AMR codec support

diff --git a/gsm.cpp b/gsm.cpp
index 7502eed..6a7445d 100644 (file)
--- a/gsm.cpp
+++ b/gsm.cpp
@@ -186,6 +186,8 @@ Pgsm::Pgsm(int type, char *portname, struct port_settings *settings, struct inte
        p_g_hr_encoder = NULL;
        p_g_amr_decoder = NULL;
        p_g_amr_encoder = NULL;
+       p_g_amr_cmr = 0;
+       p_g_amr_cmr_valid = 0;
 #ifdef WITH_GSMFR
        p_g_fr_decoder = gsm_fr_create();
        p_g_fr_encoder = gsm_fr_create();
@@ -248,7 +250,7 @@ void Pgsm::frame_receive(void *arg)
 {
        struct gsm_data_frame *frame = (struct gsm_data_frame *)arg;
        unsigned char data[160];
-       int i;
+       int i, cmr;
 
        if (!p_g_fr_decoder)
                return;
@@ -294,6 +296,30 @@ void Pgsm::frame_receive(void *arg)
                }
 #endif
                break;
+       case GSM_TCH_FRAME_AMR:
+               if (p_g_media_type != MEDIA_TYPE_AMR) {
+                       PERROR("AMR frame, but current media type mismatches.\n");
+                       return;
+               }
+               if (!p_g_amr_decoder) {
+                       PERROR("AMR frame, but decoder not created.\n");
+                       return;
+               }
+               cmr = (frame->data[1] >> 4);
+               if (cmr <= 7) {
+                       p_g_amr_cmr = cmr;
+                       p_g_amr_cmr_valid = 1;
+               }
+               if (!(frame->data[2] & 0x04))
+                       goto bfi;
+#ifdef WITH_GSMAMR
+               /* decode (skip length byte in front) */
+               gsm_amr_decode(p_g_amr_decoder, frame->data + 1, p_g_samples);
+               for (i = 0; i < 160; i++) {
+                       data[i] = audio_s16_to_law[p_g_samples[i] & 0xffff];
+               }
+#endif
+               break;
        case GSM_BAD_FRAME:
        default:
 bfi:
@@ -341,6 +367,7 @@ int Pgsm::bridge_rx(unsigned char *data, int len)
 int Pgsm::audio_send(unsigned char *data, int len)
 {
        unsigned char frame[33];
+       int ret;
 
        /* record data */
        if (p_record)
@@ -386,6 +413,22 @@ int Pgsm::audio_send(unsigned char *data, int len)
                        frame_send(frame, 31, GSM_TCHF_FRAME_EFR);
 #endif
                        break;
+               case MEDIA_TYPE_AMR:
+                       if (!p_g_amr_encoder) {
+                               PERROR("AMR frame, but encoder not created.\n");
+                               break;
+                       }
+                       if (!p_g_amr_cmr_valid) {
+                               PDEBUG(DEBUG_GSM, "no valid CMR yet.\n");
+                               break;
+                       }
+#ifdef WITH_GSMAMR
+                       /* encode data (prefix a length byte) */
+                       ret = gsm_amr_encode(p_g_amr_encoder, p_g_rxdata, frame + 1, p_g_amr_cmr);
+                       frame[0] = ret;
+                       frame_send(frame, ret + 1, GSM_TCH_FRAME_AMR);
+#endif
+                       break;
                }
        }
 

diff --git a/gsm.h b/gsm.h
index b39b005..b0b9b89 100644 (file)
--- a/gsm.h
+++ b/gsm.h
@@ -51,6 +51,7 @@ class Pgsm : public Port
        void *p_g_fr_encoder, *p_g_fr_decoder;  /* gsm handle */
        void *p_g_hr_encoder, *p_g_hr_decoder;  /* gsm handle */
        void *p_g_amr_encoder, *p_g_amr_decoder;/* gsm handle */
+       int p_g_amr_cmr, p_g_amr_cmr_valid;
        signed short p_g_rxdata[160]; /* receive audio buffer */
        int p_g_rxpos; /* position in audio buffer 0..159 */
        int p_g_tch_connected; /* indicates if audio is connected */

diff --git a/gsm_audio.c b/gsm_audio.c
index eabf2f5..64756c7 100644 (file)
--- a/gsm_audio.c
+++ b/gsm_audio.c
@@ -132,7 +132,7 @@ int gsm_amr_encode(void *arg, signed short *samples, unsigned char *frame, int m
 
        frame[0] = 0xf0; /* no request */
 
-       return rv;
+       return rv + 1;
 }
 
 const unsigned short gsm690_12_2_bitorder[244] = {