Changeset 3837

Timestamp:

Oct 23, 2011 6:59:48 AM (13 years ago)

Author:

nanang

Message:

Re #1300: Implemented symmetric payload type in generating SDP answer in SDP negotiator.
This should work for all codecs, audio & video. Can be disabled at compile-time
using PJMEDIA_SDP_NEG_REWRITE_ANSWER_PT macro setting.

Location:

pjproject/trunk

Files:

• pjmedia/include/pjmedia/config.h (modified) (1 diff)
• pjmedia/include/pjmedia/stream.h (modified) (1 diff)
• pjmedia/src/pjmedia/sdp_neg.c (modified) (6 diffs)
• pjmedia/src/pjmedia/stream.c (modified) (6 diffs)
• pjmedia/src/pjmedia/vid_stream.c (modified) (2 diffs)
• pjsip/src/pjsua-lib/pjsua_dump.c (modified) (1 diff)

pjproject/trunk/pjmedia/include/pjmedia/config.h

@@ -621 +621 @@
 
 /**
+ * This specifies if the SDP negotiator should rewrite answer payload
+ * type numbers to use the same payload type numbers as the remote offer
+ * for all matched codecs.
+ *
+ * Default is 1 (yes)
+ */
+#ifndef PJMEDIA_SDP_NEG_ANSWER_SYMMETRIC_PT
+#   define PJMEDIA_SDP_NEG_ANSWER_SYMMETRIC_PT          1
+#endif
+
+
+/**
  * Support for sending and decoding RTCP port in SDP (RFC 3605).
  * Default is equal to PJMEDIA_ADVERTISE_RTCP setting.

pjproject/trunk/pjmedia/include/pjmedia/stream.h

@@ -111 +111 @@
     pjmedia_codec_param *param;     /**< Optional codec param.              */
     unsigned            tx_pt;      /**< Outgoing codec paylaod type.       */
+    unsigned            rx_pt;      /**< Incoming codec paylaod type.       */
     unsigned            tx_maxptime;/**< Outgoing codec max ptime.          */
     int                 tx_event_pt;/**< Outgoing pt for telephone-events.  */

pjproject/trunk/pjmedia/src/pjmedia/sdp_neg.c

@@ -1121 +1121 @@
 }
 
+
+/* Internal function to rewrite the format string in SDP attribute rtpmap
+ * and fmtp.
+ */
+PJ_INLINE(void) rewrite_pt(pj_pool_t *pool, pj_str_t *attr_val,
+                           const pj_str_t *old_pt, const pj_str_t *new_pt)
+{
+    int len_diff = new_pt->slen - old_pt->slen;
+
+    /* Note that attribute value should be null-terminated. */
+    if (len_diff > 0) {
+        pj_str_t new_val;
+        new_val.ptr = (char*)pj_pool_alloc(pool, attr_val->slen+len_diff+1);
+        new_val.slen = attr_val->slen + len_diff;
+        pj_memcpy(new_val.ptr + len_diff, attr_val->ptr, attr_val->slen + 1);
+        *attr_val = new_val;
+    } else if (len_diff < 0) {
+        pj_memmove(attr_val->ptr, attr_val->ptr - len_diff,
+                   attr_val->slen + len_diff + 1);
+    }
+    pj_memcpy(attr_val->ptr, new_pt->ptr, new_pt->slen);
+}
+
+
+/* Internal function to apply symmetric PT for the local answer. */
+static void apply_answer_symmetric_pt(pj_pool_t *pool,
+                                      pjmedia_sdp_media *answer,
+                                      unsigned pt_cnt,
+                                      const pj_str_t pt_offer[],
+                                      const pj_str_t pt_answer[])
+{
+    pjmedia_sdp_attr *a_tmp[PJMEDIA_MAX_SDP_ATTR];
+    unsigned i, a_tmp_cnt = 0;
+
+    /* Rewrite the payload types in the answer if different to
+     * the ones in the offer.
+     */
+    for (i = 0; i < pt_cnt; ++i) {
+        pjmedia_sdp_attr *a;
+
+        /* Skip if the PTs are the same already, e.g: static PT. */
+        if (pj_strcmp(&pt_answer[i], &pt_offer[i]) == 0)
+            continue;
+
+        /* Rewrite payload type in the answer to match to the offer */
+        pj_strdup(pool, &answer->desc.fmt[i], &pt_offer[i]);
+
+        /* Also update payload type in rtpmap */
+        a = pjmedia_sdp_media_find_attr2(answer, "rtpmap", &pt_answer[i]);
+        if (a) {
+            rewrite_pt(pool, &a->value, &pt_answer[i], &pt_offer[i]);
+            /* Temporarily remove the attribute in case the new payload
+             * type is being used by another format in the media.
+             */
+            pjmedia_sdp_media_remove_attr(answer, a);
+            a_tmp[a_tmp_cnt++] = a;
+        }
+
+        /* Also update payload type in fmtp */
+        a = pjmedia_sdp_media_find_attr2(answer, "fmtp", &pt_answer[i]);
+        if (a) {
+            rewrite_pt(pool, &a->value, &pt_answer[i], &pt_offer[i]);
+            /* Temporarily remove the attribute in case the new payload
+             * type is being used by another format in the media.
+             */
+            pjmedia_sdp_media_remove_attr(answer, a);
+            a_tmp[a_tmp_cnt++] = a;
+        }
+    }
+
+    /* Return back 'rtpmap' and 'fmtp' attributes */
+    for (i = 0; i < a_tmp_cnt; ++i)
+        pjmedia_sdp_media_add_attr(answer, a_tmp[i]);
+}
+
+
 /* Try to match offer with answer. */
 static pj_status_t match_offer(pj_pool_t *pool,
@@ -1138 +1214 @@
     unsigned pt_answer_count = 0;
     pj_str_t pt_answer[PJMEDIA_MAX_SDP_FMT];
+    pj_str_t pt_offer[PJMEDIA_MAX_SDP_FMT];
     pjmedia_sdp_media *answer;
     const pjmedia_sdp_media *master, *slave;
@@ -1202 +1279 @@
                     if (p == pt && pj_isdigit(*slave->desc.fmt[j].ptr)) {
                         found_matching_codec = 1;
+                        pt_offer[pt_answer_count] = slave->desc.fmt[j];
                         pt_answer[pt_answer_count++] = slave->desc.fmt[j];
                         break;
@@ -1301 +1379 @@
                             }
 
+                            pt_offer[pt_answer_count] = 
+                                                prefer_remote_codec_order?
+                                                offer->desc.fmt[i]:
+                                                offer->desc.fmt[j];
                             pt_answer[pt_answer_count++] = 
                                                 prefer_remote_codec_order? 
@@ -1326 +1408 @@
                     /* Match */
                     found_matching_other = 1;
+                    pt_offer[pt_answer_count] = prefer_remote_codec_order?
+                                                offer->desc.fmt[i]:
+                                                offer->desc.fmt[j];
                     pt_answer[pt_answer_count++] = prefer_remote_codec_order? 
                                                    preanswer->desc.fmt[j]:
@@ -1390 +1475 @@
     }
     answer->desc.fmt_count = pt_answer_count;
+
+#if PJMEDIA_SDP_NEG_ANSWER_SYMMETRIC_PT
+    apply_answer_symmetric_pt(pool, answer, pt_answer_count,
+                              pt_offer, pt_answer);
+#endif
 
     /* Update media direction. */

pjproject/trunk/pjmedia/src/pjmedia/stream.c

@@ -2221 +2221 @@
 
     status = create_channel( pool, stream, PJMEDIA_DIR_DECODING, 
-                             info->fmt.pt, info, &stream->dec);
+                             info->rx_pt, info, &stream->dec);
     if (status != PJ_SUCCESS)
         goto err_cleanup;
@@ -2835 +2835 @@
         return PJMEDIA_EINVALIDPT;
 
+    /* Get payload type for receiving direction */
+    si->rx_pt = pt;
+
     /* Get codec info.
      * For static payload types, get the info from codec manager.
@@ -2894 +2897 @@
 
     } else {
+        pjmedia_codec_id codec_id;
+        pj_str_t codec_id_st;
+        const pjmedia_codec_info *p_info;
 
         attr = pjmedia_sdp_media_find_attr(local_m, &ID_RTPMAP, 
@@ -2908 +2914 @@
         si->fmt.type = si->type;
         si->fmt.pt = pj_strtoul(&local_m->desc.fmt[fmti]);
-        pj_strdup(pool, &si->fmt.encoding_name, &rtpmap->enc_name);
+        si->fmt.encoding_name = rtpmap->enc_name;
         si->fmt.clock_rate = rtpmap->clock_rate;
 
@@ -2919 +2925 @@
             si->fmt.channel_cnt = 1;
         }
+
+        /* Normalize the codec info from codec manager. Note that the
+         * payload type will be resetted to its default (it might have
+         * been rewritten by the SDP negotiator to match to the remote
+         * offer), this is intentional as currently some components may
+         * prefer (or even require) the default PT in codec info.
+         */
+        pjmedia_codec_info_to_id(&si->fmt, codec_id, sizeof(codec_id));
+
+        i = 1;
+        codec_id_st = pj_str(codec_id);
+        status = pjmedia_codec_mgr_find_codecs_by_id(mgr, &codec_id_st,
+                                                     &i, &p_info, NULL);
+        if (status != PJ_SUCCESS)
+            return status;
+
+        pj_memcpy(&si->fmt, p_info, sizeof(pjmedia_codec_info));
 
         /* Determine payload type for outgoing channel, by finding
@@ -2966 +2989 @@
 
     /* Get local fmtp for our decoder. */
-    pjmedia_stream_info_parse_fmtp(pool, local_m, si->fmt.pt,
+    pjmedia_stream_info_parse_fmtp(pool, local_m, si->rx_pt,
                                    &si->param->setting.dec_fmtp);
 

pjproject/trunk/pjmedia/src/pjmedia/vid_stream.c

@@ -1783 +1783 @@
     pt = pj_strtoul(&local_m->desc.fmt[0]);
 
-    /* Get codec info. */
-    status = pjmedia_vid_codec_mgr_get_codec_info(mgr, pt, &p_info);
-    if (status != PJ_SUCCESS)
-        return status;
-
-    si->codec_info = *p_info;
-
     /* Get payload type for receiving direction */
     si->rx_pt = pt;
 
-    /* Get payload type for transmitting direction */
+    /* Get codec info and payload type for transmitting direction. */
     if (pt < 96) {
-        /* For static payload type, pt's are symetric */
+        /* For static payload types, get the codec info from codec manager. */
+        status = pjmedia_vid_codec_mgr_get_codec_info(mgr, pt, &p_info);
+        if (status != PJ_SUCCESS)
+            return status;
+
+        si->codec_info = *p_info;
+
+        /* Get payload type for transmitting direction.
+         * For static payload type, pt's are symetric.
+         */
         si->tx_pt = pt;
-
     } else {
+        const pjmedia_sdp_attr *attr;
+        pjmedia_sdp_rtpmap *rtpmap;
+        pjmedia_codec_id codec_id;
+        pj_str_t codec_id_st;
         unsigned i;
 
@@ -1819 +1824 @@
         if (si->tx_pt == 0xFFFF)
             return PJMEDIA_EMISSINGRTPMAP;
+
+        /* For dynamic payload types, get codec name from the rtpmap */
+        attr = pjmedia_sdp_media_find_attr(local_m, &ID_RTPMAP, 
+                                           &local_m->desc.fmt[0]);
+        if (attr == NULL)
+            return PJMEDIA_EMISSINGRTPMAP;
+
+        status = pjmedia_sdp_attr_to_rtpmap(pool, attr, &rtpmap);
+        if (status != PJ_SUCCESS)
+            return status;
+
+        /* Then get the codec info from the codec manager */
+        pj_ansi_snprintf(codec_id, sizeof(codec_id), "%.*s/", 
+                         rtpmap->enc_name.slen, rtpmap->enc_name.ptr);
+        codec_id_st = pj_str(codec_id);
+        i = 1;
+        status = pjmedia_vid_codec_mgr_find_codecs_by_id(mgr, &codec_id_st,
+                                                         &i, &p_info, NULL);
+        if (status != PJ_SUCCESS)
+            return status;
+
+        si->codec_info = *p_info;
     }
 

pjproject/trunk/pjsip/src/pjsua-lib/pjsua_dump.c

@@ -308 +308 @@
                              info.fmt.clock_rate / 1000);
             pj_ansi_snprintf(rx_info, sizeof(rx_info), "pt=%d,",
-                             info.fmt.pt);
+                             info.rx_pt);
             pj_ansi_snprintf(tx_info, sizeof(tx_info), "pt=%d, ptime=%d,",
                              info.tx_pt,