diff options
Diffstat (limited to 'src/fmt_rtp_amr.c')
| -rw-r--r-- | src/fmt_rtp_amr.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/src/fmt_rtp_amr.c b/src/fmt_rtp_amr.c index a6a3c9f..4982c83 100644 --- a/src/fmt_rtp_amr.c +++ b/src/fmt_rtp_amr.c @@ -27,6 +27,9 @@ #include <osmocom/gapk/formats.h> #include <osmocom/gapk/utils.h> +/* AMR SID frame is according to TS 126 101 4.2.3 */ +static const uint8_t SILENCE[] = {0x80, 0x44, 0x00, 0x00, 0x00, 0x00, 0x00}; + /* conversion function: RTP payload -> canonical format */ static int rtp_amr_from_canon(uint8_t *dst, const uint8_t *src, unsigned int src_len) @@ -42,6 +45,12 @@ rtp_amr_from_canon(uint8_t *dst, const uint8_t *src, unsigned int src_len) static int rtp_amr_to_canon(uint8_t *dst, const uint8_t *src, unsigned int src_len) { + /* Detect severely damaged frames according to RFC4867 4.3.2 */ + if ((src[1] & 0x04) == 0) { + src = SILENCE; + src_len = sizeof(SILENCE); + } + /* skip Payload Header according to RFC4867 4.4.1 */ memcpy(dst, src+1, src_len-1); |