Changeset 4554

Timestamp:

Jul 9, 2013 7:17:39 AM (11 years ago)

Author:

ming

Message:

Closed #1687: Allow media type change during SDP negotiation

Location:

pjproject/trunk/pjmedia

Files:

• include/pjmedia/sdp_neg.h (modified) (4 diffs)
• src/pjmedia/sdp_neg.c (modified) (2 diffs)

pjproject/trunk/pjmedia/include/pjmedia/sdp_neg.h

@@ -314 +314 @@
 
 /**
+ * Flags to be given to pjmedia_sdp_neg_modify_local_offer2().
+ */
+typedef enum pjmedia_mod_offer_flag
+{
+   /**
+    * Allow media type in the SDP to be changed.
+    * When generating a new offer, in the case that a media line doesn't match
+    * the active SDP, the new media line will be considered to replace the
+    * existing media at the same position.
+    */
+   PJMEDIA_SDP_NEG_ALLOW_MEDIA_CHANGE = 1
+
+} pjmedia_mod_offer_flag;
+
+
+/**
  * Get the state string description of the specified state.
  *
@@ -494 +510 @@
 pjmedia_sdp_neg_get_neg_local( pjmedia_sdp_neg *neg,
                                const pjmedia_sdp_session **local);
+
+/**
+ * Modify local session with a new SDP and treat this as a new offer. 
+ * This function can only be called in state PJMEDIA_SDP_NEG_STATE_DONE.
+ * After calling this function, application can send the SDP as offer 
+ * to remote party, using signaling protocol such as SIP.
+ * The negotiator state will move to PJMEDIA_SDP_NEG_STATE_LOCAL_OFFER,
+ * where it waits for SDP answer from remote. See also
+ * #pjmedia_sdp_neg_modify_local_offer2()
+ *
+ * @param pool          Pool to allocate memory. The pool's lifetime needs
+ *                      to be valid for the duration of the negotiator.
+ * @param neg           The SDP negotiator instance.
+ * @param local         The new local SDP.
+ *
+ * @return              PJ_SUCCESS on success, or the appropriate
+ *                      error code.
+ */
+PJ_DECL(pj_status_t) 
+pjmedia_sdp_neg_modify_local_offer( pj_pool_t *pool,
+                                    pjmedia_sdp_neg *neg,
+                                    const pjmedia_sdp_session *local);
 
 /**
@@ -506 +544 @@
  *                      to be valid for the duration of the negotiator.
  * @param neg           The SDP negotiator instance.
+ * @param flags         Bitmask from pjmedia_mod_offer_flag.
  * @param local         The new local SDP.
  *
@@ -512 +551 @@
  */
 PJ_DECL(pj_status_t) 
-pjmedia_sdp_neg_modify_local_offer( pj_pool_t *pool,
-                                    pjmedia_sdp_neg *neg,
-                                    const pjmedia_sdp_session *local);
+pjmedia_sdp_neg_modify_local_offer2( pj_pool_t *pool,
+                                     pjmedia_sdp_neg *neg,
+                                     unsigned flags,
+                                     const pjmedia_sdp_session *local);
 
 /**

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

@@ -277 +277 @@
                                     const pjmedia_sdp_session *local)
 {
+    return pjmedia_sdp_neg_modify_local_offer2(pool, neg, 0, local);
+}
+
+PJ_DEF(pj_status_t) pjmedia_sdp_neg_modify_local_offer2(
+                                    pj_pool_t *pool,
+                                    pjmedia_sdp_neg *neg,
+                                    unsigned flags,
+                                    const pjmedia_sdp_session *local)
+{
     pjmedia_sdp_session *new_offer;
     pjmedia_sdp_session *old_offer;
@@ -315 +324 @@
     pj_strdup(pool, &new_offer->origin.addr, &old_offer->origin.addr);
 
-    /* Generating the new offer, in the case media lines doesn't match the
-     * active SDP (e.g. current/active SDP's have m=audio and m=video lines, 
-     * and the new offer only has m=audio line), the negotiator will fix 
-     * the new offer by reordering and adding the missing media line with 
-     * port number set to zero.
-     */
-    for (oi = 0; oi < old_offer->media_count; ++oi) {
-        pjmedia_sdp_media *om;
-        pjmedia_sdp_media *nm;
-        unsigned ni; /* new offer media index */
-        pj_bool_t found = PJ_FALSE;
-
-        om = old_offer->media[oi];
-        for (ni = oi; ni < new_offer->media_count; ++ni) {
-            nm = new_offer->media[ni];
-            if (pj_strcmp(&nm->desc.media, &om->desc.media) == 0) {
-                if (ni != oi) {
-                    /* The same media found but the position unmatched to the 
-                     * old offer, so let's put this media in the right place, 
-                     * and keep the order of the rest.
-                     */
-                    pj_array_insert(new_offer->media,            /* array    */
-                                    sizeof(new_offer->media[0]), /* elmt size*/
-                                    ni,                          /* count    */
-                                    oi,                          /* pos      */
-                                    &nm);                        /* new elmt */
-                }
-                found = PJ_TRUE;
-                break;
+    if ((flags & PJMEDIA_SDP_NEG_ALLOW_MEDIA_CHANGE) == 0) {
+       /* Generating the new offer, in the case media lines doesn't match the
+        * active SDP (e.g. current/active SDP's have m=audio and m=video lines,
+        * and the new offer only has m=audio line), the negotiator will fix 
+        * the new offer by reordering and adding the missing media line with 
+        * port number set to zero.
+        */
+        for (oi = 0; oi < old_offer->media_count; ++oi) {
+            pjmedia_sdp_media *om;
+            pjmedia_sdp_media *nm;
+            unsigned ni; /* new offer media index */
+            pj_bool_t found = PJ_FALSE;
+
+            om = old_offer->media[oi];
+            for (ni = oi; ni < new_offer->media_count; ++ni) {
+                nm = new_offer->media[ni];
+                if (pj_strcmp(&nm->desc.media, &om->desc.media) == 0) {
+                    if (ni != oi) {
+                        /* The same media found but the position unmatched to
+                         * the old offer, so let's put this media in the right
+                         * place, and keep the order of the rest.
+                         */
+                        pj_array_insert(
+                            new_offer->media,            /* array    */
+                            sizeof(new_offer->media[0]), /* elmt size*/
+                            ni,                          /* count    */
+                            oi,                          /* pos      */
+                            &nm);                        /* new elmt */
+                    }
+                    found = PJ_TRUE;
+                    break;
+                }
             }
-        }
-        if (!found) {
-            pjmedia_sdp_media *m;
-
-            m = sdp_media_clone_deactivate(pool, om, om, local);
+            if (!found) {
+                pjmedia_sdp_media *m;
+
+                m = sdp_media_clone_deactivate(pool, om, om, local);
+
+                pj_array_insert(new_offer->media, sizeof(new_offer->media[0]),
+                                new_offer->media_count++, oi, &m);
+            }
+        }
+    } else {
+        /* If media type change is allowed, the negotiator only needs to fix 
+         * the new offer by adding the missing media line(s) with port number
+         * set to zero.
+         */
+        for (oi = new_offer->media_count; oi < old_offer->media_count; ++oi) {
+            pjmedia_sdp_media *m;
+
+            m = sdp_media_clone_deactivate(pool, old_offer->media[oi],
+                                           old_offer->media[oi], local);
 
             pj_array_insert(new_offer->media, sizeof(new_offer->media[0]),
-                            new_offer->media_count++, oi, &m);
-        }
+                            new_offer->media_count++, oi, &m);
+
+        }
     }