Changeset 2757

Timestamp:

Jun 9, 2009 1:05:18 PM (15 years ago)

Author:

nanang

Message:

Ticket #830: Fixed noise from EC by keeping the playing frames unmodified (pjmedia_delay_buf_put() may modify the input frames and there is a case that the modified frames are not aligned anymore).

File:

• pjproject/trunk/pjmedia/src/pjmedia/echo_common.c (modified) (5 diffs)

pjproject/trunk/pjmedia/src/pjmedia/echo_common.c

@@ -53 +53 @@
 
     pjmedia_delay_buf   *delay_buf;
+    pj_int16_t      *frm_buf;
 };
 
@@ -153 +154 @@
     ec->pool = pool;
     ec->obj_name = pool->obj_name;
+    ec->samples_per_frame = samples_per_frame;
+    ec->frm_buf = (pj_int16_t*)pj_pool_alloc(pool, samples_per_frame<<1);
     pj_list_init(&ec->lat_buf);
     pj_list_init(&ec->lat_free);
@@ -275 +278 @@
                                            pj_int16_t *play_frm )
 {
+    /* Playing frame should be stored, as it will be used by echo_capture() 
+     * as reference frame, delay buffer is used for storing the playing frames
+     * as in case there was clock drift between mic & speaker.
+     *
+     * Ticket #830:
+     * Note that pjmedia_delay_buf_put() may modify the input frame and those
+     * modified frames may not be smooth, i.e: if there were two or more
+     * consecutive pjmedia_delay_buf_get() before next pjmedia_delay_buf_put(),
+     * so we'll just feed the delay buffer with the copy of playing frame,
+     * instead of the original playing frame. However this will cause the EC 
+     * uses slight 'different' frames (for reference) than actually played 
+     * by the speaker.
+     */
+    pjmedia_copy_samples(echo->frm_buf, play_frm, 
+                         echo->samples_per_frame);
+    pjmedia_delay_buf_put(echo->delay_buf, echo->frm_buf);
+
     if (!echo->lat_ready) {
         /* We've not built enough latency in the buffer, so put this frame
@@ -284 +304 @@
             echo->lat_ready = PJ_TRUE;
             PJ_LOG(5,(echo->obj_name, "Latency bufferring complete"));
-            pjmedia_delay_buf_put(echo->delay_buf, play_frm);
             return PJ_SUCCESS;
         }
@@ -291 +310 @@
         pj_list_erase(frm);
 
-        pjmedia_copy_samples(frm->buf, play_frm, echo->samples_per_frame);
+        /* Move one frame from delay buffer to the latency buffer. */
+        pjmedia_delay_buf_get(echo->delay_buf, echo->frm_buf);
+        pjmedia_copy_samples(frm->buf, echo->frm_buf, echo->samples_per_frame);
         pj_list_push_back(&echo->lat_buf, frm);
-
-    } else {
-        /* Latency buffer is ready (full), so we put this frame in the
-         * delay buffer.
-         */
-        pjmedia_delay_buf_put(echo->delay_buf, play_frm);
     }