diff options
Diffstat (limited to 'src/codec')
| -rw-r--r-- | src/codec/Makefile.am | 2 | ||||
| -rw-r--r-- | src/codec/gsm690.c | 106 |
2 files changed, 107 insertions, 1 deletions
diff --git a/src/codec/Makefile.am b/src/codec/Makefile.am index b4834e52..619897f5 100644 --- a/src/codec/Makefile.am +++ b/src/codec/Makefile.am @@ -2,7 +2,7 @@ # Please read Chapter 6 "Library interface versions" of the libtool documentation before making any modification LIBVERSION=0:0:0 -AM_CPPFLAGS = -I$(top_srcdir)/include +AM_CPPFLAGS = -I$(top_srcdir)/include $(TALLOC_CFLAGS) AM_CFLAGS = -Wall lib_LTLIBRARIES = libosmocodec.la diff --git a/src/codec/gsm690.c b/src/codec/gsm690.c index fdf3302f..0f4bf8fe 100644 --- a/src/codec/gsm690.c +++ b/src/codec/gsm690.c @@ -22,7 +22,12 @@ */ #include <stdint.h> +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <osmocom/core/utils.h> +#include <osmocom/codec/codec.h> /* * These table map between the raw encoder parameter output and * the format used before channel coding. Both in GSM and in various @@ -208,3 +213,104 @@ const uint16_t gsm690_4_75_bitorder[95] = { 88, 90, 91, 34, 55, 68, 89, 37, 58, 71, 92, 31, 52, 65, 86, }; + +static const uint8_t amr_len_by_ft[16] = { + 12, 13, 15, 17, 19, 20, 26, 31, 0, 0, 0, 0, 0, 0, 0, 0 +}; + +const struct value_string osmo_amr_type_names[] = { + { AMR_4_75, "AMR 4,75 kbits/s" }, + { AMR_5_15, "AMR 5,15 kbit/s" }, + { AMR_5_90, "AMR 5,90 kbit/s" }, + { AMR_6_70, "AMR 6,70 kbit/s (PDC-EFR)" }, + { AMR_7_40, "AMR 7,40 kbit/s (TDMA-EFR)" }, + { AMR_7_95, "AMR 7,95 kbit/s" }, + { AMR_10_2, "AMR 10,2 kbit/s" }, + { AMR_12_2, "AMR 12,2 kbit/s (GSM-EFR)" }, + { AMR_SID, "AMR SID" }, + { AMR_GSM_EFR_SID, "GSM-EFR SID" }, + { AMR_TDMA_EFR_SID, "TDMA-EFR SID" }, + { AMR_PDC_EFR_SID, "PDC-EFR SID" }, + { AMR_NO_DATA, "No Data/NA" }, + { 0, NULL }, +}; + +/*! \brief Decode various AMR parameters from RTP payload (RFC 4867) acording to + * 3GPP TS 26.101 + * \param[in] rtppayload Payload from RTP packet + * \param[in] payload_len length of rtppayload + * \param[out] cmr AMR Codec Mode Request, not filled if NULL + * \param[out] cmi AMR Codec Mode Indicator, -1 if not applicable for this type, + * not filled if NULL + * \param[out] ft AMR Frame Type, not filled if NULL + * \param[out] bfi AMR Bad Frame Indicator, not filled if NULL + * \param[out] sti AMR SID Type Indicator, -1 if not applicable for this type, + * not filled if NULL + * \returns length of AMR data or negative value on error + */ +int osmo_amr_rtp_dec(const uint8_t *rtppayload, int payload_len, uint8_t *cmr, + int8_t *cmi, enum osmo_amr_type *ft, + enum osmo_amr_quality *bfi, int8_t *sti) +{ + /* RFC 4867 § 4.4.2 ToC - compound payloads are not supported: F = 0 */ + uint8_t type = (rtppayload[1] >> 3) & 0xf; + + /* compound payloads are not supported */ + if (rtppayload[1] >> 7) + return -ENOTSUP; + + if (payload_len - 2 < amr_len_by_ft[type]) + return -ENOTSUP; + + if (payload_len < 2) + return -EINVAL; + + if (ft) + *ft = type; + + if (cmr) + *cmr = rtppayload[0] >> 4; + + if (bfi) + *bfi = (rtppayload[1] >> 2) & 1; + + /* Table 6 in 3GPP TS 26.101 */ + if (cmi) + *cmi = (type == AMR_SID) ? ((rtppayload[6] >> 1) & 7) : -1; + + if (sti) + *sti = (type == AMR_SID) ? (rtppayload[6] & 0x10) : -1; + + return 2 + amr_len_by_ft[type]; +} + +/*! \brief Encode various AMR parameters from RTP payload (RFC 4867) + * \param[out] payload Payload for RTP packet, contains speech data (if any) + * except for have 2 first bytes where header will be built + * \param[in] cmr AMR codec Mode Request + * \param[in] ft AMR Frame Type + * \param[in] bfi AMR Bad Frame Indicator + * \returns length of AMR data (header + ToC + speech data) or negative value + * on error + * + * Note: only octet-aligned mode is supported so the header occupies 2 full + * bytes. Optional interleaving header is not supported. + */ +int osmo_amr_rtp_enc(uint8_t *payload, uint8_t cmr, enum osmo_amr_type ft, + enum osmo_amr_quality bfi) +{ + if (cmr > 15) + return -EINVAL; + + if (ft > 15) + return -ENOTSUP; + + /* RFC 4867 § 4.3.1 payload header */ + payload[0] = cmr << 4; + + /* RFC 4867 § 4.4.2 ToC - compound payloads are not supported: F = 0 */ + payload[1] = (((uint8_t)ft) << 3) | (((uint8_t)bfi) << 2); + + /* speech data */ + return 2 + amr_len_by_ft[ft]; +} |