	31
171	13	19	2	44	18	15	6	37
172	10	37	2	51	28	0	7	42
173	12	18	0	47	35	−22	3	40
174	6	29	4	39	38	−25	8	33
175	20	33	2	62	34	0	13	43
176	15	30	6	46	39	−18	13	36
177	4	45	0	54	32	−12	4	47
178	1	58	3	54	102	−94	3	55
179	0	62	2	58	0	0	2	58
180	7	61	4	63	56	−15	6	60
181	12	38	6	51	33	−4	8	44
182	11	45	6	57	29	10	11	44
183	15	39	7	53	37	−5	14	42
184	11	42	6	52	51	−29	7	48
185	13	44	6	55	39	−9	4	56
186	16	45	11	45	52	−34	4	52
187	12	41	14	36	69	−58	13	37
188	10	49	8	53	67	−63	9	49
189	30	34	−1	82	44	−5	19	58
190	18	42	7	55	32	7	10	48
191	10	55	−3	78	55	−29	12	45
192	17	51	15	46	32	1	0	69
193	17	46	22	31	0	0	20	33
194	0	89	−1	84	27	36	8	63
195	26	−19	25	7	33	−25	35	−18
196	22	−17	30	−7	34	−30	33	−25
197	26	−17	28	3	36	−28	28	−3
198	30	−25	28	4	38	−28	24	10
199	28	−20	32	0	38	−27	27	0
200	33	−23	34	−1	34	−18	34	−14
201	37	−27	30	6	35	−16	52	−44
202	33	−23	30	6	34	−14	39	−24
203	40	−28	32	9	32	−8	19	17
204	38	−17	31	19	37	−6	31	25
205	33	−11	26	27	35	0	36	29
206	40	−15	26	30	30	10	24	33
207	41	−6	37	20	28	18	34	15
208	38	1	28	34	26	25	30	20
209	41	17	17	70	29	41	22	73
210	30	−6	1	67	0	75	20	34
211	27	3	5	59	2	72	19	31
212	26	22	9	67	8	77	27	44
213	37	−16	16	30	14	35	19	16
214	35	−4	18	32	18	31	15	36
215	38	−8	18	35	17	35	15	36
216	38	−3	22	29	21	30	21	28
217	37	3	24	31	17	45	25	21
218	38	5	23	38	20	42	30	20
219	42	0	18	43	18	45	31	12
220	35	16	20	41	27	26	27	16
221	39	22	11	63	16	54	24	42
222	14	48	9	59	7	66	0	93
223	27	37	9	64	16	56	14	56
224	21	60	−1	94	11	73	15	57
225	12	68	−2	89	10	67	26	38
226	2	97	−9	108	−10	116	−24	127

coeff_abs_level_minus1

ctxIdx 227 to 275, for blocks with ctxBlockCat 0 to 4 (Table 9-21).

ctxIdx	I and SI		cabac_init_idc 0		1		2
ctxIdx	m	n	m	n	m	n	m	n
227	−3	71	−6	76	−23	112	−24	115
228	−6	42	−2	44	−15	71	−22	82
229	−5	50	0	45	−7	61	−9	62
230	−3	54	0	52	0	53	0	53
231	−2	62	−3	64	−5	66	0	59
232	0	58	−2	59	−11	77	−14	85
233	1	63	−4	70	−9	80	−13	89
234	−2	72	−4	75	−9	84	−13	94
235	−1	74	−8	82	−10	87	−11	92
236	−9	91	−17	102	−34	127	−29	127
237	−5	67	−9	77	−21	101	−21	100
238	−5	27	3	24	−3	39	−14	57
239	−3	39	0	42	−5	53	−12	67
240	−2	44	0	48	−7	61	−11	71
241	0	46	0	55	−11	75	−10	77
242	−16	64	−6	59	−15	77	−21	85
243	−8	68	−7	71	−17	91	−16	88
244	−10	78	−12	83	−25	107	−23	104
245	−6	77	−11	87	−25	111	−15	98
246	−10	86	−30	119	−28	122	−37	127
247	−12	92	1	58	−11	76	−10	82
248	−15	55	−3	29	−10	44	−8	48
249	−10	60	−1	36	−10	52	−8	61
250	−6	62	1	38	−10	57	−8	66
251	−4	65	2	43	−9	58	−7	70
252	−12	73	−6	55	−16	72	−14	75
253	−8	76	0	58	−7	69	−10	79
254	−7	80	0	64	−4	69	−9	83
255	−9	88	−3	74	−5	74	−12	92
256	−17	110	−10	90	−9	86	−18	108
257	−11	97	0	70	2	66	−4	79
258	−20	84	−4	29	−9	34	−22	69
259	−11	79	5	31	1	32	−16	75
260	−6	73	7	42	11	31	−2	58
261	−4	74	1	59	5	52	1	58
262	−13	86	−2	58	−2	55	−13	78
263	−13	96	−3	72	−2	67	−9	83
264	−11	97	−3	81	0	73	−4	81
265	−19	117	−11	97	−8	89	−13	99
266	−8	78	0	58	3	52	−13	81
267	−5	33	8	5	7	4	−6	38
268	−4	48	10	14	10	8	−13	62
269	−2	53	14	18	17	8	−6	58
270	−3	62	13	27	16	19	−2	59
271	−13	71	2	40	3	37	−16	73
272	−10	79	0	58	−1	61	−10	76
273	−12	86	−3	70	−5	73	−13	86
274	−13	90	−6	79	−1	70	−9	83
275	−14	97	−8	85	−4	78	−10	87

significant_coeff_flag, field coded

ctxIdx 277 to 337, for blocks with ctxBlockCat 0 to 4 in field macroblocks or field pictures (Table 9-22).

ctxIdx	I and SI		cabac_init_idc 0		1		2
ctxIdx	m	n	m	n	m	n	m	n
277	−6	93	−13	106	−21	126	−22	127
278	−6	84	−16	106	−23	124	−25	127
279	−8	79	−10	87	−20	110	−25	120
280	0	66	−21	114	−26	126	−27	127
281	−1	71	−18	110	−25	124	−19	114
282	0	62	−14	98	−17	105	−23	117
283	−2	60	−22	110	−27	121	−25	118
284	−2	59	−21	106	−27	117	−26	117
285	−5	75	−18	103	−17	102	−24	113
286	−3	62	−21	107	−26	117	−28	118
287	−4	58	−23	108	−27	116	−31	120
288	−9	66	−26	112	−33	122	−37	124
289	−1	79	−10	96	−10	95	−10	94
290	0	71	−12	95	−14	100	−15	102
291	3	68	−5	91	−8	95	−10	99
292	10	44	−9	93	−17	111	−13	106
293	−7	62	−22	94	−28	114	−50	127
294	15	36	−5	86	−6	89	−5	92
295	14	40	9	67	−2	80	17	57
296	16	27	−4	80	−4	82	−5	86
297	12	29	−10	85	−9	85	−13	94
298	1	44	−1	70	−8	81	−12	91
299	20	36	7	60	−1	72	−2	77
300	18	32	9	58	5	64	0	71
301	5	42	5	61	1	67	−1	73
302	1	48	12	50	9	56	4	64
303	10	62	15	50	0	69	−7	81
304	17	46	18	49	1	69	5	64
305	9	64	17	54	7	69	15	57
306	−12	104	10	41	−7	69	1	67
307	−11	97	7	46	−6	67	0	68
308	−16	96	−1	51	−16	77	−10	67
309	−7	88	7	49	−2	64	1	68
310	−8	85	8	52	2	61	0	77
311	−7	85	9	41	−6	67	2	64
312	−9	85	6	47	−3	64	0	68
313	−13	88	2	55	2	57	−5	78
314	4	66	13	41	−3	65	7	55
315	−3	77	10	44	−3	66	5	59
316	−3	76	6	50	0	62	2	65
317	−6	76	5	53	9	51	14	54
318	10	58	13	49	−1	66	15	44
319	−1	76	4	63	−2	71	5	60
320	−1	83	6	64	−2	75	2	70
321	−7	99	−2	69	−1	70	−2	76
322	−14	95	−2	59	−9	72	−18	86
323	2	95	6	70	14	60	12	70
324	0	76	10	44	16	37	5	64
325	−5	74	9	31	0	47	−12	70
326	0	70	12	43	18	35	11	55
327	−11	75	3	53	11	37	5	56
328	1	68	14	34	12	41	0	69
329	0	65	10	38	10	41	2	65
330	−14	73	−3	52	2	48	−6	74
331	3	62	13	40	12	41	5	54
332	4	62	17	32	13	41	7	54
333	−1	68	7	44	0	59	−6	76
334	−13	75	7	38	3	50	−11	82
335	11	55	13	50	19	40	−2	77
336	5	64	10	57	3	66	−2	77
337	12	70	26	43	18	50	25	42

last_significant_coeff_flag, field coded

ctxIdx 338 to 398 (Table 9-23).

ctxIdx	I and SI		cabac_init_idc 0		1		2
ctxIdx	m	n	m	n	m	n	m	n
338	15	6	14	11	19	−6	17	−13
339	6	19	11	14	18	−6	16	−9
340	7	16	9	11	14	0	17	−12
341	12	14	18	11	26	−12	27	−21
342	18	13	21	9	31	−16	37	−30
343	13	11	23	−2	33	−25	41	−40
344	13	15	32	−15	33	−22	42	−41
345	15	16	32	−15	37	−28	48	−47
346	12	23	34	−21	39	−30	39	−32
347	13	23	39	−23	42	−30	46	−40
348	15	20	42	−33	47	−42	52	−51
349	14	26	41	−31	45	−36	46	−41
350	14	44	46	−28	49	−34	52	−39
351	17	40	38	−12	41	−17	43	−19
352	17	47	21	29	32	9	32	11
353	24	17	45	−24	69	−71	61	−55
354	21	21	53	−45	63	−63	56	−46
355	25	22	48	−26	66	−64	62	−50
356	31	27	65	−43	77	−74	81	−67
357	22	29	43	−19	54	−39	45	−20
358	19	35	39	−10	52	−35	35	−2
359	14	50	30	9	41	−10	28	15
360	10	57	18	26	36	0	34	1
361	7	63	20	27	40	−1	39	1
362	−2	77	0	57	30	14	30	17
363	−4	82	−14	82	28	26	20	38
364	−3	94	−5	75	23	37	18	45
365	9	69	−19	97	12	55	15	54
366	−12	109	−35	125	11	65	0	79
367	36	−35	27	0	37	−33	36	−16
368	36	−34	28	0	39	−36	37	−14
369	32	−26	31	−4	40	−37	37	−17
370	37	−30	27	6	38	−30	32	1
371	44	−32	34	8	46	−33	34	15
372	34	−18	30	10	42	−30	29	15
373	34	−15	24	22	40	−24	24	25
374	40	−15	33	19	49	−29	34	22
375	33	−7	22	32	38	−12	31	16
376	35	−5	26	31	40	−10	35	18
377	33	0	21	41	38	−3	31	28
378	38	2	26	44	46	−5	33	41
379	33	13	23	47	31	20	36	28
380	23	35	16	65	29	30	27	47
381	13	58	14	71	25	44	21	62
382	29	−3	8	60	12	48	18	31
383	26	0	6	63	11	49	19	26
384	22	30	17	65	26	45	36	24
385	31	−7	21	24	22	22	24	23
386	35	−15	23	20	23	22	27	16
387	34	−3	26	23	27	21	24	30
388	34	3	27	32	33	20	31	29
389	36	−1	28	23	26	28	22	41
390	34	5	28	24	30	24	22	42
391	32	11	23	40	27	34	16	60
392	35	5	24	32	18	42	15	52
393	34	12	28	29	25	39	14	60
394	39	11	23	42	18	50	3	78
395	30	29	19	57	12	70	−16	123
396	34	26	22	53	21	54	21	53
397	29	39	22	61	14	71	22	56
398	19	66	11	86	11	83	25	61

8 × 8 luma blocks

ctxIdx 402 to 459, for luma blocks with ctxBlockCat 5 (Table 9-24): 402 to 416 significant_coeff_flag frame coded, 417 to 425 last_significant_coeff_flag frame coded, 426 to 435 coeff_abs_level_minus1, 436 to 450 significant_coeff_flag field coded, 451 to 459 last_significant_coeff_flag field coded. SI slices have no 8 × 8 transform, so the first column is for I slices only.

ctxIdx	I		cabac_init_idc 0		1		2
ctxIdx	m	n	m	n	m	n	m	n
402	−17	120	−4	79	−5	85	−3	78
403	−20	112	−7	71	−6	81	−8	74
404	−18	114	−5	69	−10	77	−9	72
405	−11	85	−9	70	−7	81	−10	72
406	−15	92	−8	66	−17	80	−18	75
407	−14	89	−10	68	−18	73	−12	71
408	−26	71	−19	73	−4	74	−11	63
409	−15	81	−12	69	−10	83	−5	70
410	−14	80	−16	70	−9	71	−17	75
411	0	68	−15	67	−9	67	−14	72
412	−14	70	−20	62	−1	61	−16	67
413	−24	56	−19	70	−8	66	−8	53
414	−23	68	−16	66	−14	66	−14	59
415	−24	50	−22	65	0	59	−9	52
416	−11	74	−20	63	2	59	−11	68
417	23	−13	9	−2	17	−10	9	−2
418	26	−13	26	−9	32	−13	30	−10
419	40	−15	33	−9	42	−9	31	−4
420	49	−14	39	−7	49	−5	33	−1
421	44	3	41	−2	53	0	33	7
422	45	6	45	3	64	3	31	12
423	44	34	49	9	68	10	37	23
424	33	54	45	27	66	27	31	38
425	19	82	36	59	47	57	20	64
426	−3	75	−6	66	−5	71	−9	71
427	−1	23	−7	35	0	24	−7	37
428	1	34	−7	42	−1	36	−8	44
429	1	43	−8	45	−2	42	−11	49
430	0	54	−5	48	−2	52	−10	56
431	−2	55	−12	56	−9	57	−12	59
432	0	61	−6	60	−6	63	−8	63
433	1	64	−5	62	−4	65	−9	67
434	0	68	−8	66	−4	67	−6	68
435	−9	92	−8	76	−7	82	−10	79
436	−14	106	−5	85	−3	81	−3	78
437	−13	97	−6	81	−3	76	−8	74
438	−15	90	−10	77	−7	72	−9	72
439	−12	90	−7	81	−6	78	−10	72
440	−18	88	−17	80	−12	72	−18	75
441	−10	73	−18	73	−14	68	−12	71
442	−9	79	−4	74	−3	70	−11	63
443	−14	86	−10	83	−6	76	−5	70
444	−10	73	−9	71	−5	66	−17	75
445	−10	70	−9	67	−5	62	−14	72
446	−10	69	−1	61	0	57	−16	67
447	−5	66	−8	66	−4	61	−8	53
448	−9	64	−14	66	−9	60	−14	59
449	−5	58	0	59	1	54	−9	52
450	2	59	2	59	2	58	−11	68
451	21	−10	21	−13	17	−10	9	−2
452	24	−11	33	−14	32	−13	30	−10
453	28	−8	39	−7	42	−9	31	−4
454	28	−1	46	−2	49	−5	33	−1
455	29	3	51	2	53	0	33	7
456	29	9	60	6	64	3	31	12
457	35	20	61	17	68	10	37	23
458	29	36	55	34	66	27	31	38
459	14	67	42	62	47	57	20	64

.H264 File Format – CABAC initial values