diff options
| author | Philipp Maier <pmaier@sysmocom.de> | 2017-06-02 13:49:16 +0200 |
|---|---|---|
| committer | Harald Welte <laforge@gnumonks.org> | 2017-06-22 17:08:16 +0000 |
| commit | 884ba0f2bcaf385cabee0b4228a2598d61fa406b (patch) | |
| tree | 34112fe51252784fb170e985ec9ff4f9e9f9039c /src | |
| parent | 3149b0d076477303a38df735fe579b1b06ee17b2 (diff) | |
gsm0808: add function gsm0808_speech_codec_from_chan_type()
The contents of the speech codec element (struct gsm0808_speech_codec),
that is also used in the speech codec list element (struct
gsm0808_speech_codec_list) can be generated directly from the
permitted speech parameter in the channel type field (struct
gsm0808_channel_type) when full AoIP with compressed speech via
RTP/UDP/IP is assumed and when the codec configuration on the air
interface exactly matches the codec configuration on the IP backhaul.
This patch adds a function that can be used as a helper to fill
out spech codec fields by only giving a permitted speech parameter
as input.
Change-Id: I257c972e9fdf0dfe940a8d483447085bd62e50a2
Diffstat (limited to 'src')
| -rw-r--r-- | src/gsm/gsm0808_utils.c | 54 | ||||
| -rw-r--r-- | src/gsm/libosmogsm.map | 1 |
2 files changed, 55 insertions, 0 deletions
diff --git a/src/gsm/gsm0808_utils.c b/src/gsm/gsm0808_utils.c index 64ffec4e..00da04b0 100644 --- a/src/gsm/gsm0808_utils.c +++ b/src/gsm/gsm0808_utils.c @@ -682,4 +682,58 @@ int gsm0808_chan_type_to_speech_codec(uint8_t perm_spch) return -EINVAL; } +/*! \brief Extrapolate a speech codec field from a given permitted speech + * parameter (channel type). + * \param[out] sc Caller provided memory to store the resulting speech codec + * \param[in] perm_spch value that is used to derive the speech codec info + * (see also: enum gsm0808_speech_codec_type in gsm0808_utils.h) + * \returns zero when successful; negative on error */ +int gsm0808_speech_codec_from_chan_type(struct gsm0808_speech_codec *sc, + uint8_t perm_spch) +{ + int rc; + + memset(sc, 0, sizeof(*sc)); + + /* Determine codec type */ + rc = gsm0808_chan_type_to_speech_codec(perm_spch); + if (rc < 0) + return -EINVAL; + sc->type = (uint8_t) rc; + + /* Depending on the speech codec type, pick a default codec + * configuration that exactly matches the configuration on the + * air interface. */ + switch (sc->type) { + case GSM0808_SCT_FR3: + sc->cfg = GSM0808_SC_CFG_DEFAULT_FR_AMR; + break; + case GSM0808_SCT_FR4: + sc->cfg = GSM0808_SC_CFG_DEFAULT_OFR_AMR_WB; + break; + case GSM0808_SCT_FR5: + sc->cfg = GSM0808_SC_CFG_DEFAULT_FR_AMR_WB; + break; + case GSM0808_SCT_HR3: + sc->cfg = GSM0808_SC_CFG_DEFAULT_HR_AMR; + break; + case GSM0808_SCT_HR4: + sc->cfg = GSM0808_SC_CFG_DEFAULT_OHR_AMR_WB; + break; + case GSM0808_SCT_HR6: + sc->cfg = GSM0808_SC_CFG_DEFAULT_OHR_AMR; + break; + default: + /* Note: Not all codec types specify a default setting, + * in this case, we just set the field to zero. */ + sc->cfg = 0; + } + + /* Tag all codecs as "Full IP" + * (see als 3GPP TS 48.008 3.2.2.103) */ + sc->fi = true; + + return 0; +} + /*! @} */ diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map index ccc5b9a4..36cba391 100644 --- a/src/gsm/libosmogsm.map +++ b/src/gsm/libosmogsm.map @@ -163,6 +163,7 @@ gsm0808_dec_encrypt_info; gsm0808_enc_cell_id_list; gsm0808_dec_cell_id_list; gsm0808_convert_to_speech_codec_type; +gsm0808_extrapolate_speech_codec; gsm0858_rsl_ul_meas_enc; |