/* TRAU frame to RTP conversion */ /* (C) 2009,2020 by Harald Welte * All Rights Reserved * * SPDX-License-Identifier: GPL-2.0+ * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . * */ #include #include #include #include #include #include #include /* this corresponds to the bit-lengths of the individual codec * parameters as indicated in Table 1.1 of TS 46.010 */ static const uint8_t gsm_fr_map[] = { 6, 6, 5, 5, 4, 4, 3, 3, 7, 2, 2, 6, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 7, 2, 2, 6, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 7, 2, 2, 6, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 7, 2, 2, 6, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3 }; /* * EFR TRAU parity * * g(x) = x^3 + x^1 + 1 */ static const struct osmo_crc8gen_code gsm0860_efr_crc3 = { .bits = 3, .poly = 0x3, .init = 0x0, .remainder = 0x7, }; /* re-combine EFR parity bits */ static inline void efr_parity_bits_1(ubit_t *check_bits, const ubit_t *d_bits) { memcpy(check_bits + 0 , d_bits + 0, 22); memcpy(check_bits + 22 , d_bits + 24, 3); check_bits[25] = d_bits[28]; } static inline void efr_parity_bits_2(ubit_t *check_bits, const ubit_t *d_bits) { memcpy(check_bits + 0 , d_bits + 42, 10); memcpy(check_bits + 10 , d_bits + 90, 2); } static inline void efr_parity_bits_3(ubit_t *check_bits, const ubit_t *d_bits) { memcpy(check_bits + 0 , d_bits + 98, 5); check_bits[5] = d_bits[104]; memcpy(check_bits + 6 , d_bits + 143, 2); } static inline void efr_parity_bits_4(ubit_t *check_bits, const ubit_t *d_bits) { memcpy(check_bits + 0 , d_bits + 151, 10); memcpy(check_bits + 10 , d_bits + 199, 2); } static inline void efr_parity_bits_5(ubit_t *check_bits, const ubit_t *d_bits) { memcpy(check_bits + 0 , d_bits + 207, 5); check_bits[5] = d_bits[213]; memcpy(check_bits + 6 , d_bits + 252, 2); } //static const uint8_t c_bits_check_fr[] = { 0, 0, 0, 1, 0 }; //static const uint8_t c_bits_check_efr[] = { 1, 1, 0, 1, 0 }; /*! Generate the 33 bytes RTP payload for GSM-FR from a decoded TRAU frame. * \param[out] out caller-provided output buffer * \param[in] out_len length of out buffer in bytes * \param[in] fr input TRAU frame in decoded form * \returns number of bytes generated in 'out'; negative on error. */ static int trau2rtp_fr(uint8_t *out, size_t out_len, const struct osmo_trau_frame *tf) { int i, j, k, l, o; if (tf->type != OSMO_TRAU16_FT_FR) return -EINVAL; /* FR Data Bits according to TS 48.060 Section 5.5.1.1.2 */ if (tf->c_bits[11]) /* BFI */ return 0; if (out_len < GSM_FR_BYTES) return -ENOSPC; out[0] = 0xd << 4; /* reassemble d-bits */ i = 0; /* counts bits */ j = 4; /* counts output bits */ k = gsm_fr_map[0]-1; /* current number bit in element */ l = 0; /* counts element bits */ o = 0; /* offset input bits */ while (i < 260) { out[j/8] |= (tf->d_bits[k+o] << (7-(j%8))); /* to avoid out-of-bounds access in gsm_fr_map[++l] */ if (i == 259) break; if (--k < 0) { o += gsm_fr_map[l]; k = gsm_fr_map[++l]-1; } i++; j++; } return GSM_FR_BYTES; } /* See Section 5.2 of RFC5993 */ enum rtp_hr_ietf_ft { FT_GOOD_SPEECH = 0, FT_GOOD_SID = 2, FT_NO_DATA = 7, }; static const uint8_t rtp_hr_sid[14] = { 0x00, 0x00, 0x00, 0x00, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; /*! Generate the 14 bytes ETSI TS 101 318 RTP payload for HR from a decoded 16k TRAU frame. * Note that thsi differs from the IETF RFC5993 format. However, as OsmoBTS implements * the TS 101 318 format, we also use the same format here. osmo-mgw can convert them. * \param[out] out caller-provided output buffer * \param[in] out_len length of out buffer in bytes * \param[in] tf input TRAU frame in decoded form * \returns number of bytes generated in 'out'; negative on error. */ static int trau2rtp_hr16(uint8_t *out, size_t out_len, const struct osmo_trau_frame *tf) { unsigned int i; if (tf->type != OSMO_TRAU16_FT_HR) return -EINVAL; /* HR Data Bits according to TS 48.061 Section 5.1.4.1.1 */ if (tf->dir == OSMO_TRAU_DIR_UL && tf->c_bits[11]) /* C12: BFI */ goto bad_frame; if (out_len < GSM_HR_BYTES) return -ENOSPC; /* TS 101 318 Section 5.2: The order of occurrence of the codec parameters in the buffer is * the same as order of occurrence over the Abis as defined in annex B of ETS 300 969 * [which is 3GPP TS 46.020 */ osmo_ubit2pbit(out, tf->d_bits, 112); if (tf->c_bits[12] || tf->c_bits[13]) { /* Generate SID frame as per TS 101 318 Section 5.2.2 */ for (i = 0; i < sizeof(rtp_hr_sid); i++) out[i] = out[i] | rtp_hr_sid[i]; } return GSM_HR_BYTES; bad_frame: return 0; } /*! Generate the 31 bytes RTP payload for GSM-EFR from a decoded TRAU frame. * \param[out] out caller-provided output buffer * \param[in] out_len length of out buffer in bytes * \param[in] fr input TRAU frame in decoded form * \returns number of bytes generated in 'out'; negative on error. */ static int trau2rtp_efr(uint8_t *out, size_t out_len, const struct osmo_trau_frame *tf) { int i, j, rc; ubit_t check_bits[26]; if (tf->type != OSMO_TRAU16_FT_EFR) return -EINVAL; /* FR Data Bits according to TS 48.060 Section 5.5.1.1.2 */ if (tf->c_bits[11]) /* BFI */ return 0; if (out_len < GSM_EFR_BYTES) return -ENOSPC; if (tf->c_bits[11]) /* BFI */ goto bad_frame; out[0] = 0xc << 4; /* reassemble d-bits */ for (i = 1, j = 4; i < 39; i++, j++) out[j/8] |= (tf->d_bits[i] << (7-(j%8))); efr_parity_bits_1(check_bits, tf->d_bits); rc = osmo_crc8gen_check_bits(&gsm0860_efr_crc3, check_bits, 26, tf->d_bits + 39); if (rc) goto bad_frame; for (i = 42, j = 42; i < 95; i++, j++) out[j/8] |= (tf->d_bits[i] << (7-(j%8))); efr_parity_bits_2(check_bits, tf->d_bits); rc = osmo_crc8gen_check_bits(&gsm0860_efr_crc3, check_bits, 12, tf->d_bits + 95); if (rc) goto bad_frame; for (i = 98, j = 95; i < 148; i++, j++) out[j/8] |= (tf->d_bits[i] << (7-(j%8))); efr_parity_bits_3(check_bits, tf->d_bits); rc = osmo_crc8gen_check_bits(&gsm0860_efr_crc3, check_bits, 8, tf->d_bits + 148); if (rc) goto bad_frame; for (i = 151, j = 145; i < 204; i++, j++) out[j/8] |= (tf->d_bits[i] << (7-(j%8))); efr_parity_bits_4(check_bits, tf->d_bits); rc = osmo_crc8gen_check_bits(&gsm0860_efr_crc3, check_bits, 12, tf->d_bits + 204); if (rc) goto bad_frame; for (i = 207, j = 198; i < 257; i++, j++) out[j/8] |= (tf->d_bits[i] << (7-(j%8))); efr_parity_bits_5(check_bits, tf->d_bits); rc = osmo_crc8gen_check_bits(&gsm0860_efr_crc3, check_bits, 8, tf->d_bits + 257); if (rc) goto bad_frame; return GSM_EFR_BYTES; bad_frame: return 0; } /* TS 48.060 Section 5.5.1.1.2 */ static int rtp2trau_fr(struct osmo_trau_frame *tf, const uint8_t *data, size_t data_len) { int i, j, k, l, o; /* data_len == 0 for BFI frame */ if (data_len < GSM_FR_BYTES && data_len != 0) return -EINVAL; if (data_len && data[0] >> 4 != 0xd) return -EINVAL; tf->type = OSMO_TRAU16_FT_FR; /* FR Data Bits according to TS 48.060 Section 5.5.1.1.2 */ /* FIXME: Generate SID frames? */ /* set c-bits and t-bits */ if (tf->dir == OSMO_TRAU_DIR_UL) { /* C1 .. C5 */ tf->c_bits[0] = 0; tf->c_bits[1] = 0; tf->c_bits[2] = 0; tf->c_bits[3] = 1; tf->c_bits[4] = 0; } else { /* C1 .. C5 */ tf->c_bits[0] = 1; tf->c_bits[1] = 1; tf->c_bits[2] = 1; tf->c_bits[3] = 0; tf->c_bits[4] = 0; } memset(&tf->c_bits[5], 0, 6); /* C6 .. C11: Time Alignment */ if (tf->dir == OSMO_TRAU_DIR_UL) { if (data_len == 0) tf->c_bits[11] = 1; /* C12: BFI */ else tf->c_bits[11] = 0; /* C12: BFI */ tf->c_bits[12] = 0; /* C13: SID=0 */ tf->c_bits[13] = 0; /* C14: SID=0 */ tf->c_bits[14] = 0; /* C15: TAF (SACCH or not) */ tf->c_bits[15] = 1; /* C16: spare */ tf->c_bits[16] = 0; /* C17: DTXd not applied */ } else { memset(&tf->c_bits[11], 1, 10); /* C12 .. C15: spare */ tf->c_bits[15] = 1; /* C16: SP=1 */ } memset(&tf->c_bits[17], 1, 4); /* C18 .. C12: spare */ memset(&tf->t_bits[0], 1, 4); if (!data_len) return 0; /* reassemble d-bits */ i = 0; /* counts bits */ j = 4; /* counts input bits */ k = gsm_fr_map[0]-1; /* current number bit in element */ l = 0; /* counts element bits */ o = 0; /* offset output bits */ while (i < 260) { tf->d_bits[k+o] = (data[j/8] >> (7-(j%8))) & 1; /* to avoid out-of-bounds access in gsm_fr_map[++l] */ if (i == 259) break; if (--k < 0) { o += gsm_fr_map[l]; k = gsm_fr_map[++l]-1; } i++; j++; } return 0; } /* does the RTP HR payload resemble a SID frame or not */ static bool is_rtp_hr_sid(const uint8_t *data, const uint8_t data_len) { int i; if (data_len < GSM_HR_BYTES) return false; for (i = 0; i < GSM_HR_BYTES; i++) { if ((data[i] & rtp_hr_sid[i]) != rtp_hr_sid[i]) return false; } return true; } static int rtp2trau_hr16(struct osmo_trau_frame *tf, const uint8_t *data, size_t data_len) { if (data_len < GSM_HR_BYTES && data_len != 0) return -EINVAL; tf->type = OSMO_TRAU16_FT_HR; if (tf->dir == OSMO_TRAU_DIR_UL) { /* C1 .. C5 */ tf->c_bits[0] = 0; tf->c_bits[1] = 0; tf->c_bits[2] = 0; tf->c_bits[3] = 1; tf->c_bits[4] = 1; } else { /* C1 .. C5 */ tf->c_bits[0] = 1; tf->c_bits[1] = 1; tf->c_bits[2] = 1; tf->c_bits[3] = 0; tf->c_bits[4] = 1; } /* C6.. C11: Time Alignment */ memset(tf->c_bits + 5, 0, 6); if (tf->dir == OSMO_TRAU_DIR_UL) { /* BFI */ if (data_len == 0) tf->c_bits[11] = 1; else tf->c_bits[11] = 0; if (is_rtp_hr_sid(data, data_len)) { /* SID=2 is a valid SID frame */ tf->c_bits[12] = 1; tf->c_bits[13] = 0; } else { tf->c_bits[12] = 0; tf->c_bits[13] = 0; } /* FIXME: C15: TAF */ tf->c_bits[15] = 0; /* C16: SP */ tf->c_bits[16] = 0; /* C17: DTXd shall not be applied */ } else { tf->c_bits[11] = 0; /* C12: UFE */ tf->c_bits[12] = 1; /* C13: spare */ tf->c_bits[13] = 1; /* C14: spare */ tf->c_bits[14] = 1; /* C15: spare */ if (is_rtp_hr_sid(data, data_len)) tf->c_bits[15] = 0; /* C16: SP */ else tf->c_bits[15] = 1; /* C16: SP */ tf->c_bits[16] = 1; /* C17: spare */ } memset(tf->c_bits+17, 1, 4); /* C18..C21: spare */ memset(&tf->t_bits[0], 1, 4); if (tf->dir == OSMO_TRAU_DIR_UL) tf->ufi = 0; else tf->ufi = 1; /* CRC is computed by TRAU frame encoder */ if (data_len) memcpy(tf->d_bits, data, GSM_HR_BYTES); return 0; } /* TS 48.060 Section 5.5.1.1.2 */ static int rtp2trau_efr(struct osmo_trau_frame *tf, const uint8_t *data, size_t data_len) { int i, j; ubit_t check_bits[26]; /* data_len == 0 for BFI frame */ if (data_len < GSM_EFR_BYTES && data_len != 0) return -EINVAL; if (data_len && data[0] >> 4 != 0xc) return -EINVAL; tf->type = OSMO_TRAU16_FT_EFR; /* FR Data Bits according to TS 48.060 Section 5.5.1.1.2 */ /* set c-bits and t-bits */ tf->c_bits[0] = 1; tf->c_bits[1] = 1; tf->c_bits[2] = 0; tf->c_bits[3] = 1; tf->c_bits[4] = 0; memset(&tf->c_bits[5], 0, 6); /* C6 .. C11: Time Alignment */ if (tf->dir == OSMO_TRAU_DIR_UL) { if (data_len == 0) tf->c_bits[11] = 1; /* C12: BFI=1 */ else tf->c_bits[11] = 0; /* C12: BFI=1 */ /* FIXME: Generate SID frames? */ tf->c_bits[12] = 0; /* C13: SID=0 */ tf->c_bits[13] = 0; /* C14: SID=0 */ tf->c_bits[14] = 0; /* C15: TAF (SACCH) */ tf->c_bits[15] = 1; /* C16: spare */ tf->c_bits[16] = 0; /* C17: DTXd applied */ } else { tf->c_bits[11] = 1; /* C12: UFE (good uplink) */ memset(&tf->c_bits[12], 1, 3); /* C13 .. C15: spare */ tf->c_bits[15] = 1; /* C16: SP=1 */ tf->c_bits[16] = 1; /* C17: spare */ } memset(&tf->c_bits[17], 1, 4); /* C18 .. C21: spare */ memset(&tf->t_bits[0], 1, 4); if (data_len == 0) return 0; /* reassemble d-bits */ tf->d_bits[0] = 1; for (i = 1, j = 4; i < 39; i++, j++) tf->d_bits[i] = (data[j/8] >> (7-(j%8))) & 1; efr_parity_bits_1(check_bits, tf->d_bits); osmo_crc8gen_set_bits(&gsm0860_efr_crc3, check_bits, 26, tf->d_bits + 39); for (i = 42, j = 42; i < 95; i++, j++) tf->d_bits[i] = (data[j/8] >> (7-(j%8))) & 1; efr_parity_bits_2(check_bits, tf->d_bits); osmo_crc8gen_set_bits(&gsm0860_efr_crc3, check_bits, 12, tf->d_bits + 95); for (i = 98, j = 95; i < 148; i++, j++) tf->d_bits[i] = (data[j/8] >> (7-(j%8))) & 1; efr_parity_bits_3(check_bits, tf->d_bits); osmo_crc8gen_set_bits(&gsm0860_efr_crc3, check_bits, 8, tf->d_bits + 148); for (i = 151, j = 145; i < 204; i++, j++) tf->d_bits[i] = (data[j/8] >> (7-(j%8))) & 1; efr_parity_bits_4(check_bits, tf->d_bits); osmo_crc8gen_set_bits(&gsm0860_efr_crc3, check_bits, 12, tf->d_bits + 204); for (i = 207, j = 198; i < 257; i++, j++) tf->d_bits[i] = (data[j/8] >> (7-(j%8))) & 1; efr_parity_bits_5(check_bits, tf->d_bits); osmo_crc8gen_set_bits(&gsm0860_efr_crc3, check_bits, 8, tf->d_bits + 257); return 0; } #if 0 static inline memcpy_inc(uint8_t *out, const uint8_t *in, size_t len, unsigned int *idx) { memcpy_inc(out, in, len); *idx += len; } static int amr_speech_extract_sbits(ubit_t *s_bits, const struct osmo_trau_frame *tf, enum osmo_amr_mode mode) { unsigned int s_idx = 0; switch (mode) { case AMR_4_75: memcpy_inc(s_bits + s_idx, tf->d_bits + 44, 67 - 44, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 67, 92 - 67, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 95, 108 - 95, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 111, 132 - 111, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 135, 148 - 135, &s_idx); break; case AMR_5_15: memcpy_inc(s_bits + s_idx, tf->d_bits + 46, 96 - 46, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 69, 92 - 69, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 95, 114 - 95, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 117, 136 - 117, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 139, 158 - 139, &s_idx); break; case AMR_5_90: memcpy_inc(s_bits + s_idx, tf->d_bits + 41, 67 - 41, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 67, 92 - 67, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 95, 116 - 95, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 119, 144 - 119, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 147, 168 - 147, &s_idx); break; case AMR_6_70: memcpy_inc(s_bits + s_idx, tf->d_bits + 37, 63 - 37, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 63, 92 - 63, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 95, 120 - 95, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 123, 152 - 123, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 155, 180 - 155, &s_idx); break; case AMR_7_40: memcpy_inc(s_bits + s_idx, tf->d_bits + 34, 60 - 34, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 60, 92 - 60, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 95, 124 - 95, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 127, 159 - 127, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 162, 191 - 162, &s_idx); break; case AMR_7_95: memcpy_inc(s_bits + s_idx, tf->d_bits + 31, 58 - 31, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 58, 92 - 58, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 95, 127 - 95, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 130, 164 - 130, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 167, 199 - 167, &s_idx); break; case AMR_10_2: memcpy_inc(s_bits + s_idx, tf->d_bits + 20, 46 - 20, &s_idx); /* D21..D46 */ memcpy_inc(s_bits + s_idx, tf->d_bits + 46, 92 - 46, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 95, 138 - 95, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 141, 187 - 141, &s_idx); memcpy_inc(s_bits + s_idx, tf->d_bits + 190, 233 - 190, &s_idx); break; case AMR_12_2: memcpy_inc(s_bits + s_idx, tf->d_bits + 0, 38 - 0, &s_idx); /* D1..D38 */ memcpy_inc(s_bits + s_idx, tf->d_bits + 38, 91 - 38, &s_idx); /* D39..D91 */ memcpy_inc(s_bits + s_idx, tf->d_bits + 94, 144 - 94, &s_idx); /* D95..D144 */ memcpy_inc(s_bits + s_idx, tf->d_bits + 147, 200 - 147, &s_idx);/* D148..D200 */ memcpy_inc(s_bits + s_idx, tf->d_bits + 203, 253 - 203, &s_idx);/* D204..D253 */ break; } return s_idx; } /* TS 48.060 Section 5.5.1.2.2 */ static int trau2rtp_16(uint8_t *out, const struct osmo_trau_frame *tf, enum osmo_amr_mode last_cmi) { enum osmo_amr_mode mode = last_cmi; uint8_t frame_class = tf->c_bits[21] << 1 | tf->c_bits[20]; uint8_t cmr_cmi = tf->c_bits[23] << 2 | tf->c_bits[24] << 1 | tf->cb_bits[25]; uint8_t no_speech_cls; uint8_t s_bits[242]; uint8_t d_bits[242]; unsigned int s_idx = 0; ubit_t rif = FIXME; if (tf->type != OSMO_TRAU16_FT_AMR) return -EINVAL; if (rif == 0) mode = cmr_cmi; switch (frame_class) { case 0: // no speech no_speech_cls = tf->d_bits[32] << 2 | tf->d_bits[33] << 1 | tf->d_bits[34]; cmi_abs = tf->d_bits[35] << 2 | tf->d_bits[36] < 1 || tf->d_bits[37]; cmr_abs = tf->d_bits[38] << 2 | tf->d_bits[39] < 1 || tf->d_bits[40]; switch (no_speech_cls) { case 7: // sid first break; case 6: // onset break; case 5: // sid_update break; case 4: // sid_bad break; case 0: // no_data break; } break; case 1: // speech bad break; case 2: case 3: /* Extract the s-bits from the TRAU frame */ amr_speech_extract_sbits(s_bits, tf, mode); /* Convert the s-bits to d-bits */ osmo_amr_s_to_d(d_bits, s_bits, mode); break; } } int trau2rtp_amr(uint8_t *out, const struct osmo_trau_frame *tf, enum osmo_amr_mode last_cmi)) { switch (tf->type) { case OSMO_TRAU16_FT_AMR: return trau2rtp_16(out, tf, last_cmi); case OSMO_TRAU8_AMR_LOW: case OSMO_TRAU8_AMR_6k7: case OSMO_TRAU8_AMR_7k4: default: return -EINVAL; } } #endif int osmo_trau2rtp(uint8_t *out, size_t out_len, const struct osmo_trau_frame *tf, struct osmo_trau2rtp_state *st) { switch (tf->type) { case OSMO_TRAU16_FT_FR: return trau2rtp_fr(out, out_len, tf); case OSMO_TRAU16_FT_EFR: return trau2rtp_efr(out, out_len, tf); case OSMO_TRAU16_FT_HR: return trau2rtp_hr16(out, out_len, tf); default: return -EINVAL; } } int osmo_rtp2trau(struct osmo_trau_frame *tf, const uint8_t *rtp, size_t rtp_len, struct osmo_trau2rtp_state *st) { switch (st->type) { case OSMO_TRAU16_FT_FR: return rtp2trau_fr(tf, rtp, rtp_len); case OSMO_TRAU16_FT_EFR: return rtp2trau_efr(tf, rtp, rtp_len); case OSMO_TRAU16_FT_HR: return rtp2trau_hr16(tf, rtp, rtp_len); default: return -EINVAL; } }