Changeset 415

Timestamp:

Apr 28, 2006 1:00:26 AM (19 years ago)

Author:

bennylp

Message:

Implement simple frame replay based packet lost concealment

File:

• pjproject/trunk/pjmedia/src/pjmedia/sound_port.c (modified) (14 diffs)

pjproject/trunk/pjmedia/src/pjmedia/sound_port.c

@@ -20 +20 @@
 #include <pjmedia/errno.h>
 #include <pj/assert.h>
+#include <pj/log.h>
+#include <pj/rand.h>
 #include <pj/string.h>      /* pj_memset() */
+
+
+//#define SIMULATE_LOST_PCT   10
+
+
+#define THIS_FILE           "sound_port.c"
+
+enum
+{
+    PJMEDIA_PLC_ENABLED     = 1,
+};
+
+#define DEFAULT_OPTIONS PJMEDIA_PLC_ENABLED
+
+
 
 struct pjmedia_snd_port
@@ -29 +46 @@
     pjmedia_dir          dir;
     pjmedia_port        *port;
+    unsigned             options;
+
+    void                *last_frame;
+    unsigned             last_frame_size;
+    unsigned             last_replay_count;
 
     unsigned             clock_rate;
@@ -74 +96 @@
     pj_assert(frame.size == size);
 
+#ifdef SIMULATE_LOST_PCT
+    /* Simulate packet lost */
+    if (pj_rand() % 100 < SIMULATE_LOST_PCT) {
+        PJ_LOG(4,(THIS_FILE, "Frame dropped"));
+        goto no_frame;
+    }
+#endif
+
+    /* Keep frame if PLC is enabled. */
+    if (snd_port->options & PJMEDIA_PLC_ENABLED) {
+        /* Must have the same length as last_frame_size */
+        pj_assert(frame.size == snd_port->last_frame_size);
+
+        /* Copy frame to last_frame */
+        pj_memcpy(snd_port->last_frame, output, snd_port->last_frame_size);
+
+        snd_port->last_replay_count = 0;
+    }
+
     return PJ_SUCCESS;
 
 no_frame:
-    pj_memset(output, 0, size);
+
+    /* Replay last frame if PLC is enabled */
+    if ((snd_port->options & PJMEDIA_PLC_ENABLED) &&
+        snd_port->last_replay_count < 8) 
+    {
+
+        /* Must have the same length as last_frame_size */
+        pj_assert(size == snd_port->last_frame_size);
+
+        /* Replay last frame */
+        pj_memcpy(output, snd_port->last_frame, snd_port->last_frame_size);
+
+        /* Reduce replay frame signal level to half */
+        if (snd_port->bits_per_sample == 16) {
+            unsigned i, count;
+            pj_int16_t *samp;
+
+            count = snd_port->last_frame_size / 2;
+            samp = (pj_int16_t *) snd_port->last_frame;
+
+            for (i=0; i<count; ++i)
+                samp[i] = (pj_int16_t) (samp[i] >> 2);
+
+        }
+
+#ifdef SIMULATE_LOST_PCT
+        PJ_LOG(4,(THIS_FILE, "Frame replayed"));
+#endif
+
+        ++snd_port->last_replay_count;
+
+    } else {
+
+        /* Just zero the frame */
+        pj_memset(output, 0, size);
+
+    }
+
+
     return PJ_SUCCESS;
 }
@@ -119 +198 @@
  * This may be called even when the sound stream has already been started.
  */
-static pj_status_t start_sound_device( pjmedia_snd_port *snd_port )
+static pj_status_t start_sound_device( pj_pool_t *pool,
+                                       pjmedia_snd_port *snd_port )
 {
     pj_status_t status;
@@ -167 +247 @@
         return status;
 
+
+    /* If we have player components, allocate buffer to save the last
+     * frame played to the speaker. The last frame is used for packet
+     * lost concealment (PLC) algorithm.
+     */
+    if ((snd_port->dir & PJMEDIA_DIR_PLAYBACK) &&
+        (snd_port->options & PJMEDIA_PLC_ENABLED)) 
+    {
+
+        snd_port->last_frame_size = snd_port->samples_per_frame *
+                                    snd_port->channel_count *
+                                    snd_port->bits_per_sample / 8;
+        snd_port->last_frame = pj_pool_zalloc(pool, 
+                                              snd_port->last_frame_size);
+    }
+
     /* Start sound stream. */
     status = pjmedia_snd_stream_start(snd_port->snd_stream);
@@ -212 +308 @@
 
     PJ_ASSERT_RETURN(pool && p_port, PJ_EINVAL);
-    PJ_ASSERT_RETURN(options == 0, PJ_EINVAL);
 
     snd_port = pj_pool_zalloc(pool, sizeof(pjmedia_snd_port));
@@ -220 +315 @@
     snd_port->play_id = play_id;
     snd_port->dir = PJMEDIA_DIR_CAPTURE_PLAYBACK;
+    snd_port->options = options | DEFAULT_OPTIONS;
     snd_port->clock_rate = clock_rate;
     snd_port->channel_count = channel_count;
@@ -227 +323 @@
     *p_port = snd_port;
 
+
     /* Start sound device immediately.
      * If there's no port connected, the sound callback will return
      * empty signal.
      */
-    return start_sound_device( snd_port );
+    return start_sound_device( pool, snd_port );
 
 }
@@ -250 +347 @@
 
     PJ_ASSERT_RETURN(pool && p_port, PJ_EINVAL);
-    PJ_ASSERT_RETURN(options == 0, PJ_EINVAL);
 
     snd_port = pj_pool_zalloc(pool, sizeof(pjmedia_snd_port));
@@ -257 +353 @@
     snd_port->rec_id = dev_id;
     snd_port->dir = PJMEDIA_DIR_CAPTURE;
+    snd_port->options = options | DEFAULT_OPTIONS;
     snd_port->clock_rate = clock_rate;
     snd_port->channel_count = channel_count;
@@ -268 +365 @@
      * empty signal.
      */
-    return start_sound_device( snd_port );
+    return start_sound_device( pool, snd_port );
 }
 
@@ -287 +384 @@
 
     PJ_ASSERT_RETURN(pool && p_port, PJ_EINVAL);
-    PJ_ASSERT_RETURN(options == 0, PJ_EINVAL);
 
     snd_port = pj_pool_zalloc(pool, sizeof(pjmedia_snd_port));
@@ -294 +390 @@
     snd_port->play_id = dev_id;
     snd_port->dir = PJMEDIA_DIR_PLAYBACK;
+    snd_port->options = options | DEFAULT_OPTIONS;
     snd_port->clock_rate = clock_rate;
     snd_port->channel_count = channel_count;
@@ -305 +402 @@
      * empty signal.
      */
-    return start_sound_device( snd_port );
+    return start_sound_device( pool, snd_port );
 }