diff options
Diffstat (limited to 'src/gsm/gsm0808_utils.c')
| -rw-r--r-- | src/gsm/gsm0808_utils.c | 54 |
1 files changed, 54 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; +} + /*! @} */ |