7 Detailed bit allocation of the Extended AMR-WB codec

26.2903GPPAudio codec processing functionsExtended Adaptive Multi-Rate - Wideband (AMR-WB+) codecRelease 17Transcoding functionsTS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

The detailed allocation of the bits in the AMR-WB+ audio encoder is shown for each frame type in tables 14-17 for mono and tables 18-20 for stereo. These tables show the order of the bits produced by the audio encoder. Note that the most significant bit (MSB) of each codec parameter is always sent first. For TCX512 frames, the frame is split in two equal packets. For TCX1024 frames, the frame is split in four equal packets. The splitting of TCX512 and TCX1024 frames in several packets is explained in Section 5.6.1.

Table 14: Source encoder output parameters in order of occurrence and bit allocation within the audio frame of ACELP coding type

	Bits (MSB‑LSB)
Description	480 bits/frame	416 bits/frame	384 bits/frame	336 bits/frame	304 bits/frame	272 bits/frame	240 bits/frame	208 bits/frame
Mode bits	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1
1^st ISP subvec	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9
2^nd ISP subvec	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17
3^rd ISP subvec	b18 ‑ b23	b18 ‑ b23	b18 ‑ b23	b18 ‑ b23	b18 ‑ b23	b18 ‑ b23	b18 ‑ b23	b18 ‑ b23
4^th ISP subvecr	b24 – b30	b24 – b30	b24 – b30	b24 – b30	b24 – b30	b24 – b30	b24 – b30	b24 – b30
5^th ISP subvec	b31 – b37	b31 – b37	b31 – b37	b31 – b37	b31 – b37	b31 – b37	b31 – b37	b31 – b37
6^th ISP subvec	b38 – b42	b38 – b42	b38 – b42	b38 – b42	b38 – b42	b38 – b42	b38 – b42	b38 – b42
7^th ISP subvec	b43 – b47	b43 – b47	b43 – b47	b43 – b47	b43 – b47	b43 – b47	b43 – b47	b43 – b47
index of mean energy	b48 – b49	b48 – b49	b48 – b49	b48 – b49	b48 – b49	b48 – b49	b48 – b49	b48 – b49
subframe 1
Adaptive CB index	b50 – b58	b50 – b58	b50 – b58	b50 – b58	b50 – b58	b50 – b58	b50 – b58	b50 – b58
LTP-filtering-flag	b59	b59	b59	b59	b59	b59	b59	b59
Algebraic CB indices	b60 – b147	b60 – b131	b60 – b123	b60 – b111	b60 – b103	b60 – b95	b60 – b87	b60 – b79
codebook gains	b148 – b154	b132 – b138	b124 – b130	b112 – b118	b104 – b110	b96 – b102	b88 – b94	b80 – b86
subframe 2
Adaptive CB index	b155 – b160	b139 – b144	b131 – b136	b119 – b124	b111 – b116	b103 – b108	b95 – b100	b87 – b92
LTP-filtering-flag	b161	b145	b137	b125	b117	b109	b101	b93
Algebraic CB indices	b162 – b249	b146 – b217	b138 – b201	b126 – b177	b118 – b161	b110 – b145	b102 – b129	b94 – b113
codebook gains	b250 – b256	b218 – b224	b202 – b208	b178 – b184	b162 – b168	b146 – b152	b130 – b136	b114 – b120
subframe 3
Adaptive CB index	b257 – b265	b225– b233	b209 – b217	b185 – b193	b169 – b177	b153 – b161	b137 – b145	b121 – b129
LTP-filtering-flag	b266	b234	b218	b194	b178	b162	b146	b130
Algebraic CB indices	b267 – b354	b235 – b306	b219 – b282	b195 – b246	b179 – b222	b163 – b198	b147 – b174	b131 – b150
codebook gains	b355 – b361	b307 – b313	b283 – b289	b247 – b253	b223 – b229	b199 – b205	b175 – b181	b151 – b157
subframe 4
Adaptive CB index	b362 – b367	b314 – b319	b290 – b295	b254 – b259	b230 – b235	b206 – b211	b182 – b187	b158 – b163
LTP-filtering-flag	b368	b320	b296	b260	b236	b212	b188	b164
Algebraic CB indices	b369 – b456	b321 – b392	b297 – b360	b261 – b312	b237 – b280	b213 – b248	b189 – b216	b165 – b184
codebook gains	b457 – b463	b493 – b399	b361 – b367	b313 – b319	b281 – b287	b249 – b255	b217 – b223	b185 – b191
Bandwidth extension
Index of HF ISP	b464 – b472	b400 – b408	b368 – b376	b320 – b328	b288 – b296	b256 – b264	b224 – b232	b192 – b200
Index of HF gain	b473 – b479	b409 – b415	b377 – b383	b329– b335	b297 – b303	b265 – b271	b233 – b239	b201 – b207

Table 15: Source encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX256 frame type

	Bits (MSB‑LSB)
Description	480 bits/frame	416 bits/frame	384 bits/frame	336 bits/frame	304 bits/frame	272 bits/frame	240 bits/frame	208 bits/frame
mode bits	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1
1^st ISP subvec	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9
2^nd ISP subvec	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17
3^rd ISP subvec	b18 ‑ b23	b18 ‑ b23	b18 ‑ b23	b18 ‑ b23	b18 ‑ b23	b18 ‑ b23	b18 ‑ b23	b18 ‑ b23
4^th ISP subvecr	b24 – b30	b24 – b30	b24 – b30	b24 – b30	b24 – b30	b24 – b30	b24 – b30	b24 – b30
5^th ISP subvec	b31 – b37	b31 – b37	b31 – b37	b31 – b37	b31 – b37	b31 – b37	b31 – b37	b31 – b37
6^th ISP subvec	b38 – b42	b38 – b42	b38 – b42	b38 – b42	b38 – b42	b38 – b42	b38 – b42	b38 – b42
7^th ISP subvec	b43 – b47	b43 – b47	b43 – b47	b43 – b47	b43 – b47	b43 – b47	b43 – b47	b43 – b47
Noise factor	b48-b50	b48-b50	b48-b50	b48-b50	b48-b50	b48-b50	b48-b50	b48-b50
Global gain	b51 – b57	b51 – b57	b51 – b57	b51 – b57	b51 – b57	b51 – b57	b51 – b57	b51 – b57
Algebraic VQ	b58 – b463	b58 – b399	b58 – b367	b58 – b319	b58 – b287	b58 – b255	b58 – b223	b58 – b191
Bandwidth extension
Index of HF ISP	b464 – b472	b400 – b408	b368 – b376	b320 – b328	b288 – b296	b256 – b264	b224 – b232	b192 – b200
Index of HF gain	b473 – b479	b409 – b415	b377 – b383	b329– b335	b297 – b303	b265 – b271	b233 – b239	b201 – b207

Table 16a: Source encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX512 frame type – First Packet

	Bits (MSB‑LSB)
Description		480 bits/frame	416 bits/frame	384 bits/frame	336 bits/frame	304 bits/frame	272 bits/frame	240 bits/frame	208 bits/frame
mode bits		b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1
1^st ISP subvec		b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9
2^nd ISP subvec		b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17
Noise factor		b18-b20	b18-b20	b18-b20	b18-b20	b18-b20	b18-b20	b18-b20	b18-b20
Global gain		b21 – b27	b21 – b27	b21 – b27	b21 – b27	b21 – b27	b21 – b27	b21 – b27	b21 – b27
Split Algebraic VQ		b28 – b463	b28 – b399	b28 – b367	b28 – b319	b28 – b287	b28 – b255	b28 – b223	b28 – b191
Bandwidth extension
Index of HF ISP		b464 – b472	b400 – b408	b368 – b376	b320 – b328	b288 – b296	b256 – b264	b224 – b232	b192 – b200
Index of HF gain		b473– b479	b409 – b415	b377 – b383	b329– b335	b297 – b303	b265 – b271	b233 – b239	b201 – b207

Table 16b: Source encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX512 frame type – Second Packet

	Bits (MSB‑LSB)
Description	480 bits/frame	416 bits/frame	384 bits/frame	336 bits/frame	304 bits/frame	272 bits/frame	240 bits/frame	208 bits/frame
mode bits	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1
3^rd ISP subvec	b2 – b7	b2 – b7	b2 – b7	b2 – b7	b2 – b7	b2 – b7	b2 – b7	b2 – b7
4^th ISP subvecr	b8 – b14	b8 – b14	b8 – b14	b8 – b14	b8 – b14	b8 – b14	b8 – b14	b8 – b14
5^th ISP subvec	b15 – b21	b15 – b21	b15 – b21	b15 – b21	b15 – b21	b15 – b21	b15 – b21	b15 – b21
6^th ISP subvec	b22 – b26	b22 – b26	b22 – b26	b22 – b26	b22 – b26	b22 – b26	b22 – b26	b22 – b26
7^th ISP subvec	b27 – b31	b27 – b31	b27 – b31	b27 – b31	b27 – b31	b27 – b31	b27 – b31	b27 – b31
Gain redundancy (6 MSBs)	b32-b37	b32-b37	b32-b37	b32-b37	b32-b37	b32-b37	b32-b37	b32-b37
Split Algebraic VQ	b38 – b463	b38 – b399	b38 – b367	b38 – b319	b38 – b287	b38 – b255	b38 – b223	b38 – b191
Bandwidth extension
Gain correction 8×2 bits	b464-b479	b400-b415	b368-b383	b320-b335	b288-b303	b256-b271	b224-b239	b192-b207

Table 17a: Source encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX1024 frame type – First Packet

	Bits (MSB‑LSB)
Description	480 bits/frame	416 bits/frame	384 bits/frame	336 bits/frame	304 bits/frame	272 bits/frame	240 bits/frame	208 bits/frame
mode bits	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1
1^st ISP subvec	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9	b2 – b9
2^nd ISP subvec	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17	b10 – b17
Global gain	b18 – b24	b18 – b24	b18 – b24	b18 – b24	b18 – b24	b18 – b24	b18 – b24	b18 – b24
Split Algebraic VQ	b25 – b463	b25 – b399	b25 – b367	b25 – b319	b25 – b287	b25 – b255	b25 – b223	b25 – b191
Bandwidth extension
Index of HF ISP	b464 – b472	b400 – b408	b368 – b376	b320 – b328	b288 – b296	b256 – b264	b224 – b232	b192 – b200
Index of HF gain	b473 – b479	b409 – b415	b377 – b383	b329– b335	b297 – b303	b265 – b271	b233 – b239	b201 – b207

Table 17b: Source encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX1024 frame type – Second packet

	Bits (MSB‑LSB)
Description	480 bits/frame	416 bits/frame	384 bits/frame	336 bits/frame	304 bits/frame	272 bits/frame	240 bits/frame	208 bits/frame
mode bits	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1
3^rd ISP subvec	b2 – b7	b2 – b7	b2 – b7	b2 – b7	b2 – b7	b2 – b7	b2 – b7	b2 – b7
Noise factor	b8-b10	b8-b10	b8-b10	b8-b10	b8-b10	b8-b10	b8-b10	b8-b10
Global gain parity	b11 – b13	b11 – b13	b11 – b13	b11 – b13	b11 – b13	b11 – b13	b11 – b13	b11 – b13
Split Algebraic VQ	b14– b463	b14 – b399	b14 – b367	b14 – b319	b14 – b287	b14 – b255	b14 – b223	b14 – b191
Bandwidth extension
Gain correction 8×2 bits (MSBs 1^st 8 subframes)	b464-b479	b400-b415	b368-b383	b320-b335	b288-b303	b256-b271	b224-b239	b192-b207

Table 17c: Source encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX1024 frame type – Third packet

	Bits (MSB‑LSB)
Description	480 bits/frame	416 bits/frame	384 bits/frame	336 bits/frame	304 bits/frame	272 bits/frame	240 bits/frame	208 bits/frame
mode bits	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1
4^th ISP subvecr	b2 – b8	b2 – b8	b2 – b8	b2 – b8	b2 – b8	b2 – b8	b2 – b8	b2 – b8
6^th ISP subvec	b9 – b13	b9 – b13	b9 – b13	b9 – b13	b9 – b13	b9 – b13	b9 – b13	b9 – b13
Global gain redundancy	b14 – b16	b14 – b16	b14 – b16	b14 – b16	b14 – b16	b14 – b16	b14 – b16	b14 – b16
Split Algebraic VQ	b17– b463	b17– b399	b17 – b367	b17 – b319	b17 – b287	b17 – b255	b17 – b223	b17 – b191
Bandwidth extension
Gain correction 8×2 bits (MSBs 2^nd 8 subframes)	b464-b479	b400-b415	b368-b383	b320-b335	b288-b303	b256-b271	b224-b239	b192-b207

Table 17d: Source encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX1024 frame type – Fourth packet

	Bits (MSB‑LSB)
Description	480 bits/frame	416 bits/frame	384 bits/frame	336 bits/frame	304 bits/frame	272 bits/frame	240 bits/frame	208 bits/frame
mode bits	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1	b0-b1
5^th ISP subvec	b2 – b8	b2 – b8	b2 – b8	b2 – b8	b2 – b8	b2 – b8	b2 – b8	b2 – b8
7^th ISP subvec	b9 – b13	b9 – b13	b9 – b13	b9 – b13	b9 – b13	b9 – b13	b9 – b13	b9 – b13
Global gain redundancy	b14 – b16	b14 – b16	b14 – b16	b14 – b16	b14 – b16	b14 – b16	b14 – b16	b14 – b16
Split Algebraic VQ	b17– b463	b17– b399	b17 – b367	b17 – b319	b17 – b287	b17 – b255	b17 – b223	b17 – b191
Bandwidth extension
Gain correction 16×1 bits (LSB 16 subframes)	b464-b479	b400-b415	b368-b383	b320-b335	b288-b303	b256-b271	b224-b239	b192-b207

N₁ is the number of bits per frame allocated for the low and midband and is calculated according to

N₁ = N-1, 1 bit unused

Table 18: Stereo encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX48 frame type, mode 0 and 1

	Bits (MSB‑LSB)
Description		N bits/frame <=76	N bits/frame > 76
Midband stereo
Midband filter		b0-b3	b0-b6
Midband gain		b4-b5	b7-b11
Lowband stereo
Mode bits		b6-b7	b12-b13
reserved		b8	b14
Balance factor		B9-b15	b15-b21
Global gain		b16 – b22	b22-b28
Algebraic VQ		b23 – bN₁	b29- bN₁

Table 19a: Stereo encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX96 frame type, mode 2 – First packet

	Bits (MSB‑LSB)
Description		N bits/frame <=76	N bits/frame > 76
Midband stereo
Midband filter		b0-b3	b0-b6
Midband gain		b4-b5	b7-b11
Lowband stereo
Mode bits		b6-b7	b12-b13
reserved		b8	b14
Balance factor		B9-b15	b15-b21
Algebraic VQ		b16 – bN₁	b22- bN₁

Table 19b: Stereo encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX96 frame type, mode 2 – Second packet

	Bits (MSB‑LSB)
Description		N bits/frame <=76	N bits/frame > 76
Midband stereo
Midband filter		b0-b3	b0-b6
Midband gain		b4-b5	b7-b11
Lowband stereo
Mode bits		b6-b7	b12-b13
reserved		b8	b14
Global gain		b9-b15	b15-b21
Algebraic VQ		b16– bN₁	b22- bN₁

Table 20a: Stereo encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX96 frame type, mode 3 – First packet

	Bits (MSB‑LSB)
Description		N bits/frame <=76	N bits/frame > 76
Midband stereo
Midband filter		b0-b3	b0-b6
Midband gain		b4-b5	b7-b11
Lowband stereo
Mode bits		b6-b7	b12-b13
reserved		b8	b14
Balance factor		b9-b15	b15-b21
Algebraic VQ		b16– bN₁	b22- bN₁

Table 20b: Stereo encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX96 frame type, mode 3 – Second packet

	Bits (MSB‑LSB)
Description		N bits/frame <=76	N bits/frame > 76
Midband stereo
Midband filter		b0-b3	b0-b6
Midband gain		b4-b5	b7-b11
Lowband stereo
Mode bits		b6-b7	b12-b13
reserved		b8	b14
Algebraic VQ		b9 – bN₁	b15- bN₁

Table 20c: Stereo encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX96 frame type, mode 3 – Third packet

	Bits (MSB‑LSB)
Description		N bits/frame <=76	N bits/frame > 76
Midband stereo
Midband filter		b0-b3	b0-b6
Midband gain		b4-b5	b7-b11
Lowband stereo
Mode bits		b6-b7	b12-b13
reserved		b8	b14
Global gain		B9-b15	b15-b21
Algebraic VQ		b16 – bN₁	b22- bN₁

Table 20d: Stereo encoder output parameters in order of occurrence and bit allocation within the audio frame of TCX96 frame type, mode 3 – Fourth packet

	Bits (MSB‑LSB)
Description		N bits/frame <=76	N bits/frame > 76
Midband stereo
Midband filter		b0-b3	b0-b6
Midband gain		b4-b5	b7-b11
Lowband stereo
Mode bits		b6-b7	b12-b13
reserved		b8	b14
Algebraic VQ		b9 – bN₁	b15- bN₁