diff options
| author | Vadim Yanitskiy <vyanitskiy@sysmocom.de> | 2023-07-25 03:23:08 +0700 |
|---|---|---|
| committer | Vadim Yanitskiy <vyanitskiy@sysmocom.de> | 2023-07-25 04:23:12 +0700 |
| commit | f93ef0c634a78b4d783a3807683f9d714f48f543 (patch) | |
| tree | f77820c3c5f8fb429b9c3db80317f1d37f1220fb /src/gsm/gsm0808_utils.c | |
| parent | 547a65aae20f5e152084e7a05f9d2ec1c692ec1c (diff) | |
gsm_08_08: define GSM0808_SCT_EXT (separately)
As per 3GPP TS 48.008, section 3.2.2.103, the "Codec Type" field may
contain either a certain 3GPP Speech Codec Type directly (4 bit value),
or the so called "Codec Extension" = 0xFh, in which case the real Codec
Type follows in the next octet as "Extended Codec Type".
CSD is such an example, the encoding is defined as follows:
8 7 6 5 4 3 2 1
+----+----+----+----+-------------------+
| -- | PI | PT | -- | 0xFh |
+----+----+----+----+-------------------+
| Extended Codec Type (CSData) |
+----+----+-----------------------------+
| R2 | R3 | |
+----+----+-----------------------------+
CSData is coded with 0xFDh or '1111 1101' (0xfd).
Let's have the "Codec Extension" value clearly defined in the header
file, but intentionally separate from the other GSM0808_SCT_* values.
Change-Id: Iafaa25070684d2ba400c75fa33e803651a5ce857
Related: OS#6110, OS#4393, OS#4394
Diffstat (limited to 'src/gsm/gsm0808_utils.c')
| -rw-r--r-- | src/gsm/gsm0808_utils.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/src/gsm/gsm0808_utils.c b/src/gsm/gsm0808_utils.c index b8e1ff0f..778630d6 100644 --- a/src/gsm/gsm0808_utils.c +++ b/src/gsm/gsm0808_utils.c @@ -255,7 +255,7 @@ static int enc_speech_codec(struct msgb *msg, header |= (1 << 4); if (type_extended) { - header |= 0x0f; + header |= GSM0808_SCT_EXT; msgb_put_u8(msg, header); msgb_put_u8(msg, sc->type); } else { @@ -347,7 +347,7 @@ int gsm0808_dec_speech_codec(struct gsm0808_speech_codec *sc, /* An extended codec type needs at least two fields, * bail if the input data length is not sufficient. */ - if ((header & 0x0F) == 0x0F && len < 2) + if ((header & 0x0F) == GSM0808_SCT_EXT && len < 2) return -EINVAL; elem++; @@ -362,7 +362,7 @@ int gsm0808_dec_speech_codec(struct gsm0808_speech_codec *sc, if (header & (1 << 4)) sc->tf = true; - if ((header & 0x0F) != 0x0F) { + if ((header & 0x0F) != GSM0808_SCT_EXT) { sc->type = (header & 0x0F); } else { sc->type = *elem; |